Medusa - User contributions [en]

Pinouts

2024-04-30T17:00:17Z

Acid: /* Digital Input (DB9 - Rev B only) */

== SCART ==

{| class="wikitable"
! style="color:black" | Pin number !! style="color:black" | EURO version !! style="color:black" | JP21 version
|-
| 1 || - || Audio Left
|-
| 2 || Audio Right || -
|-
| 3 || - || GND
|-
| 4 || GND || GND
|-
| 5 || GND || Audio Right
|-
| 6 || Audio Left || -
|-
| 7 || Video Blue || GND
|-
| 8 || - || GND
|-
| 9 || GND || Composite Video / Video Luma
|-
| 10 || - || -
|-
| 11 || Video Green || -
|-
| 12 || - || -
|-
| 13 || GND || GND
|-
| 14 || - || GND
|-
| 15 || Video Red / Chroma || Video Red / Chroma
|-
| 16 || Blank (RGB detect) || Blank (RGB detect)
|-
| 17 || GND || GND
|-
| 18 || GND || GND
|-
| 19 || - || Video Green
|-
| 20 || Composite Video / Luma || Video Blue
|-
| 21 || GND || GND
|}

* '-' means 'not connected'
* Blank - when average voltage on this pin is higher than 0.3V Medusa switches to RGB mode

== Digital Input (DB9 - Rev B only) ==

{| class="wikitable"
! style="color:black" | Pin number
!! style="color:black" | MDA/Hercules mode
!! style="color:black" | EGA mode
!! style="color:black" | RGBI/CGA mode
!! style="color:black" | digital RGB mode (Sinclair QL)
!! style="color:black" | Apple IIC mode
|-
| 1 || GND || GND || GND || Pin 2 / GND || Pin 13 / GND
|-
| 2 || - || Red 0 || - || - || Pin 2 / (14MHz - not used)
|-
| 3 || - || Red 1 || Red || Pin 7 / Red || Pin 6 / LDPS
|-
| 4 || - || Green 1 || Green || Pin 6 / Green || Pin 11 / SEROUT
|-
| 5 || - || Blue 1 || Blue || Pin 8 / Blue || Pin 10 / GR
|-
| 6 || Luma 1 || Green 0 || Intensity || - || Pin 14 / (VIDD7 - not used)
|-
| 7 || Luma 0 || Blue 0 || - || - || Pin 4 / (SEGB - not used)
|-
| 8 || HSYNC || HSYNC || HSYNC || Pin 4 / CSYNC || Pin 3 / CSYNC
|-
| 9 || VSYNC || VSYNC || VSYNC || - || -
|}

* '-' means 'signal ignored in this mode'
* MDA/CGA/EGA and Commodore 128 - signals are in the same order as on computer output, so standard DB9 1:1 cable is enough to connect this machines to Medusa
* digital RGB mode - used mainly with Sinclair QL - you will need DIN8 to DB9 cable (pin numbers for DIN8 are given in the table)
* Apple IIC - to connect Apple IIC you need cable from DB15 to DB9 (pin numbers on DB15 are given in the table) - when you prepare cable for Apple IIC be aware that there is 12V on pin number 8 - DO NOT CONNECT THIS PIN !!! - it may destroy Medusa.

== Analog Input (DB15 - VGA) ==

{| class="wikitable"
! style="color:black" | Pin number !! style="color:black" | Function
|-
| 1 || Red
|-
| 2 || Green
|-
| 3 || Blue
|-
| 4 || -
|-
| 5 || GND
|-
| 6 || GND
|-
| 7 || GND
|-
| 8 || GND
|-
| 9 || -
|-
| 10 || GND
|-
| 11 || -
|-
| 12 || -
|-
| 13 || HSYNC/CSYNC
|-
| 14 || VSYNC
|-
| 15 || -
|}

* '-' means 'not connected'

Pinouts

2024-04-30T16:58:43Z

Acid: /* Digital Input (DB9 - Rev B only) */

== SCART ==

{| class="wikitable"
! style="color:black" | Pin number !! style="color:black" | EURO version !! style="color:black" | JP21 version
|-
| 1 || - || Audio Left
|-
| 2 || Audio Right || -
|-
| 3 || - || GND
|-
| 4 || GND || GND
|-
| 5 || GND || Audio Right
|-
| 6 || Audio Left || -
|-
| 7 || Video Blue || GND
|-
| 8 || - || GND
|-
| 9 || GND || Composite Video / Video Luma
|-
| 10 || - || -
|-
| 11 || Video Green || -
|-
| 12 || - || -
|-
| 13 || GND || GND
|-
| 14 || - || GND
|-
| 15 || Video Red / Chroma || Video Red / Chroma
|-
| 16 || Blank (RGB detect) || Blank (RGB detect)
|-
| 17 || GND || GND
|-
| 18 || GND || GND
|-
| 19 || - || Video Green
|-
| 20 || Composite Video / Luma || Video Blue
|-
| 21 || GND || GND
|}

* '-' means 'not connected'
* Blank - when average voltage on this pin is higher than 0.3V Medusa switches to RGB mode

== Digital Input (DB9 - Rev B only) ==

{| class="wikitable"
! style="color:black" | Pin number
!! style="color:black" | MDA/Hercules mode
!! style="color:black" | EGA mode
!! style="color:black" | RGBI/CGA mode
!! style="color:black" | digital RGB mode (Sinclair QL)
!! style="color:black" | Apple IIC mode
|-
| 1 || GND || GND || GND || Pin 2 / GND || Pin 13 / GND
|-
| 2 || - || Red 0 || - || - || Pin 2 / (14MHz - not used)
|-
| 3 || - || Red 1 || Red || Pin 7 / Red || Pin 6 / LDPS
|-
| 4 || - || Green 1 || Green || Pin 6 / Green || Pin 11 / SEROUT
|-
| 5 || - || Blue 1 || Blue || Pin 8 / Blue || Pin 10 / GR
|-
| 6 || Luma 1 || Green 0 || Intensity || - || Pin 14 / (VIDD7 - not used)
|-
| 7 || Luma 0 || Blue 0 || - || - || Pin 4 / (SEGB - not used)
|-
| 8 || HSYNC || HSYNC || HSYNC || Pin 4 / CSYNC || Pin 3 / CSYNC
|-
| 9 || VSYNC || VSYNC || VSYNC || - || -
|}

* '-' means 'signal ignored in this mode'
* MDA/CGA/EGA and Commodore 128 - signals are in the same order as on computer output, so standard DB9 1:1 cable is enough to connect this machines to Medusa
* Apple IIC - to connect Apple IIC you need cable from DB15 to DB9 (pin numbers on DB15 are given in the table) - when you prepare cable for Apple IIC be aware that there is 12V on pin number 8 - DO NOT CONNECT THIS PIN !!! - it may destroy Medusa.

== Analog Input (DB15 - VGA) ==

{| class="wikitable"
! style="color:black" | Pin number !! style="color:black" | Function
|-
| 1 || Red
|-
| 2 || Green
|-
| 3 || Blue
|-
| 4 || -
|-
| 5 || GND
|-
| 6 || GND
|-
| 7 || GND
|-
| 8 || GND
|-
| 9 || -
|-
| 10 || GND
|-
| 11 || -
|-
| 12 || -
|-
| 13 || HSYNC/CSYNC
|-
| 14 || VSYNC
|-
| 15 || -
|}

* '-' means 'not connected'

Pinouts

2024-04-30T15:06:50Z

Acid: /* SCART */

== SCART ==

{| class="wikitable"
! style="color:black" | Pin number !! style="color:black" | EURO version !! style="color:black" | JP21 version
|-
| 1 || - || Audio Left
|-
| 2 || Audio Right || -
|-
| 3 || - || GND
|-
| 4 || GND || GND
|-
| 5 || GND || Audio Right
|-
| 6 || Audio Left || -
|-
| 7 || Video Blue || GND
|-
| 8 || - || GND
|-
| 9 || GND || Composite Video / Video Luma
|-
| 10 || - || -
|-
| 11 || Video Green || -
|-
| 12 || - || -
|-
| 13 || GND || GND
|-
| 14 || - || GND
|-
| 15 || Video Red / Chroma || Video Red / Chroma
|-
| 16 || Blank (RGB detect) || Blank (RGB detect)
|-
| 17 || GND || GND
|-
| 18 || GND || GND
|-
| 19 || - || Video Green
|-
| 20 || Composite Video / Luma || Video Blue
|-
| 21 || GND || GND
|}

* '-' means 'not connected'
* Blank - when average voltage on this pin is higher than 0.3V Medusa switches to RGB mode

== Digital Input (DB9 - Rev B only) ==

{| class="wikitable"
! style="color:black" | Pin number !! style="color:black" | MDA/Hercules mode !! style="color:black" | EGA mode !! style="color:black" | RGBI/CGA mode !! style="color:black" | Apple IIC mode
|-
| 1 || GND || GND || GND || Pin 13 / GND
|-
| 2 || - || Red 0 || - || Pin 2 / (14MHz - not used)
|-
| 3 || - || Red 1 || Red || Pin 6 / LDPS
|-
| 4 || - || Green 1 || Green || Pin 11 / SEROUT
|-
| 5 || - || Blue 1 || Blue || Pin 10 / GR
|-
| 6 || Luma 1 || Green 0 || Intensity || Pin 14 / (VIDD7 - not used)
|-
| 7 || Luma 0 || Blue 0 || - || Pin 4 / (SEGB - not used)
|-
| 8 || HSYNC || HSYNC || HSYNC || Pin 3 / CSYNC
|-
| 9 || VSYNC || VSYNC || VSYNC || -
|}

* '-' means 'signal ignored in this mode'
* MDA/CGA/EGA and Commodore 128 - signals are in the same order as on computer output, so standard DB9 1:1 cable is enough to connect this machines to Medusa
* Apple IIC - to connect Apple IIC you need cable from DB15 to DB9 (pin numbers on DB15 are given in the table) - when you prepare cable for Apple IIC be aware that there is 12V on pin number 8 - DO NOT CONNECT THIS PIN !!! - it may destroy Medusa.

== Analog Input (DB15 - VGA) ==

{| class="wikitable"
! style="color:black" | Pin number !! style="color:black" | Function
|-
| 1 || Red
|-
| 2 || Green
|-
| 3 || Blue
|-
| 4 || -
|-
| 5 || GND
|-
| 6 || GND
|-
| 7 || GND
|-
| 8 || GND
|-
| 9 || -
|-
| 10 || GND
|-
| 11 || -
|-
| 12 || -
|-
| 13 || HSYNC/CSYNC
|-
| 14 || VSYNC
|-
| 15 || -
|}

* '-' means 'not connected'

Pinouts

2024-04-30T15:06:39Z

Acid: /* Digital Input (DB9 - Rev B only) */

== SCART ==

{| class="wikitable"
! style="color:black" | Pin number !! style="color:black" | EURO version !! style="color:black" | JP21 version
|-
| 1 || - || Audio Left
|-
| 2 || Audio Right || -
|-
| 3 || - || GND
|-
| 4 || GND || GND
|-
| 5 || GND || Audio Right
|-
| 6 || Audio Left || -
|-
| 7 || Video Blue || GND
|-
| 8 || - || GND
|-
| 9 || GND || Composite Video / Video Luma
|-
| 10 || - || -
|-
| 11 || Video Green || -
|-
| 12 || - || -
|-
| 13 || GND || GND
|-
| 14 || - || GND
|-
| 15 || Video Red / Chroma || Video Red / Chroma
|-
| 16 || Blank (RGB detect) || Blank (RGB detect)
|-
| 17 || GND || GND
|-
| 18 || GND || GND
|-
| 19 || - || Video Green
|-
| 20 || Composite Video / Luma || Video Blue
|-
| 21 || GND || GND
|}

* '-' - means 'not connected'
* Blank - when average voltage on this pin is higher than 0.3V Medusa switches to RGB mode

== Digital Input (DB9 - Rev B only) ==

{| class="wikitable"
! style="color:black" | Pin number !! style="color:black" | MDA/Hercules mode !! style="color:black" | EGA mode !! style="color:black" | RGBI/CGA mode !! style="color:black" | Apple IIC mode
|-
| 1 || GND || GND || GND || Pin 13 / GND
|-
| 2 || - || Red 0 || - || Pin 2 / (14MHz - not used)
|-
| 3 || - || Red 1 || Red || Pin 6 / LDPS
|-
| 4 || - || Green 1 || Green || Pin 11 / SEROUT
|-
| 5 || - || Blue 1 || Blue || Pin 10 / GR
|-
| 6 || Luma 1 || Green 0 || Intensity || Pin 14 / (VIDD7 - not used)
|-
| 7 || Luma 0 || Blue 0 || - || Pin 4 / (SEGB - not used)
|-
| 8 || HSYNC || HSYNC || HSYNC || Pin 3 / CSYNC
|-
| 9 || VSYNC || VSYNC || VSYNC || -
|}

* '-' means 'signal ignored in this mode'
* MDA/CGA/EGA and Commodore 128 - signals are in the same order as on computer output, so standard DB9 1:1 cable is enough to connect this machines to Medusa
* Apple IIC - to connect Apple IIC you need cable from DB15 to DB9 (pin numbers on DB15 are given in the table) - when you prepare cable for Apple IIC be aware that there is 12V on pin number 8 - DO NOT CONNECT THIS PIN !!! - it may destroy Medusa.

== Analog Input (DB15 - VGA) ==

{| class="wikitable"
! style="color:black" | Pin number !! style="color:black" | Function
|-
| 1 || Red
|-
| 2 || Green
|-
| 3 || Blue
|-
| 4 || -
|-
| 5 || GND
|-
| 6 || GND
|-
| 7 || GND
|-
| 8 || GND
|-
| 9 || -
|-
| 10 || GND
|-
| 11 || -
|-
| 12 || -
|-
| 13 || HSYNC/CSYNC
|-
| 14 || VSYNC
|-
| 15 || -
|}

* '-' means 'not connected'

Pinouts

2024-04-30T15:06:24Z

Acid: /* Analog Input (DB15 - VGA) */

== SCART ==

{| class="wikitable"
! style="color:black" | Pin number !! style="color:black" | EURO version !! style="color:black" | JP21 version
|-
| 1 || - || Audio Left
|-
| 2 || Audio Right || -
|-
| 3 || - || GND
|-
| 4 || GND || GND
|-
| 5 || GND || Audio Right
|-
| 6 || Audio Left || -
|-
| 7 || Video Blue || GND
|-
| 8 || - || GND
|-
| 9 || GND || Composite Video / Video Luma
|-
| 10 || - || -
|-
| 11 || Video Green || -
|-
| 12 || - || -
|-
| 13 || GND || GND
|-
| 14 || - || GND
|-
| 15 || Video Red / Chroma || Video Red / Chroma
|-
| 16 || Blank (RGB detect) || Blank (RGB detect)
|-
| 17 || GND || GND
|-
| 18 || GND || GND
|-
| 19 || - || Video Green
|-
| 20 || Composite Video / Luma || Video Blue
|-
| 21 || GND || GND
|}

* '-' - means 'not connected'
* Blank - when average voltage on this pin is higher than 0.3V Medusa switches to RGB mode

== Digital Input (DB9 - Rev B only) ==

{| class="wikitable"
! style="color:black" | Pin number !! style="color:black" | MDA/Hercules mode !! style="color:black" | EGA mode !! style="color:black" | RGBI/CGA mode !! style="color:black" | Apple IIC mode
|-
| 1 || GND || GND || GND || Pin 13 / GND
|-
| 2 || - || Red 0 || - || Pin 2 / (14MHz - not used)
|-
| 3 || - || Red 1 || Red || Pin 6 / LDPS
|-
| 4 || - || Green 1 || Green || Pin 11 / SEROUT
|-
| 5 || - || Blue 1 || Blue || Pin 10 / GR
|-
| 6 || Luma 1 || Green 0 || Intensity || Pin 14 / (VIDD7 - not used)
|-
| 7 || Luma 0 || Blue 0 || - || Pin 4 / (SEGB - not used)
|-
| 8 || HSYNC || HSYNC || HSYNC || Pin 3 / CSYNC
|-
| 9 || VSYNC || VSYNC || VSYNC || -
|}

* '-' - means 'signal ignored in this mode'
* MDA/CGA/EGA and Commodore 128 - signals are in the same order as on computer output, so standard DB9 1:1 cable is enough to connect this machines to Medusa
* Apple IIC - to connect Apple IIC you need cable from DB15 to DB9 (pin numbers on DB15 are given in the table) - when you prepare cable for Apple IIC be aware that there is 12V on pin number 8 - DO NOT CONNECT THIS PIN !!! - it may destroy Medusa.

== Analog Input (DB15 - VGA) ==

{| class="wikitable"
! style="color:black" | Pin number !! style="color:black" | Function
|-
| 1 || Red
|-
| 2 || Green
|-
| 3 || Blue
|-
| 4 || -
|-
| 5 || GND
|-
| 6 || GND
|-
| 7 || GND
|-
| 8 || GND
|-
| 9 || -
|-
| 10 || GND
|-
| 11 || -
|-
| 12 || -
|-
| 13 || HSYNC/CSYNC
|-
| 14 || VSYNC
|-
| 15 || -
|}

* '-' means 'not connected'

Pinouts

2024-04-30T15:05:38Z

Acid: /* Digital Input (DB9 - Rev B only) */

== SCART ==

{| class="wikitable"
! style="color:black" | Pin number !! style="color:black" | EURO version !! style="color:black" | JP21 version
|-
| 1 || - || Audio Left
|-
| 2 || Audio Right || -
|-
| 3 || - || GND
|-
| 4 || GND || GND
|-
| 5 || GND || Audio Right
|-
| 6 || Audio Left || -
|-
| 7 || Video Blue || GND
|-
| 8 || - || GND
|-
| 9 || GND || Composite Video / Video Luma
|-
| 10 || - || -
|-
| 11 || Video Green || -
|-
| 12 || - || -
|-
| 13 || GND || GND
|-
| 14 || - || GND
|-
| 15 || Video Red / Chroma || Video Red / Chroma
|-
| 16 || Blank (RGB detect) || Blank (RGB detect)
|-
| 17 || GND || GND
|-
| 18 || GND || GND
|-
| 19 || - || Video Green
|-
| 20 || Composite Video / Luma || Video Blue
|-
| 21 || GND || GND
|}

* '-' - means 'not connected'
* Blank - when average voltage on this pin is higher than 0.3V Medusa switches to RGB mode

== Digital Input (DB9 - Rev B only) ==

{| class="wikitable"
! style="color:black" | Pin number !! style="color:black" | MDA/Hercules mode !! style="color:black" | EGA mode !! style="color:black" | RGBI/CGA mode !! style="color:black" | Apple IIC mode
|-
| 1 || GND || GND || GND || Pin 13 / GND
|-
| 2 || - || Red 0 || - || Pin 2 / (14MHz - not used)
|-
| 3 || - || Red 1 || Red || Pin 6 / LDPS
|-
| 4 || - || Green 1 || Green || Pin 11 / SEROUT
|-
| 5 || - || Blue 1 || Blue || Pin 10 / GR
|-
| 6 || Luma 1 || Green 0 || Intensity || Pin 14 / (VIDD7 - not used)
|-
| 7 || Luma 0 || Blue 0 || - || Pin 4 / (SEGB - not used)
|-
| 8 || HSYNC || HSYNC || HSYNC || Pin 3 / CSYNC
|-
| 9 || VSYNC || VSYNC || VSYNC || -
|}

* '-' - means 'signal ignored in this mode'
* MDA/CGA/EGA and Commodore 128 - signals are in the same order as on computer output, so standard DB9 1:1 cable is enough to connect this machines to Medusa
* Apple IIC - to connect Apple IIC you need cable from DB15 to DB9 (pin numbers on DB15 are given in the table) - when you prepare cable for Apple IIC be aware that there is 12V on pin number 8 - DO NOT CONNECT THIS PIN !!! - it may destroy Medusa.

== Analog Input (DB15 - VGA) ==

{| class="wikitable"
! style="color:black" | Pin number !! style="color:black" | Function
|-
| 1 || Red
|-
| 2 || Green
|-
| 3 || Blue
|-
| 4 || -
|-
| 5 || GND
|-
| 6 || GND
|-
| 7 || GND
|-
| 8 || GND
|-
| 9 || -
|-
| 10 || GND
|-
| 11 || -
|-
| 12 || -
|-
| 13 || HSYNC/CSYNC
|-
| 14 || VSYNC
|-
| 15 || -
|}

Pinouts

2024-04-30T14:55:44Z

Acid: /* SCART */

Pinouts

2024-04-30T14:49:10Z

Acid: /* Digital Input (DB9 - Rev B only) */

Pinouts

2024-04-30T14:47:51Z

Acid: Created page with "== SCART == {| class="wikitable" ! style="color:black" | Pin number !! style="color:black" | EURO version !! style="color:black" | JP21 version |- | 1 || - || Audio Left |- | 2 || Audio Right || - |- | 3 || - || GND |- | 4 || GND || GND |- | 5 || GND || Audio Right |- | 6 || Audio Left || - |- | 7 || Video Blue || GND |- | 8 || - || GND |- | 9 || GND || Composite Video / Video Luma |- | 10 || - || - |- | 11 || Video Green || - |- | 12 || - || - |- | 13 || GND || GND |-..."

Main Page

2024-04-30T14:18:38Z

Acid:

Welcome to Medusa Wiki

[[Description]]

[[Using Medusa]]

[[Pinouts]]

[[Menu]]

[[Troubleshooting]]

[[Console]]

[[Recognised Modes]]

[[Sample phase / Pixers per line]]

[[Firmware Update]]

[[Credits]]

Firmware Update

2023-12-14T13:10:29Z

Acid:

== Firmware Update ==

# Check your hardware revision (see [[Description#Hardware_Revisions]]). Beware that firmwares 1.0.18 and older are only compatible with REV A. If you install older firmware on REV B then you may experience some strange behaviour but you won't brick the device and reinstalling correct firmware will be possible and will fix those issues.
# Download firmware from [//medusa-sc.org/firmware/ Medusa Firmwares Page]. Firmware updater is a binary application that will update the firmware automatically. Binaries are available for Linux (64bit binary for Intel), Max OS X (Intel and ARM binaries) and Windows (32bit and 64bit binaries for Intel).
# Make sure that Medusa has been correctly detected by your operating system. Medusa uses standard "virtual serial port" (CDC) protocol on USB, so usually it should work without any drivers on Linux, Macos and Windows 10+. In case of Window 8.1 and older you need this file: [//medusa-sc.org/firmware/medusa.inf medusa.inf] (unsigned file specifically designed for Mesusa) or this file: [//medusa-sc.org/firmware/stmcdc.zip stmcdc.zip] (signed driver for all CDC devices with stm32 chips). See below how to use those files. In case of Linux make sure that your user has permissions to write to serial port (see below).
# Run the application. On the console you should see something like this (typically it takes less than 10 seconds):
<pre>
$ ./firmware_updater_macosx_arm
firmware leng: 170328B
Found port: /dev/cu.usbmodemF2ECEB871
port: /dev/cu.usbmodemF2ECEB871 - main app
Sending fwupdater data
......................................
Sending fwupdater hmac
Found port: /dev/cu.usbmodemF2ECEB871
port: /dev/cu.usbmodemF2ECEB871 - updater
Sending main code data
...................................................................................................................................
Sending main code hmac
Sending fpga core data
........................................................................................................................................................................
Sending fpga core hmac
</pre>

== Using medusa.inf or stmcdc.zip ==

In case of Windows 10 and newer nothing needs to be done and any CDC device is automatically recognized, but in case of older Windows systems the user has to manually assign a driver (usbser.sys in this case) to a specific device (Medusa in this case). By default Medusa is shown in "device manager" as an "unrecognized device". To allow Windows to use usbser.sys you need to:

=== Option 1 - using unsigned medusa.inf file: ===

# go to "device manager" and find Medusa under "other devices";
# right click on it and pick "update driver software..." and then "browse my computer for driver software";
# click the "browse" button and select the catalog with the "medusa.inf" file that you downloaded from this page and then click the "next" button;
# you will see a red warning that the file you are going to use can be dangerous (because this inf file is not signed) - pick "install this driver software anyway".

=== Option 2 - using signed, universal stmcdc.zip file: ===

# unzip the "stmcdc.zip" file;
# go to "device manager" and find Medusa under "other devices";
# right click on it and pick "update driver software..." and then "browse my computer for driver software";
# pick the option "let me pick from a list of available drivers on my computer";
# if windows asks you to choose a device type - just click "next";
# in the next window click on "Have disk...";
# click the "browse" button and select 'stmcdc.inf' in the 'stmcdc' folder;
# click "ok" and then "next";
# Windows will inform you that this driver might not be good for the selected device (because it is a universal driver for all STM32 CDC devices - not specifically for Medusa, but it works perfectly ok) - press the "yes" button.

In both cases you should see a new COM port in your system. In case of using medusa.inf you will see "Medusa CDC serial port" and in case of using stmcdc.zip you will see "STMicroelectronics Virtual COM Port" - it doesn't matter. In both cases the medusa firmware update software should work without any problems.

== Linux udev ==

Usually in Linux default permission to /dev/ttyACMn (device file used to communicate with Medusa) is <code>rw-rw---- root uucp</code>. In such case only root and users belong to uucp group have write access to this file. The first solution is to add your user to 'uucp' group. The second is to add specific 'udev' rule for Medusa that will make sure that all users will have rights to Medusa's port. To do that usually you should create file in '/etc/udev/rules.d/' named '##-medusa.rules' (for example '77-medusa.rules') with following content:
<pre>
SUBSYSTEMS=="usb", ATTRS{idVendor}=="0483", ATTRS{idProduct}=="5740", MODE="0666", SYMLINK+="ttyMedusa"
</pre>
After that you need to reload rules. Typically run the command: <code>sudo udevadm control --reload</code> and then <code>sudo udevadm trigger</code>.

== To brick or not to brick ==

Firmware in Medusa is divided into two parts - a simple updater (let's call it part A) and the main program (call it part B).

Part A updates part B (plus FPGA core) and part B updates part A

The boot code in Medusa checks checksums of both parts. If both checksums are correct then it jumps to part B (or part A when the "right" button is pressed). If only one of them is correct then it jumps to this part directly. This design prevents device "bricking". Even if you loose power during Medusa firmware update, after you turn it back on it will just use the valid part of the firmware. You will only need to run the updater again to complete the procedure.

Firmware Update

2023-12-14T12:55:20Z

Acid: /* Firmware Update */

== Firmware Update ==

# Check your hardware revision (see [[Description#Hardware_Revisions]]). Beware that firmwares 1.0.18 and older are only compatible with REV A. If you install older firmware on REV B then you may experience some strange behaviour but you won't brick the device and reinstalling correct firmware will be possible and will fix those issues.
# Download firmware from [//medusa-sc.org/firmware/ Medusa Firmwares Page]. Firmware updater is a binary application that will update the firmware automatically. Binaries are available for Linux (64bit binary for Intel), Max OS X (Intel and ARM binaries) and Windows (32bit and 64bit binaries for Intel).
# Make sure that Medusa has been correctly detected by your operating system. Medusa uses standard "virtual serial port" (CDC) protocol on USB, so usually it should work without any drivers on Linux, Macos and Windows 10+. In case of Window 8.1 and older you need this file: [//medusa-sc.org/firmware/medusa.inf medusa.inf] (unsigned file specifically designed for Mesusa) or this file: [//medusa-sc.org/firmware/stmcdc.zip stmcdc.zip] (signed driver for all CDC devices with stm32 chips). See below how to use those files. In case of Linux make sure that your user has permissions to write to serial port (see below).
# Run the application. On the console you should see something like this (typically it takes less than 10 seconds):
<pre>
$ ./firmware_updater_macosx_arm
firmware leng: 170328B
Found port: /dev/cu.usbmodemF2ECEB871
port: /dev/cu.usbmodemF2ECEB871 - main app
Sending fwupdater data
......................................
Sending fwupdater hmac
Found port: /dev/cu.usbmodemF2ECEB871
port: /dev/cu.usbmodemF2ECEB871 - updater
Sending main code data
...................................................................................................................................
Sending main code hmac
Sending fpga core data
........................................................................................................................................................................
Sending fpga core hmac
</pre>

== Using medusa.inf or stmcdc.zip ==

In case of Windows 10 and newer nothing needs to be done and any CDC device is automatically recognized, but in case of older Windows systems the user has to manually assign a driver (usbser.sys in this case) to a specific device (Medusa in this case). By default Medusa is shown in "device manager" as an "unrecognized device". To allow Windows to use usbser.sys you need to:

=== Option 1 - using unsigned medusa.inf file: ===

# go to "device manager" and find Medusa under "other devices";
# right click on it and pick "update driver software..." and then "browse my computer for driver software";
# click the "browse" button and select the catalog with the "medusa.inf" file that you downloaded from this page and then click the "next" button;
# you will see a red warning that the file you are going to use can be dangerous (because this inf file is not signed) - pick "install this driver software anyway".

=== Option 2 - using signed, universal stmcdc.zip file: ===

# unzip the "stmcdc.zip" file;
# go to "device manager" and find Medusa under "other devices";
# right click on it and pick "update driver software..." and then "browse my computer for driver software";
# pick the option "let me pick from a list of available drivers on my computer";
# if windows asks you to choose a device type - just click "next";
# in the next window click on "Have disk...";
# click the "browse" button and select 'stmcdc.inf' in the 'stmcdc' folder;
# click "ok" and then "next";
# Windows will inform you that this driver might not be good for the selected device (because it is a universal driver for all STM32 CDC devices - not specifically for Medusa, but it works perfectly ok) - press the "yes" button.

In both cases you should see a new COM port in your system. In case of using medusa.inf you will see "Medusa CDC serial port" and in case of using stmcdc.zip you will see "STMicroelectronics Virtual COM Port" - it doesn't matter. In both cases the medusa firmware update software should work without any problems.

== To brick or not to brick ==

Firmware in Medusa is divided into two parts - a simple updater (let's call it part A) and the main program (call it part B).

Part A updates part B (plus FPGA core) and part B updates part A

The boot code in Medusa checks checksums of both parts. If both checksums are correct then it jumps to part B (or part A when the "right" button is pressed). If only one of them is correct then it jumps to this part directly. This design prevents device "bricking". Even if you loose power during Medusa firmware update, after you turn it back on it will just use the valid part of the firmware. You will only need to run the updater again to complete the procedure.

Firmware Update

2023-11-22T13:07:44Z

Acid: /* Firmware Update */

== Firmware Update ==

# Check your hardware revision (see [[Description#Hardware_Revisions]]). Beware that firmwares 1.0.18 and older are only compatible with REV A. If you install older firmware on REV B then you may experience some strange behaviour but you won't brick the device and reinstalling correct firmware will be possible and will fix those issues.
# Download firmware from [//medusa-sc.org/firmware/ Medusa Firmwares Page]. Firmware updater is a binary application that will update the firmware automatically. Binaries are available for Linux (64bit binary for Intel), Max OS X (Intel and ARM binaries) and Windows (32bit and 64bit binaries for Intel).
# Make sure that Medusa has been correctly detected by your operating system. Medusa uses standard "virtual serial port" (CDC) protocol on USB, so usually it should work without any drivers on Linux, Macos and Windows 10+. In case of Window 8.1 and older you need this file: [//medusa-sc.org/firmware/medusa.inf medusa.inf] (unsigned file specifically designed for Mesusa) or this file: [//medusa-sc.org/firmware/stmcdc.zip stmcdc.zip] (signed driver for all CDC devices with stm32 chips). See below how to use those files.
# Run the application. On the console you should see something like this (typically it takes less than 10 seconds):
<pre>
$ ./firmware_updater_macosx_arm
firmware leng: 170328B
Found port: /dev/cu.usbmodemF2ECEB871
port: /dev/cu.usbmodemF2ECEB871 - main app
Sending fwupdater data
......................................
Sending fwupdater hmac
Found port: /dev/cu.usbmodemF2ECEB871
port: /dev/cu.usbmodemF2ECEB871 - updater
Sending main code data
...................................................................................................................................
Sending main code hmac
Sending fpga core data
........................................................................................................................................................................
Sending fpga core hmac
</pre>

== Using medusa.inf or stmcdc.zip ==

In case of Windows 10 and newer nothing needs to be done and any CDC device is automatically recognized, but in case of older Windows systems the user has to manually assign a driver (usbser.sys in this case) to a specific device (Medusa in this case). By default Medusa is shown in "device manager" as an "unrecognized device". To allow Windows to use usbser.sys you need to:

=== Option 1 - using unsigned medusa.inf file: ===

# go to "device manager" and find Medusa under "other devices";
# right click on it and pick "update driver software..." and then "browse my computer for driver software";
# click the "browse" button and select the catalog with the "medusa.inf" file that you downloaded from this page and then click the "next" button;
# you will see a red warning that the file you are going to use can be dangerous (because this inf file is not signed) - pick "install this driver software anyway".

=== Option 2 - using signed, universal stmcdc.zip file: ===

# unzip the "stmcdc.zip" file;
# go to "device manager" and find Medusa under "other devices";
# right click on it and pick "update driver software..." and then "browse my computer for driver software";
# pick the option "let me pick from a list of available drivers on my computer";
# if windows asks you to choose a device type - just click "next";
# in the next window click on "Have disk...";
# click the "browse" button and select 'stmcdc.inf' in the 'stmcdc' folder;
# click "ok" and then "next";
# Windows will inform you that this driver might not be good for the selected device (because it is a universal driver for all STM32 CDC devices - not specifically for Medusa, but it works perfectly ok) - press the "yes" button.

In both cases you should see a new COM port in your system. In case of using medusa.inf you will see "Medusa CDC serial port" and in case of using stmcdc.zip you will see "STMicroelectronics Virtual COM Port" - it doesn't matter. In both cases the medusa firmware update software should work without any problems.

== To brick or not to brick ==

Firmware in Medusa is divided into two parts - a simple updater (let's call it part A) and the main program (call it part B).

Part A updates part B (plus FPGA core) and part B updates part A

The boot code in Medusa checks checksums of both parts. If both checksums are correct then it jumps to part B (or part A when the "right" button is pressed). If only one of them is correct then it jumps to this part directly. This design prevents device "bricking". Even if you loose power during Medusa firmware update, after you turn it back on it will just use the valid part of the firmware. You will only need to run the updater again to complete the procedure.

Recognised Modes

2023-11-22T12:53:47Z

Acid: /* Modes recognised on RGB input using fingerprint */

== Modes recognised on RGB input using fingerprint ==

* Spectrum familly
** Spectrum 128k
** Spectrum 48k
** Pentagon
* Sinclair QL
* Elwro 800
* Amstrad
** Amstrad CPC
* Commodore 64
** C64 PAL
** C128 RGBI/PAL
* Atari XL/XE
** Atari VBXE PAL
** Atari VBXE DP
** Atari VBXE NTSC
** Atari VBXE DN
* Atari ST
** Atari ST PAL
** Atari ST NTSC
** Atari ST HI
* Atari Falcon
** Atari FALCON VGA (this is standard VGA 640x480 - maybe will be changed in the future)
** Atari FALCON N40
** Atari FALCON N80
** Atari FALCON PAL
* Atari TT
* Atari on MIST
** ATARI Viking
* Amiga OCS
** Amiga PAL
** Amiga NTSC
* Amiga ECS/AGA (without VGAonly)
** Amiga EURO36
** Amiga EURO72
** Amiga SUPER72
** Amiga DblNTSC
** Amiga DblPAL
** Amiga Multiscan
** Amiga SUPERPLUS
** Amiga HIGHGFX
** Amiga HD720
* Amiga ECS/AGA (with VGAonly)
** Amiga DblPAL*
** Amiga DblNTSC*
** Amiga EURO72*
** Amiga Multiscan*
** Amiga SUPER72*
* MIST
** MIST MENU
** MIST QL
** MIST C64 PAL
** MIST C64 NTSC
** MIST C16
** MIST VIC20
** MIST ACORN
** MIST MAC PLUS
* Macintosh (tested on LC475)
** Mac 512x384
** Mac 640x480
** Mac 832x624
** Mac 1024x768
** Mac 1152x870
* Standard VGA
** VGA 800x600
** VGA 80x25TXT@70
** VGA 640x480
* Digital modes
** EGA TXT
** CGA TXT
** MDA TXT
* MSX
** MSX PAL
** MSX NTSC
* SNES
** SNES PAL
** SNES NTSC
* Acorn Archimedes
** ACORN VGA 60Hz
** ACORN PAL-LIKE
** ACORN MULTI (18-21)
** ACORN MULTI (37-40)
** ACORN MULTI (41-43)
** ACORN NTSC-LIKE
** ACORN SVGA
** ACORN VGA 70Hz
** ACORN PAL
* Apple IIc (digital input - work in progress)
** Apple IIc NTSC
** Apple IIc PAL
* Special modes (unrecognised PAL-like and NTSC-like)
** unknown PAL
** unknown NTSC

== Main Menu ==

=== rgb curves ===

This submenu has options for changing RGB curves. By changing these curves it is possible to change brightness, contrast, gamma etc.

* brightness - change screen brightness from -100 to 100
* contrast - change screen contrast from -100 to 100
* blue/yellow - change white balance from -100 to 100
* green/magenta - change white tint from -100 to 100
* gamma - change gamma correction from 0.4 to 2.5
* reset - reset all curves to standard flat 1:1 curves

=== filters ===

This submenu has special picture filters such as green, amber mono monitor, negative, scanline, smoothing etc.

* color - mono monitor emulation with many variants (green,amber,cyan,sepia,red)
* special
** threshold - all values below 128 set to 0 and all values above 127 set to 255 - this is good option for binary signal (ST mono)
** negative - negates all R,G and B values
** 512 colors - round all color values to 512 color palette
** 4096 colors - round all color values to 4096 color palette
** ZX/CPC colors - round all color values to 27 color palette
* pixel
** scanline - every second line made darker (emulates old CRT scanlines)
** pixel mode - every second line and every second column made darker (emulates old LCD displays)
** noise - add noise to picture (emulates connecting to old TV sets)
** sl+noise - scanline + noise
* smoothing - decreases noise. If difference between current pixel and previous is smaller than given value then pixel value is blended with previous pixel - makes picture more even and with less noise. Although you can set it from 0 to 255, using values higher than 10 is not recommended.
* reset - reset all special filters to default values (smoothing to 0 and "no filter" for all other options)

=== shift/size ===

This submenu has options for moving picture left/right, up/down and also for changing window size (you can think of it as an output resolution)

* xshift - move picture left and right (during movement picture may disappear for a moment - it is a normal reaction of the displaying device when something is changing)
* yshift - move picture up and down (same as above - during movement picture may disappear)
* dvi width - set display window to specific width (be aware that some displays do not accept all widths, so during changing for example from 720 to 800 screen may be black when values are in between, also every width change usually means sync lost, so it is better to change these values using OLED, not OSD)
* dvi height - set display window to specific height (same as above)
* dvi presets - beacuse usually we want to use well defined screen sizes, there are presets for screen width and height. When selected preset's height or width is too big for current input resolution, it is lowered to maximum possible value. Current firmware displays only available modes (lower than current native resolution).
** 1280x1024 (mainly for viking mode in MIST)
** 1024x768 (standard old Mac/PC)
** 800x600 (whole screen in PAL modes - with all borders)
** 720x576 (standard PAL resolution - most compatible for PAL modes)
** 720x480 (standard NTSC resolution - most compatible for NTSC modes)
** 640x480 (standard VGA resolution - very compatible)
** 640x400 (good for ST mono)

=== rgb only ===

This submenu has options that are used only when picture is processed by RGB A/D converter (front LED is red, on OLED info says that source of signal is RGB "RGB: xxxxxxx"). In current firmware this menu is only visible when RGB signal is processed.

[[File:sample_phase.png|200px|thumb|sample phase]]

* sample phase - sets sample phase of pixel. Pixels have to pe sampled in "the middle of the pixel". When pixels are sampled "in between" then the picture looks blurry and often noisy. This option should be adjusted individually for every device connected to Medusa - this is a very important option !!!.
* pixels/line - for all recognised modes this option shouldn't be adjusted - for all known computers this parameter is predefined in Medusa, but when you connect something that is not recognised ("unknown PAL", "unknown NTSC", "unrecognised lo" or "unrecognised hi") you can set this option to improve picture quality.
* double res - doubles X resolution (practically useful only for Amiga's "Super Hires" modes)
* double lines - doubles Y resolution (standard for PAL/NTSC modes)
* auto levels - runs a routine, that tries to find best offset and gain for R, G and B signals - use it, when the picture is too dark or too light - usually it is automatically performed whenever you connect a specific device for the first time, but if you have two cables for the same computer then after a cable change you may need to run this manually.
* component mode - changes R,G,B to Y,Cr,Cb (Y on green, Cr on red and Cb on blue) - after changing this option "auto levels" is always re-run
** when active source is VGA
*** RGB mode - standard RGB
*** YCrCb - Y on green, Cr on red and Cb on blue)
*** Mono on G - use green only as a mono signal, ignore red and blue
** when active source is SCART
*** YCrCb [Y<-CV] - Y on CV SCART pin, Cr on red, Cb on blue)
*** YCrCb [Y<-G] - Y on green, Cr on red, Cb on blue)
*** Mono [Y<-CV] - use CV as a mono signal, ignore red, green and blue signals
*** Mono [Y<-G] - use green as a mono signal, CV as a synchro input, ignore red and blue
*** Hybrid mode - Special S-Video mode. Process luma signal by RGB A/D and chroma by SDTV A/D. Experimental mode that increases S-Video quality.
* digital mode (only when digital signal is processed) - switching between MDA/Hercules, RGBI/C128/CGA and EGA
* lowpass filter (switch on/off lowpass filter in RGB A/D and external SCART-only LP filter)
* luma delay (only when hybrid mode is active) - adjust chroma/luma shift
* fingerprint - Medusa recognises input devices using "fingerprint" mechanism. For each device there is a predefined fingerprint in the firmware. But sometimes it may happen that your device is not recognised correctly, or it is not in Medusa's database at all. This option displays fingerprint parameters for currently connected device. These values may be used by Medusa developers to improve devices detection and adding new ones.

=== global options ===

This submenu has global options (DVI, timeouts, audio freq itp.)

* DVI mode
** auto - automatically detect if the receiver is capable of audio processing.
** extended DVI - always send audio packets on DVI (not compatible with DVI, but usually recognised correctly by HDMI devices connected to Medusa via appropriate cables)
** pure DVI - pure DVI signal without audio (compatible with most old LCD 17" and 19" displays)
* DVI extras (only in extended DVI mode)
** audio only - send only audio packets
** audio + info - send audio and info packets
* SCART mode
** auto - switch between RGB/SDTV automatically (using SWITCH pin on SCART)
** sdtv only - always process signal using SDTV A/D (composite video / s-video)
** rgb only - always process signal using RGB A/D
* SDTV mode
** auto - automatically recognise CVBS (composite video) and S-Video
** force CVBS - process signal as composite video (luma and chroma together)
** force S-Video - process signal as S-Video (luma / chroma separated)
* Audio source
** auto - use SCART as an audio source when it is used as a video source, and 3.5" jack otherwise
** SCART only - always use SCART as an audio input
** Jack only - always use 3.5" Jack as an audio input
** SCART + Jack (rev B only) - mix signals from SCART and Jack.
* Aud mix ratio (only when SCART + Jack is selected) - switch mix ratio 1:7,2:6,3:5,4:4,5:3,6:2,7:1
* OLED rotation - optionally rotate OLED content
* Audio freq (rev B only and only in extended DVI mode) - change audio sample frequency (192,176.4,96,88.2,48,44.1,32) kHz
* Audio bits (only in extended DVI mode) - change audio sample bit depth (24,20,16) bits
* No Signal FPS - change "no signal screen" mode (50Hz/60Hz)
* Lost sync wait
* Sleep timeout
* OSD timeouts
** main menu
** sub menus
** start info
** change mode
** no signal
** return to top

=== reset ===

Reset settings (all settings are also reset when you turn on Medusa with pressed both left keys - 'up' and 'down')

* rst glob opts - resets only global options (DVI mode and OSD timeouts)
* rst curr prof - resets current profile (all curves, filters, etc. only for currently connected device)
* factory reset - same as running with 'up' and 'down' pressed - clears whole flash memory with all settings

== Main Menu ==

=== rgb curves ===

This submenu has options for changing RGB curves. By changing these curves it is possible to change brightness, contrast, gamma etc.

* brightness - change screen brightness from -100 to 100
* contrast - change screen contrast from -100 to 100
* blue/yellow - change white balance from -100 to 100
* green/magenta - change white tint from -100 to 100
* gamma - change gamma correction from 0.4 to 2.5
* reset - reset all curves to standard flat 1:1 curves

=== filters ===

This submenu has special picture filters such as green, amber mono monitor, negative, scanline, smoothing etc.

* color - mono monitor emulation with many variants (green,amber,cyan,sepia,red)
* special
** threshold - all values below 128 set to 0 and all values above 127 set to 255 - this is good option for binary signal (ST mono)
** negative - negates all R,G and B values
** 512 colors - round all color values to 512 color palette
** 4096 colors - round all color values to 4096 color palette
** ZX/CPC colors - round all color values to 27 color palette
* pixel
** scanline - every second line made darker (emulates old CRT scanlines)
** pixel mode - every second line and every second column made darker (emulates old LCD displays)
** noise - add noise to picture (emulates connecting to old TV sets)
** sl+noise - scanline + noise
* smoothing - decreases noise. If difference between current pixel and previous is smaller than given value then pixel value is blended with previous pixel - makes picture more even and with less noise. Although you can set it from 0 to 255, using values higher than 10 is not recommended.
* reset - reset all special filters to default values (smoothing to 0 and "no filter" for all other options)

=== shift/size ===

This submenu has options for moving picture left/right, up/down and also for changing window size (you can think of it as an output resolution)

* xshift - move picture left and right (during movement picture may disappear for a moment - it is a normal reaction of the displaying device when something is changing)
* yshift - move picture up and down (same as above - during movement picture may disappear)
* dvi width - set display window to specific width (be aware that some displays do not accept all widths, so during changing for example from 720 to 800 screen may be black when values are in between, also every width change usually means sync lost, so it is better to change these values using OLED, not OSD)
* dvi height - set display window to specific height (same as above)
* dvi presets - beacuse usually we want to use well defined screen sizes, there are presets for screen width and height. When selected preset's height or width is too big for current input resolution, it is lowered to maximum possible value. Current firmware displays only available modes (lower than current native resolution).
** 1280x1024 (mainly for viking mode in MIST)
** 1024x768 (standard old Mac/PC)
** 800x600 (whole screen in PAL modes - with all borders)
** 720x576 (standard PAL resolution - most compatible for PAL modes)
** 720x480 (standard NTSC resolution - most compatible for NTSC modes)
** 640x480 (standard VGA resolution - very compatible)
** 640x400 (good for ST mono)

=== rgb only ===

This submenu has options that are used only when picture is processed by RGB A/D converter (front LED is red, on OLED info says that source of signal is RGB "RGB: xxxxxxx"). In current firmware this menu is only visible when RGB signal is processed.

[[File:sample_phase.png|200px|thumb|sample phase]]

* sample phase - sets sample phase of pixel. Pixels have to pe sampled in "the middle of the pixel". When pixels are sampled "in between" then the picture looks blurry and often noisy. This option should be adjusted individually for every device connected to Medusa - this is a very important option !!!.
* pixels/line - for all recognised modes this option shouldn't be adjusted - for all known computers this parameter is predefined in Medusa, but when you connect something that is not recognised ("unknown PAL", "unknown NTSC", "unrecognised lo" or "unrecognised hi") you can set this option to improve picture quality.
* double res - doubles X resolution (practically useful only for Amiga's "Super Hires" modes)
* double lines - doubles Y resolution (standard for PAL/NTSC modes)
* auto levels - runs a routine, that tries to find best offset and gain for R, G and B signals - use it, when the picture is too dark or too light - usually it is automatically performed whenever you connect a specific device for the first time, but if you have two cables for the same computer then after a cable change you may need to run this manually.
* component mode - changes R,G,B to Y,Cr,Cb (Y on green, Cr on red and Cb on blue) - after changing this option "auto levels" is always re-run
** when active source is VGA
*** RGB mode - standard RGB
*** YCrCb - Y on green, Cr on red and Cb on blue)
*** Mono on G - use green only as a mono signal, ignore red and blue
** when active source is SCART
*** YCrCb [Y<-CV] - Y on CV SCART pin, Cr on red, Cb on blue)
*** YCrCb [Y<-G] - Y on green, Cr on red, Cb on blue)
*** Mono [Y<-CV] - use CV as a mono signal, ignore red, green and blue signals
*** Mono [Y<-G] - use green as a mono signal, CV as a synchro input, ignore red and blue
*** Hybrid mode - Special S-Video mode. Process luma signal by RGB A/D and chroma by SDTV A/D. Experimental mode that increases S-Video quality.
* digital mode (only when digital signal is processed) - switching between MDA/Hercules, RGBI/C128/CGA and EGA
* lowpass filter (switch on/off lowpass filter in RGB A/D and external SCART-only LP filter)
* luma delay (only when hybrid mode is active) - adjust chroma/luma shift
* fingerprint - Medusa recognises input devices using "fingerprint" mechanism. For each device there is a predefined fingerprint in the firmware. But sometimes it may happen that your device is not recognised correctly, or it is not in Medusa's database at all. This option displays fingerprint parameters for currently connected device. These values may be used by Medusa developers to improve devices detection and adding new ones.

=== global options ===

This submenu has global options (DVI modes, OSD timeouts)

* DVI mode
** pure DVI - pure DVI signal without audio (compatible with most old LCD 17" and 19" displays)
** DVI with audio - adds audio packets to DVI signal which is not compatible with DVI, but usually recognised correctly by HDMI devices connected to Medusa via appropriate cables.
* OSD timeouts
** main menu
** sub menus
** start info
** change mode
** no signal
** return to top

=== reset ===

Reset settings (all settings are also reset when you turn on Medusa with pressed both left keys - 'up' and 'down')

* rst glob opts - resets only global options (DVI mode and OSD timeouts)
* rst curr prof - resets current profile (all curves, filters, etc. only for currently connected device)
* factory reset - same as running with 'up' and 'down' pressed - clears whole flash memory with all settings

== Main Menu ==

=== rgb curves ===

This submenu has options for changing RGB curves. By changing these curves it is possible to change brightness, contrast, gamma etc.

* brightness - change screen brightness from -100 to 100
* contrast - change screen contrast from -100 to 100
* blue/yellow - change white balance from -100 to 100
* green/magenta - change white tint from -100 to 100
* gamma - change gamma correction from 0.4 to 2.5
* reset - reset all curves to standard flat 1:1 curves

=== filters ===

This submenu has special picture filters such as green, amber mono monitor, negative, scanline, smoothing etc.

* color - mono monitor emulation with many variants (green,amber,cyan,sepia,red)
* special
** threshold - all values below 128 set to 0 and all values above 127 set to 255 - this is good option for binary signal (ST mono)
** negative - negates all R,G and B values
** 512 colors - round all color values to 512 color palette
** 4096 colors - round all color values to 4096 color palette
** ZX/CPC colors - round all color values to 27 color palette
* pixel
** scanline - every second line made darker (emulates old CRT scanlines)
** pixel mode - every second line and every second column made darker (emulates old LCD displays)
** noise - add noise to picture (emulates connecting to old TV sets)
** sl+noise - scanline + noise
* smoothing - decreases noise. If difference between current pixel and previous is smaller than given value then pixel value is blended with previous pixel - makes picture more even and with less noise. Although you can set it from 0 to 255, using values higher than 10 is not recommended.
* reset - reset all special filters to default values (smoothing to 0 and "no filter" for all other options)

=== shift/size ===

This submenu has options for moving picture left/right, up/down and also for changing window size (you can think of it as an output resolution)

* xshift - move picture left and right (during movement picture may disappear for a moment - it is a normal reaction of the displaying device when something is changing)
* yshift - move picture up and down (same as above - during movement picture may disappear)
* dvi width - set display window to specific width (be aware that some displays do not accept all widths, so during changing for example from 720 to 800 screen may be black when values are in between, also every width change usually means sync lost, so it is better to change these values using OLED, not OSD)
* dvi height - set display window to specific height (same as above)
* dvi presets - beacuse usually we want to use well defined screen sizes, there are presets for screen width and height. When selected preset's height or width is too big for current input resolution, it is lowered to maximum possible value. Current firmware displays only available modes (lower than current native resolution).
** 1280x1024 (mainly for viking mode in MIST)
** 1024x768 (standard old Mac/PC)
** 800x600 (whole screen in PAL modes - with all borders)
** 720x576 (standard PAL resolution - most compatible for PAL modes)
** 720x480 (standard NTSC resolution - most compatible for NTSC modes)
** 640x480 (standard VGA resolution - very compatible)
** 640x400 (good for ST mono)

=== rgb only ===

This submenu has options that are used only when picture is processed by RGB A/D converter (front LED is red, on OLED info says that source of signal is RGB "RGB: xxxxxxx")

[[File:sample_phase.png|200px|thumb|sample phase]]

* sample phase - sets sample phase of pixel. Pixels have to pe sampled in "the middle of the pixel". When pixels are sampled "in between" then the picture looks blurry and often noisy. This option should be adjusted individually for every device connected to Medusa - this is a very important option !!!.
* pixels/line - for all recognised modes this option shouldn't be adjusted - for all known computers this parameter is predefined in Medusa, but when you connect something that is not recognised ("unknown PAL", "unknown NTSC", "unrecognised lo" or "unrecognised hi") you can set this option to improve picture quality.
* double res - doubles X resolution (practically useful only for Amiga's "Super Hires" modes)
* auto levels - runs a routine, that tries to find best offset and gain for R, G and B signals - use it, when the picture is too dark or too light - usually it is automatically performed whenever you connect a specific device for the first time, but if you have two cables for the same computer then after a cable change you may need to run this manually.
* component mode - changes R,G,B to Y,Cr,Cb (Y on green, Cr on red and Cb on blue) - after changing this option "auto levels" is always re-run
* fingerprint - Medusa recognises input devices using "fingerprint" mechanism. For each device there is a predefined fingerprint in the firmware. But sometimes it may happen that your device is not recognised correctly, or it is not in Medusa's database at all. This option displays fingerprint parameters for currently connected device. These values may be used by Medusa developers to improve devices detection and adding new ones.

=== global options ===

This submenu has global options (DVI modes, OSD timeouts)

* DVI mode
** pure DVI - pure DVI signal without audio (compatible with most old LCD 17" and 19" displays)
** DVI with audio - adds audio packets to DVI signal which is not compatible with DVI, but usually recognised correctly by HDMI devices connected to Medusa via appropriate cables.
* OSD timeouts
** main menu
** sub menus
** start info
** change mode
** no signal
** return to top

=== reset ===

Reset settings (all settings are also reset when you turn on Medusa with pressed both left keys - 'up' and 'down')

* rst glob opts - resets only global options (DVI mode and OSD timeouts)
* rst curr prof - resets current profile (all curves, filters, etc. only for currently connected device)
* factory reset - same as running with 'up' and 'down' pressed - clears whole flash memory with all settings

Description

2023-11-22T11:48:34Z

Acid:

== What is Medusa ? ==

Medusa is a device that allows connecting of old computers to modern display devices (monitors, projectors etc.).

== Hardware Revisions ==

* REV A (first hardware version)

[[File:Medusa_REVA_top.jpg|640px|frameless|REV A]]

* REV B (second hardware version)
** new db9 socket - 8bit digital input. Ready for supporting C128, CGA, EGA, Apple IIc and others
** moved audio source switching from CPU to FPGA - gives ability to mix both channels using PWM
** added new PLL to generate audio sample frequency (switching between 32k, 44.1k, 48k, 96k, 192k etc.)
** better op-amp that drives audio output jack socket (32ohm headphones can be connected directly, also better audio quality)
** lowered digital audio amplitude (cleaner, not overdriven audio over DVI)
** 5V voltage on DVI passed through Schottky diode (prevents powering Medusa from DVI)
** better input protection on SCART socket (better protection of fragile NCS2564)

[[File:Medusa_REVB_top.jpg|640px|frameless|REV B]]

== A Little History ==

When first home computers appeared, people didn't have special computer monitors in their homes, but almost everybody had a standard TV set. This is why first home computers (such as ZX Spectrum, Atari, Commodore) were designed to be connected to standard TV sets. In these times there were different color encoding standards - mainly NTSC, PAL and SECAM. Main differences between those standards were screen refresh rate (60fps for NTSC, 50fps for PAL and SECAM) and way of color signal encoding, but one thing was common: horizontal refresh rate (about 15kHz in all standards). These two values - horizontal refresh rate and screen or vertical refresh rate - define number of lines per screen and therefore maximum vertical resolution. In 50fps systems there were about 312 lines per screen and in 60fps systems even less (about 262 lines). In times of 8-bit computers resolution such as 320x200 was considered "hi-res", so it was absolutely enough. In 16-bit computers it was still ok but users started to want more. Atari, for its Atari ST model, introduced a special hi-res monitor (with 70fps and about 31.5kHz horizontal refresh rate, with resolution 640x400), in PC's they introduced EGA standard (21.8kHz and resolutions up to 640x350), and couple years later VGA with 31.5kHz horizontal refresh rate. At the beginning every video standard (computer or graphic card) needed a dedicated monitor. The problem was that users didn't want to buy a new monitor every time they changed their graphics adapter. In 1989 in America VESA organisation was incorporated to introduce video standards. The only problem was that when they started defining their standards, there existed already Super VGA with resolution of 800x600 and nobody wanted to use old 15kHz resolutions anymore. Therefore the lowest available "standard" resolution defined by VESA was 640x350 with horizontal refresh rate 31.5kHz, so this was the lowest horizontal refresh rate accepted by almost all monitors. The other problem is also vertical (or screen) refresh rate. Minimal refresh rate defined by VESA is 60Hz (60fps). This is why most modern monitors don't accept lower horizontal refresh rate than 31.5kHz. With vertical refresh rate it is a bit better, because introduction of HDMI compatibility, with its TV standards, forced 50Hz, so the majority of monitors that have a HDMI port should accept 50Hz.

== Problems with old computers ==

As you can see when one wants to connect an old computer to a modern display, one can encounter problems like:

* color decoding in PAL/NTSC signal (in case of Composite Video or S-Video signal),
* finding exact pixel clock frequency,
* double horizontal refresh rate (when we double 15.5kHz we are close enough to be accepted by modern displays),
* some modern displays don't have analog input - only digital.

== Solution ==

* The first problem to solve is decoding PAL or NTSC signal (some old computers don't have RGB output). To achieve that Medusa uses specialised video decoder, an integrated circuit created by Analog Devices, that can sample and decode SDTV signal (PAL, NTSC or even SECAM).

* The second problem is to find the exact pixel clock for the input signal (for RGB signals). There are no ultimate solution for this. In Medusa you can always manually define number of pixels per line, but to achieve that more automatically we measure a specific signal "fingerprint" (based on synchro signals) and pick one from dozens of available pre-set options.

* The third problem is to double the horizontal refresh rate. To achieve that every line from input is put into a small memory block inside an FPGA chip and then emitted twice. This is why sometimes we call such devices "scan doublers". This is of course done only when necessary (input horizontal refresh rate is lower than 31kHz).

* The last problem is to output a signal in digital form. In Medusa we decided to use DVI-I standard. DVI standard is theoretically obsoleted by HDMI, but since HDMI is licensed and DVI not, we decided to use DVI. Also DVI in full version (which is implemented in Medusa) also outputs all signals in analog format. This is very convenient because it allows the use of older 17" and 19" LCD panels, that are very cheap and have better screen proportions for old computers than new TV's. At the same time, using a simple cable, one can also connect it to an HDMI device.

== Why Medusa? ==

This is actually a very good question. There are a lot of devices that do similar things. The only problem is ... I've tried almost all of them (FrameMeister included). They all lacked something.

* Cheap Chinese devices use chips designed for TV's, with a lot of features that are good in case of movies but unacceptable in case of computers (few frames of latency). Also picture quality is horrible - RGB signal is sampled with constant ratio - not in sync with original pixels. They can't accept anything other than PAL or NTSC-like signals (forget about ST-mono or Amiga-AGA funny resolutions).

* FrameMeister - a very good device, but expensive. It also accepts only PAL and NTSC-like resolution (no ST-mono etc.).

* OSSC - also a very good device, but without composite video and s-video inputs. Only good for RGB signals. Tough to configure.

So what can Medusa do?

* Accept CVBS signal (Composite Video) on SCART (or JP21 - special JP21 version)
* Accept S-Video signal on SCART (or JP21)
* Accept RGB signal on SCART or VGA input (with more than 50 predefined settings for popular old computers; it can work not only with ST-mono, but also Viking card emulated by MIST - yes 1280x1024 !!!; more modes will be added with future firmware updates)
* Encode audio on DVI; this option can be switched on and (using DVI-HDMI adapter and HDMI capable display) audio signal from SCART (or 3.5mm jack) is digitised and mixed with video
* Allows user to change a lot of settings on the fly using OSD or built-in OLED display (settings such as contrast, brightness, X/Y picture shift etc.).
* Output signal analog and digital at the same time on DVI-I, so it can be connected both to old VGA monitors (also CRT ones) as well as modern HDMI monitors or TV's.
* Easy firmware update (no special device is needed - just connect Medusa via USB to a computer and run binary updater - available for Win,Linux,MacOS)

Why Medusa is not perfect? :)

Because a perfect solution does not exist. Medusa doesn't change vertical refresh rate, so if your monitor can't accept 50Hz then it will not display video from Medusa. Most monitors with HDMI inputs are able to display 50Hz (because of TV standards), but that's not not always the case with old VGA LCD panels. I have good experiences with LG's and NEC's, but can't guarantee that a particular monitor will accept 50Hz. Probably at some point we will prepare a list of monitors that can do that. With such approach to screen conversion (simple line doubling) any resolution change on input will also lead to resolution change on output. Even small change will usually cause a black screen on the displaying device (for about 0.5 - 1 second). This is normal - this is how displaying devices work. The only way to circumvent that would be to constantly display a picture in a chosen resolution (for example 1920x1080@60) and sample pixels from input and put them in a displayed framebuffer. But in this approach a lot of problems would occur. For example all 50Hz scrolls would be jagged. This is why we decided not to do that. Also the device would be much more expensive.

== Internals of Medusa ==

[[File:Medusa_internals.png|851px|frameless|block diagram of Medusa]]

File:Medusa REVB top.jpg

2023-11-22T11:38:55Z

Acid:

File:Medusa REVA top.jpg

2023-11-22T11:38:32Z

Acid:

Firmware Update

2023-03-02T14:40:42Z

Acid: /* Using medusa.inf or stmcdc.zip */

== Firmware Update ==

# Download firmware from [//medusa-sc.org/firmware/ Medusa Firmwares Page]. Firmware updater is a binary application that will update the firmware automatically. Binaries are available for Linux (64bit binary for Intel), Max OS X (Intel and ARM binaries) and Windows (32bit and 64bit binaries for Intel).
# Make sure that Medusa has been correctly detected by your operating system. Medusa uses standard "virtual serial port" (CDC) protocol on USB, so usually it should work without any drivers on Linux, Macos and Windows 10+. In case of Window 8.1 and older you need this file: [//medusa-sc.org/firmware/medusa.inf medusa.inf] (unsigned file specifically designed for Mesusa) or this file: [//medusa-sc.org/firmware/stmcdc.zip stmcdc.zip] (signed driver for all CDC devices with stm32 chips). See below how to use those files.
# Run the application. On the console you should see something like this (typically it takes less than 10 seconds):
<pre>
$ ./firmware_updater_macosx_arm
firmware leng: 170328B
Found port: /dev/cu.usbmodemF2ECEB871
port: /dev/cu.usbmodemF2ECEB871 - main app
Sending fwupdater data
......................................
Sending fwupdater hmac
Found port: /dev/cu.usbmodemF2ECEB871
port: /dev/cu.usbmodemF2ECEB871 - updater
Sending main code data
...................................................................................................................................
Sending main code hmac
Sending fpga core data
........................................................................................................................................................................
Sending fpga core hmac
</pre>

== Using medusa.inf or stmcdc.zip ==

In case of Windows 10 and newer nothing needs to be done and any CDC device is automatically recognized, but in case of older Windows systems the user has to manually assign a driver (usbser.sys in this case) to a specific device (Medusa in this case). By default Medusa is shown in "device manager" as an "unrecognized device". To allow Windows to use usbser.sys you need to:

=== Option 1 - using unsigned medusa.inf file: ===

# go to "device manager" and find Medusa under "other devices";
# right click on it and pick "update driver software..." and then "browse my computer for driver software";
# click the "browse" button and select the catalog with the "medusa.inf" file that you downloaded from this page and then click the "next" button;
# you will see a red warning that the file you are going to use can be dangerous (because this inf file is not signed) - pick "install this driver software anyway".

=== Option 2 - using signed, universal stmcdc.zip file: ===

# unzip the "stmcdc.zip" file;
# go to "device manager" and find Medusa under "other devices";
# right click on it and pick "update driver software..." and then "browse my computer for driver software";
# pick the option "let me pick from a list of available drivers on my computer";
# if windows asks you to choose a device type - just click "next";
# in the next window click on "Have disk...";
# click the "browse" button and select 'stmcdc.inf' in the 'stmcdc' folder;
# click "ok" and then "next";
# Windows will inform you that this driver might not be good for the selected device (because it is a universal driver for all STM32 CDC devices - not specifically for Medusa, but it works perfectly ok) - press the "yes" button.

In both cases you should see a new COM port in your system. In case of using medusa.inf you will see "Medusa CDC serial port" and in case of using stmcdc.zip you will see "STMicroelectronics Virtual COM Port" - it doesn't matter. In both cases the medusa firmware update software should work without any problems.

== To brick or not to brick ==

Firmware in Medusa is divided into two parts - a simple updater (let's call it part A) and the main program (call it part B).

Part A updates part B (plus FPGA core) and part B updates part A

The boot code in Medusa checks checksums of both parts. If both checksums are correct then it jumps to part B (or part A when the "right" button is pressed). If only one of them is correct then it jumps to this part directly. This design prevents device "bricking". Even if you loose power during Medusa firmware update, after you turn it back on it will just use the valid part of the firmware. You will only need to run the updater again to complete the procedure.

Firmware Update

2023-03-02T14:39:37Z

Acid:

== Firmware Update ==

# Download firmware from [//medusa-sc.org/firmware/ Medusa Firmwares Page]. Firmware updater is a binary application that will update the firmware automatically. Binaries are available for Linux (64bit binary for Intel), Max OS X (Intel and ARM binaries) and Windows (32bit and 64bit binaries for Intel).
# Make sure that Medusa has been correctly detected by your operating system. Medusa uses standard "virtual serial port" (CDC) protocol on USB, so usually it should work without any drivers on Linux, Macos and Windows 10+. In case of Window 8.1 and older you need this file: [//medusa-sc.org/firmware/medusa.inf medusa.inf] (unsigned file specifically designed for Mesusa) or this file: [//medusa-sc.org/firmware/stmcdc.zip stmcdc.zip] (signed driver for all CDC devices with stm32 chips). See below how to use those files.
# Run the application. On the console you should see something like this (typically it takes less than 10 seconds):
<pre>
$ ./firmware_updater_macosx_arm
firmware leng: 170328B
Found port: /dev/cu.usbmodemF2ECEB871
port: /dev/cu.usbmodemF2ECEB871 - main app
Sending fwupdater data
......................................
Sending fwupdater hmac
Found port: /dev/cu.usbmodemF2ECEB871
port: /dev/cu.usbmodemF2ECEB871 - updater
Sending main code data
...................................................................................................................................
Sending main code hmac
Sending fpga core data
........................................................................................................................................................................
Sending fpga core hmac
</pre>

== Using medusa.inf or stmcdc.zip ==

In case of Windows 10 and newer nothing needs to be done and any CDC device is automatically recognized, but in case of older Windows systems the user has to manually assign a driver (usbser.sys in this case) to a specific device (Medusa in this case). By default Medusa is shown in "device manager" as an "unrecognized device". To allow Windows to use usbser.sys you need to:

=== Option 1 - using unsigned medusa.inf file: ===

# go to "device manager" and find Medusa under "other devices";
# right click on it and pick "update driver software..." and then "browse my computer for driver software";
# click the "browse" button and select the catalog with the "medusa.inf" file that you downloaded from this page and then click the "next" button;
# you will see a red warning that the file you are going to use can be dangerous (because this inf file is not signed) - pick "install this driver software anyway".

=== Option 2 - using signed, universal stmcdc.zip file: ===

# unzip the "stmcdc.zip" file;
# go to "device manager" and find Medusa under "other devices";
# right click on it and pick "update driver software..." and then "browse my computer for driver software";
# pick the option "let me pick from a list of available drivers on my computer";
# if windows asks you to choose a device type - just click "next";
# in the next window click on "Have disk...";
# click the "browse" button and select 'stmcdc.inf' in the 'stmcdc' folder;
# click "ok" and then "next";
# Windows will inform you that this driver might not be good for the selected device (because it is a universal driver for all STM32 CDC devices - not specifically for Medusa, but it works perfectly ok) - press the "yes" button.

In both cases you should see a new COM port in your system. In case of using medusa.inf you will see "Medusa CDC serial port" and in case of using stmcdc.zip you will see "STMicroelectronics Virtual COM Port" - it doesn't matter. In both cases the medusa firmware update software should now work without any problems.

== To brick or not to brick ==

Firmware in Medusa is divided into two parts - a simple updater (let's call it part A) and the main program (call it part B).

Part A updates part B (plus FPGA core) and part B updates part A

The boot code in Medusa checks checksums of both parts. If both checksums are correct then it jumps to part B (or part A when the "right" button is pressed). If only one of them is correct then it jumps to this part directly. This design prevents device "bricking". Even if you loose power during Medusa firmware update, after you turn it back on it will just use the valid part of the firmware. You will only need to run the updater again to complete the procedure.

Firmware Update

2023-02-26T17:21:51Z

Acid:

== Firmware Update ==

# Download firmware from [//medusa-sc.org/firmware/ Medusa Firmwares Page]. Firmware updater is a binary application that will update the firmware automatically. Binaries are available for Linux (64bit binary for Intel), Max OS X (Intel and ARM binaries) and Windows (32bit and 64bit binaries for Intel).
# Make sure that Medusa has been correctly detected by your operating system. Medusa uses standard "virtual serial port" (CDC) protocol on USB, so usually it should work without any drivers on Linux, Macos and Windows 10+. In case of Window 8.1 and older you need this file: [//medusa-sc.org/firmware/medusa.inf medusa.inf] (unsigned file specifically designed for Mesusa) or this file: [//medusa-sc.org/firmware/stmcdc.zip stmcdc.zip] (signed driver for all CDC devices with stm32 chips). See below how to use those files.
# Run the application. On the console you should see something like this (typically it takes less than 10 seconds):
<pre>
$ ./firmware_updater_macosx_arm
firmware leng: 170328B
Found port: /dev/cu.usbmodemF2ECEB871
port: /dev/cu.usbmodemF2ECEB871 - main app
Sending fwupdater data
......................................
Sending fwupdater hmac
Found port: /dev/cu.usbmodemF2ECEB871
port: /dev/cu.usbmodemF2ECEB871 - updater
Sending main code data
...................................................................................................................................
Sending main code hmac
Sending fpga core data
........................................................................................................................................................................
Sending fpga core hmac
</pre>

== Using medusa.inf or stmcdc.zip ==

In case of Windows 10 and newer nothing needs to be done and any CDC device is automatically recognized, but in case of older Windows systems user has to manually assign driver (usbser.sys in this case) to specific device (Medusa in this case). By default Medusa in "device manager" is shown as an "unrecognized device". To allow Windows to use usbser.sys you need to:

=== Option 1 - using unsigned medusa.inf file ===

# go to "device manager" and find Medusa under "other devices" with yellow exclamation mark on it.
# right click on it and pick "update driver software..." and then "browse my computer for driver software"
# click "browse" button and select catalog with "medusa.inf" file that you downloaded from this page and then click "next" button
# you see red warning that file you are going to use can be dangerous (because this inf file is not signed) - pick "install this driver software anyway"

=== Option 2 - using signed, universal stmcdc.zip file ===

# unzip stmcdc.zip file
# go to "device manager" and find Medusa under "other devices" with yellow exclamation mark on it.
# right click on it and pick "update driver software..." and then "browse my computer for driver software"
# pick option "let me pick from a list of available drivers on my computer"
# if windows asks you to choose device type - just click "next"
# In next window click on "Have disk..."
# click "browse" button and select 'stmcdc.inf' in 'stmcdc' folder.
# Then click "ok" and then "next".
# Windows will inform you that this driver might not be good for given device (because it is universal driver for all STM CDC devices - not specifically for Medusa, but it works perfectly ok) - press "yes" button

In both cases you should see new COM port in your system. In case of using medusa.inf you will see "Medusa CDC serial port" and in case of using stmcdc.zip you will see "STMicroelectronics Virtual COM Port" - it doesn't matter. In both cases medusa firmware update software should work now without any problems.

== To brick or not to brick ==

Firmware in Medusa is divided into two parts - simple updater (let's call it part A) and the main program (call it part B).

Part A updates part B (plus FPGA core) and part B updates part A

Boot code in Medusa checks checksums for both parts. If both checksums are correct then it jumps to part B (or part A when "right" button is pressed). If only one of them is correct then it jumps to this part directly. This design prevents device "bricking". Even you loose power during Medusa firmware update, after you turn it back on it will just use the valid part of the firmware. You will only need to run the updater again to complete the procedure.

Firmware Update

2023-02-26T16:18:28Z

Acid: /* Firmware Update */

Firmware Update

2023-02-26T16:16:06Z

Acid: /* Firmware Update */

File:Medusa internals.png

2022-07-11T12:46:38Z

Acid: Acid uploaded a new version of File:Medusa internals.png

Description

2022-07-11T12:43:52Z

Acid: /* Internals of Medusa */

== What is Medusa ? ==

Medusa is a device that allows connecting of old computers to modern display devices (monitors, projectors etc.).

== A Little History ==

When first home computers appeared, people didn't have special computer monitors in their homes, but almost everybody had a standard TV set. This is why first home computers (such as ZX Spectrum, Atari, Commodore) were designed to be connected to standard TV sets. In these times there were different color encoding standards - mainly NTSC, PAL and SECAM. Main differences between those standards were screen refresh rate (60fps for NTSC, 50fps for PAL and SECAM) and way of color signal encoding, but one thing was common: horizontal refresh rate (about 15kHz in all standards). These two values - horizontal refresh rate and screen or vertical refresh rate - define number of lines per screen and therefore maximum vertical resolution. In 50fps systems there were about 312 lines per screen and in 60fps systems even less (about 262 lines). In times of 8-bit computers resolution such as 320x200 was considered "hi-res", so it was absolutely enough. In 16-bit computers it was still ok but users started to want more. Atari, for its Atari ST model, introduced a special hi-res monitor (with 70fps and about 31.5kHz horizontal refresh rate, with resolution 640x400), in PC's they introduced EGA standard (21.8kHz and resolutions up to 640x350), and couple years later VGA with 31.5kHz horizontal refresh rate. At the beginning every video standard (computer or graphic card) needed a dedicated monitor. The problem was that users didn't want to buy a new monitor every time they changed their graphics adapter. In 1989 in America VESA organisation was incorporated to introduce video standards. The only problem was that when they started defining their standards, there existed already Super VGA with resolution of 800x600 and nobody wanted to use old 15kHz resolutions anymore. Therefore the lowest available "standard" resolution defined by VESA was 640x350 with horizontal refresh rate 31.5kHz, so this was the lowest horizontal refresh rate accepted by almost all monitors. The other problem is also vertical (or screen) refresh rate. Minimal refresh rate defined by VESA is 60Hz (60fps). This is why most modern monitors don't accept lower horizontal refresh rate than 31.5kHz. With vertical refresh rate it is a bit better, because introduction of HDMI compatibility, with its TV standards, forced 50Hz, so the majority of monitors that have a HDMI port should accept 50Hz.

== Problems with old computers ==

As you can see when one wants to connect an old computer to a modern display, one can encounter problems like:

* color decoding in PAL/NTSC signal (in case of Composite Video or S-Video signal),
* finding exact pixel clock frequency,
* double horizontal refresh rate (when we double 15.5kHz we are close enough to be accepted by modern displays),
* some modern displays don't have analog input - only digital.

== Solution ==

* The first problem to solve is decoding PAL or NTSC signal (some old computers don't have RGB output). To achieve that Medusa uses specialised video decoder, an integrated circuit created by Analog Devices, that can sample and decode SDTV signal (PAL, NTSC or even SECAM).

* The second problem is to find the exact pixel clock for the input signal (for RGB signals). There are no ultimate solution for this. In Medusa you can always manually define number of pixels per line, but to achieve that more automatically we measure a specific signal "fingerprint" (based on synchro signals) and pick one from dozens of available pre-set options.

* The third problem is to double the horizontal refresh rate. To achieve that every line from input is put into a small memory block inside an FPGA chip and then emitted twice. This is why sometimes we call such devices "scan doublers". This is of course done only when necessary (input horizontal refresh rate is lower than 31kHz).

* The last problem is to output a signal in digital form. In Medusa we decided to use DVI-I standard. DVI standard is theoretically obsoleted by HDMI, but since HDMI is licensed and DVI not, we decided to use DVI. Also DVI in full version (which is implemented in Medusa) also outputs all signals in analog format. This is very convenient because it allows the use of older 17" and 19" LCD panels, that are very cheap and have better screen proportions for old computers than new TV's. At the same time, using a simple cable, one can also connect it to an HDMI device.

== Why Medusa? ==

This is actually a very good question. There are a lot of devices that do similar things. The only problem is ... I've tried almost all of them (FrameMeister included). They all lacked something.

* Cheap Chinese devices use chips designed for TV's, with a lot of features that are good in case of movies but unacceptable in case of computers (few frames of latency). Also picture quality is horrible - RGB signal is sampled with constant ratio - not in sync with original pixels. They can't accept anything other than PAL or NTSC-like signals (forget about ST-mono or Amiga-AGA funny resolutions).

* FrameMeister - a very good device, but expensive. It also accepts only PAL and NTSC-like resolution (no ST-mono etc.).

* OSSC - also a very good device, but without composite video and s-video inputs. Only good for RGB signals. Tough to configure.

So what can Medusa do?

* Accept CVBS signal (Composite Video) on SCART (or JP21 - special JP21 version)
* Accept S-Video signal on SCART (or JP21)
* Accept RGB signal on SCART or VGA input (with more than 50 predefined settings for popular old computers; it can work not only with ST-mono, but also Viking card emulated by MIST - yes 1280x1024 !!!; more modes will be added with future firmware updates)
* Encode audio on DVI; this option can be switched on and (using DVI-HDMI adapter and HDMI capable display) audio signal from SCART (or 3.5mm jack) is digitised and mixed with video
* Allows user to change a lot of settings on the fly using OSD or built-in OLED display (settings such as contrast, brightness, X/Y picture shift etc.).
* Output signal analog and digital at the same time on DVI-I, so it can be connected both to old VGA monitors (also CRT ones) as well as modern HDMI monitors or TV's.
* Easy firmware update (no special device is needed - just connect Medusa via USB to a computer and run binary updater - available for Win,Linux,MacOS)

Why Medusa is not perfect? :)

Because a perfect solution does not exist. Medusa doesn't change vertical refresh rate, so if your monitor can't accept 50Hz then it will not display video from Medusa. Most monitors with HDMI inputs are able to display 50Hz (because of TV standards), but that's not not always the case with old VGA LCD panels. I have good experiences with LG's and NEC's, but can't guarantee that a particular monitor will accept 50Hz. Probably at some point we will prepare a list of monitors that can do that. With such approach to screen conversion (simple line doubling) any resolution change on input will also lead to resolution change on output. Even small change will usually cause a black screen on the displaying device (for about 0.5 - 1 second). This is normal - this is how displaying devices work. The only way to circumvent that would be to constantly display a picture in a chosen resolution (for example 1920x1080@60) and sample pixels from input and put them in a displayed framebuffer. But in this approach a lot of problems would occur. For example all 50Hz scrolls would be jagged. This is why we decided not to do that. Also the device would be much more expensive.

== Internals of Medusa ==

[[File:Medusa_internals.png|851px|frameless|block diagram of Medusa]]

File:Medusa internals.png

2022-07-11T12:43:34Z

Acid: Acid uploaded a new version of File:Medusa internals.png

Description

2022-07-11T12:43:07Z

Acid:

File:Medusa internals.png

2022-07-11T12:35:06Z

Acid:

Firmware Update

2022-07-07T11:17:39Z

Acid: /* Firmware Update */

Firmware Update

2022-07-07T11:16:34Z

Acid: /* Firmware Update */

== Firmware Update ==

# Download firmware from [http://medusa-sc.org/firmware/ Medusa Firmwares Page]. Firmware updater is a binary application that will update the firmware automatically. Binaries are available for Linux (64bit binary for Intel), Max OS X (Intel and ARM binaries) and Windows (32bit and 64bit binaries for Intel).
# Make sure that Medusa has been correctly detected by your operating system. Medusa uses standard "virtual serial port" (CDC) protocol on USB, so usually it should work without any drivers on Linux and Macos. In case of Windows the needed driver is usually installed, but if it is not, then install it. Description is [https://docs.microsoft.com/en-us/windows-hardware/drivers/usbcon/usb-driver-installation-based-on-compatible-ids here]
# Run the application. On the console you should see something like this (typically it takes less than 10 seconds):
<pre>
$ ./firmware_updater_macosx_arm
firmware leng: 170328B
Found port: /dev/cu.usbmodemF2ECEB871
port: /dev/cu.usbmodemF2ECEB871 - main app
Sending fwupdater data
......................................
Sending fwupdater hmac
Found port: /dev/cu.usbmodemF2ECEB871
port: /dev/cu.usbmodemF2ECEB871 - updater
Sending main code data
...................................................................................................................................
Sending main code hmac
Sending fpga core data
........................................................................................................................................................................
Sending fpga core hmac
</pre>

== To brick or not to brick ==

Firmware in Medusa is divided into two parts - simple updater (let's call it part A) and the main program (call it part B).

Part A updates part B (plus FPGA core) and part B updates part A

Boot code in Medusa checks checksums for both parts. If both checksums are correct then it jumps to part B (or part A when "right" button is pressed). If only one of them is correct then it jumps to this part directly. This design prevents device "bricking". Even you loose power during Medusa firmware update, after you turn it back on it will just use the valid part of the firmware. You will only need to run the updater again to complete the procedure.

Firmware Update

2022-07-07T11:11:23Z

Acid: Created page with "== Firmware Update == # Download firmware from [http://medusasc.org/machina Medusa Firmwares Page]. Firmware updater is a binary application that will update the firmware automatically. Binaries are available for Linux (64bit binary for Intel), Max OS X (Intel and ARM binaries) and Windows (32bit and 64bit binaries for Intel). # Make sure that Medusa has been correctly detected by your operating system. Medusa uses standard "virtual serial port" (CDC) protocol on USB, s..."

== Firmware Update ==

# Download firmware from [http://medusasc.org/machina Medusa Firmwares Page]. Firmware updater is a binary application that will update the firmware automatically. Binaries are available for Linux (64bit binary for Intel), Max OS X (Intel and ARM binaries) and Windows (32bit and 64bit binaries for Intel).
# Make sure that Medusa has been correctly detected by your operating system. Medusa uses standard "virtual serial port" (CDC) protocol on USB, so usually it should work without any drivers on Linux and Macos. In case of Windows the needed driver is usually installed, but if it is not, then install it. Description is [https://docs.microsoft.com/en-us/windows-hardware/drivers/usbcon/usb-driver-installation-based-on-compatible-ids here]
# Run the application. On the console you should see something like this (typically it takes less than 10 seconds):
<pre>
$ ./firmware_updater_macosx_arm
firmware leng: 170328B
Found port: /dev/cu.usbmodemF2ECEB871
port: /dev/cu.usbmodemF2ECEB871 - main app
Sending fwupdater data
......................................
Sending fwupdater hmac
Found port: /dev/cu.usbmodemF2ECEB871
port: /dev/cu.usbmodemF2ECEB871 - updater
Sending main code data
...................................................................................................................................
Sending main code hmac
Sending fpga core data
........................................................................................................................................................................
Sending fpga core hmac
</pre>

== To brick or not to brick ==

Firmware in Medusa is divided into two parts - simple updater (let's call it part A) and the main program (call it part B).

Part A updates part B (plus FPGA core) and part B updates part A

Boot code in Medusa checks checksums for both parts. If both checksums are correct then it jumps to part B (or part A when "right" button is pressed). If only one of them is correct then it jumps to this part directly. This design prevents device "bricking". Even you loose power during Medusa firmware update, after you turn it back on it will just use the valid part of the firmware. You will only need to run the updater again to complete the procedure.

Main Page

2022-07-07T10:33:38Z

Acid:

Welcome to Medusa Wiki

[[Description]]

[[Using Medusa]]

[[Menu]]

[[Troubleshooting]]

[[Console]]

[[Recognised Modes]]

[[Sample phase / Pixers per line]]

[[Firmware Update]]

[[Credits]]

Troubleshooting

2022-06-28T14:43:37Z

Acid: /* Troubleshooting */

== Troubleshooting ==

* '''Medusa logo turns on and off and nothing happens'''

Check power. Medusa has overvoltage and undervoltage protection circuit and it cuts off the power when voltage drops below about 4.5V. To work, Medusa needs substantial amount of current (more than 400mA). When you connect it for example to a computer using a passive HUB then voltage can easily drop down even to 4.2V. Nevertheless just after start all A/D converters are powered off and FPGA chip has no core loaded. In this state it needs less power and therefore voltage doesn't drop that bad. In such case it may be able to send the logo to the display and then when all circuits are powered, voltage drops and causes device reset.

* '''No Picture'''

[[File:no_signal.png|400px|thumb]]

When you connect Medusa to your displaying device even without any signal on input you should see control picture (on the right)

# Check if your DVI window is set to default (DVI: 720x576) - if not then reset current settings (reset -> rst curr prof) or manually change window to 720x576 (shift/size -> dvi presets -> 720x576). You may also experiment with 720x480 and 640x480, but 720x576 is the most compatible window size for 50Hz.
# Check if Medusa is switched to "pure DVI" mode (global options -> DVI mode -> pure DVI). Some (especially DVI) devices do not accept audio packets and do not display anything when audio packets are present in DVI stream. Especially good old 17" and 19" VGA monitors are not compatible with audio.
# If after that your device still does not display anything it may mean either cable problems or that your device is not compatible with signal produced by Medusa. Control screen is generated with vertical frequency of 50Hz. Since almost all old computers also generate picture with refresh rate of 50Hz then it means that your device has to be capable of displaying 50Hz. If it is not, then you may need to find another device.
# Check input cables or try different input signal

* '''SDTV picture is ugly'''

# Try to avoid connecting signal using composite video - always use s-video cables if possible
# To reduce stripes/noise you may consider using smoothing (filter -> smoothing -> 5-10)
# If you only want monochromatic picture and you have s-video cable you may consider "hacking" Medusa and forcing it to process only luminance signal using RGB A/D. Enter these commands in USB/serial console:
<pre>
cmd :>scartmode rgb
cmd :>setyasg 1
cmd :>rgbcurve mfg 1
cmd :>rgbcomponent 1
</pre>

* '''RGB picture is ugly'''

# If your device hasn't been detected (you see "unknown PAL", "unknown NTSC", "unrecognised lo" or "unrecognised hi" on second line on OLED/OSD - also if you see a name that does not match your device) then you should manually adjust pixels per line parameter (rgb only -> pixels/line) - see [[Sample phase / Pixers per line]]. In such case consider contacting us with the device's fingerprint (rgb only -> fingerprint). We might be able to add your device to the list of recognised devices in future firmwares.
# If your device has been properly detected but the picture is not crystal clear - first try to adjust sample phase (rgb only -> sample phase) - see [[Sample phase / Pixers per line]].
# If you see a lot of noise you may try to increase smoothing (filter -> smoothing -> 5-10), but also check power cables (yes power cables). Source of picture noise is usually on the ground signal. To reduce ground noise you may consider connecting ground of Medusa with ground of your device using separate cable. Although it is counterintuitive, exchange your modern filtered multiple outlet extension cord for a basic one (without filters, switches etc). Very often such noise is generated by power supply - try different power supply unit.

* '''Displaying device looses sync whenever input resolution changes'''

:: It is normal. Medusa processes picture line by line. In such case whenever input line is missing (i.e. during input mode switch) also lines are missing on the output. Practically all displaying devices loose sync (even multisync CRT displays). Usually it means that the display becomes blank for half a second or so. See the [[Description]] chapter.

Troubleshooting

2022-06-28T10:41:49Z

Acid: /* Troubleshooting */

== Troubleshooting ==

* '''Medusa logo turns on and off and nothing happens'''

Check power. Medusa has overvoltage and undervoltage protection circuit and it cuts off the power when voltage drops below about 4.5V. To work Medusa needs substantial amount of current (more than 400mA). When you connect it for example to a computer using passive HUB then voltage can easily drop down even to 4.2V. Nevertheless just after start all A/D converters are powered off and FPGA chip has no core loaded. In this state it needs less power and therefore voltage doesn't drop that bad. In such case it may be able to send the logo to the display and then when all circuits are powered, voltage drops and causes device reset.

* '''No Picture'''

[[File:no_signal.png|400px|thumb]]

When you connect Medusa to your displaying device even without any signal on input you should see control picture (on the right)

# Check if your DVI window is set to default (DVI: 720x576) - if not then reset current settings (reset -> rst curr prof) or manually change window to 720x576 (shift/size -> dvi presets -> 720x576). You may also experiment with 720x480 and 640x480, but 720x576 is the most compatible window size for 50Hz.
# Check if Medusa is switched to "pure DVI" mode (global options -> DVI mode -> pure DVI). Some (especially DVI) devices do not accept audio packets and do not display anything when audio packets are present in DVI stream. Especially good old 17" and 19" VGA monitors are not compatible with audio.
# If after that your device still does not display anything it may mean either cable problems or that your device is not compatible with signal produced by Medusa. Control screen is generated with vertical frequency of 50Hz. Since almost all old computers also generate picture with refresh rate of 50Hz then it means that your device has to be capable of displaying 50Hz. If it is not, then you may need to find another device.
# Check input cables or try different input signal

* '''SDTV picture is ugly'''

# Try to avoid connecting signal using composite video - always use s-video cables if possible
# To reduce stripes/noise you may consider using smoothing (filter -> smoothing -> 5-10)
# If you only want monochromatic picture and you have s-video cable you may consider "hacking" Medusa and forcing it to process only luminance signal using RGB A/D. Enter these commands in USB/serial console:
<pre>
cmd :>scartmode rgb
cmd :>setyasg 1
cmd :>rgbcurve mfg 1
cmd :>rgbcomponent 1
</pre>

* '''RGB picture is ugly'''

# If your device hasn't been detected (you see "unknown PAL", "unknown NTSC", "unrecognised lo" or "unrecognised hi" on second line on OLED/OSD - also if you see a name that does not match your device) then you should manually adjust pixels per line parameter (rgb only -> pixels/line) - see [[Sample phase / Pixers per line]]. In such case consider contacting us with the device's fingerprint (rgb only -> fingerprint). We might be able to add your device to the list of recognised devices in future firmwares.
# If your device has been properly detected but the picture is not crystal clear - first try to adjust sample phase (rgb only -> sample phase) - see [[Sample phase / Pixers per line]].
# If you see a lot of noise you may try to increase smoothing (filter -> smoothing -> 5-10), but also check power cables (yes power cables). Source of picture noise is usually on the ground signal. To reduce ground noise you may consider connecting ground of Medusa with ground of your device using separate cable. Although it is counterintuitive, exchange your modern filtered multiple outlet extension cord for a basic one (without filters, switches etc). Very often such noise is generated by power supply - try different power supply unit.

* '''Displaying device looses sync whenever input resolution changes'''

:: It is normal. Medusa processes picture line by line. In such case whenever input line is missing (i.e. during input mode switch) also lines are missing on the output. Practically all displaying devices loose sync (even multisync CRT displays). Usually it means that the display becomes blank for half a second or so. See the [[Description]] chapter.

Troubleshooting

2022-06-24T11:32:18Z

Acid: /* Troubleshooting */

== Troubleshooting ==

* No Picture

[[File:no_signal.png|400px|thumb]]

When you connect Medusa to your displaying device even without any signal on input you should see control picture (on the right)

# Check if your DVI window is set to default (DVI: 720x576) - if not then reset current settings (reset -> rst curr prof) or manually change window to 720x576 (shift/size -> dvi presets -> 720x576). You may also experiment with 720x480 and 640x480, but 720x576 is the most compatible window size for 50Hz.
# Check if Medusa is switched to "pure DVI" mode (global options -> DVI mode -> pure DVI). Some (especially DVI) devices do not accept audio packets and do not display anything when audio packets are present in DVI stream. Especially good old 17" and 19" VGA monitors are not compatible with audio.
# If after that your device still does not display anything it may mean either cable problems or that your device is not compatible with signal produced by Medusa. Control screen is generated with vertical frequency of 50Hz. Since almost all old computers also generate picture with refresh rate of 50Hz then it means that your device has to be capable of displaying 50Hz. If it is not, then you may need to find another device.
# Check input cables or try different input signal

* SDTV picture is ugly

# Try to avoid connecting signal using composite video - always use s-video cables if possible
# To reduce stripes/noise you may consider using smoothing (filter -> smoothing -> 5-10)
# If you only want monochromatic picture and you have s-video cable you may consider "hacking" Medusa and forcing it to process only luminance signal using RGB A/D. Enter these commands in USB/serial console:
<pre>
cmd :>scartmode rgb
cmd :>setyasg 1
cmd :>rgbcurve mfg 1
cmd :>rgbcomponent 1
</pre>

* RGB picture is ugly

# If your device hasn't been detected (you see "unknown PAL", "unknown NTSC", "unrecognised lo" or "unrecognised hi" on second line on OLED/OSD - also if you see a name that does not match your device) then you should manually adjust pixels per line parameter (rgb only -> pixels/line) - see [[Sample phase / Pixers per line]]. In such case consider contacting us with the device's fingerprint (rgb only -> fingerprint). We might be able to add your device to the list of recognised devices in future firmwares.
# If your device has been properly detected but the picture is not crystal clear - first try to adjust sample phase (rgb only -> sample phase) - see [[Sample phase / Pixers per line]].
# If you see a lot of noise you may try to increase smoothing (filter -> smoothing -> 5-10), but also check power cables (yes power cables). Source of picture noise is usually on the ground signal. To reduce ground noise you may consider connecting ground of Medusa with ground of your device using separate cable. Although it is counterintuitive, exchange your modern filtered multiple outlet extension cord for a basic one (without filters, switches etc). Very often such noise is generated by power supply - try different power supply unit.

* Displaying device looses sync whenever input resolution changes

:: It is normal. Medusa processes picture line by line. In such case whenever input line is missing (i.e. during input mode switch) also lines are missing on the output. Practically all displaying devices loose sync (even multisync CRT displays). Usually it means that the display becomes blank for half a second or so. See the [[Description]] chapter.

Sample phase / Pixers per line

2022-06-24T11:30:08Z

Acid: /* Sample phase */

== Sample phase ==

Example of sample phase set wrongly (click to zoom):

[[File:phase_bad.png|400px|frameless|bad sample phase]]

Example of sample phase set correctly (click to zoom):

[[File:phase_good.png|400px|frameless|good sample phase]]

== Pixels per line ==

All recognised RGB modes should have this option set correctly in the firmware, but when your device is not recognised ("unknown PAL", "unknown NTSC", "unrecognised lo" or "unrecognised hi") then you should set correctly pixels per line. If you want me to add your device to the next Medusa firmware I will need this parameter together with fingerprint. I've prepared a couple of pictures to help setting this parameter correctly.

First try to fill your screen with "50%" checkboard pattern (desktop background setting or using any raster graphics program like Deluxe Paint)

Example of pixels per line set too low (click to zoom):

[[File:ppl_toolow.png|400px|frameless|bad sample phase]]

Example of pixels per line set too high (click to zoom):

[[File:ppl_toohigh.png|400px|frameless|bad sample phase]]

As you can see in both cases there are vertical artifacts, but one can't say if it is too low or too high. Both cases looks similar. One way is to check hardware of your device and try to find master clock generator (in this case it is Atari ST with main clock of 32.084MHz). Your pixel clock (Pfreq) should be set to the same value (or its multiple). The other way is to increase or decrease this setting (using "dec by 16" and "inc by 16" at the beginning) and try to be as close as possible (as low vertical lines with artifacts as possible).

At some point you will have only a few artifacts. This is an example of a picture with one artifact only:

[[File:ppl_close.png|400px|frameless|bad sample phase]]

When you have achieved that, then try to change this value using only "dec by 1" and "inc by 1" - usually only even values will be correct. When the value is correct your picture should look like this:

[[File:ppl_good.png|400px|frameless|bad sample phase]]

Sample phase / Pixers per line

2022-06-24T11:29:37Z

Acid: Created page with "== Sample phase == Example of sample phase set wrongly (clock to zoom): bad sample phase Example of sample phase set correctly (clock to zoom): good sample phase == Pixels per line == All recognised RGB modes should have this option set correctly in the firmware, but when your device is not recognised ("unknown PAL", "unknown NTSC", "unrecognised lo" or "unrecognised hi") then you should..."

== Sample phase ==

Example of sample phase set wrongly (clock to zoom):

[[File:phase_bad.png|400px|frameless|bad sample phase]]

Example of sample phase set correctly (clock to zoom):

[[File:phase_good.png|400px|frameless|good sample phase]]

== Pixels per line ==

All recognised RGB modes should have this option set correctly in the firmware, but when your device is not recognised ("unknown PAL", "unknown NTSC", "unrecognised lo" or "unrecognised hi") then you should set correctly pixels per line. If you want me to add your device to the next Medusa firmware I will need this parameter together with fingerprint. I've prepared a couple of pictures to help setting this parameter correctly.

First try to fill your screen with "50%" checkboard pattern (desktop background setting or using any raster graphics program like Deluxe Paint)

Example of pixels per line set too low (click to zoom):

[[File:ppl_toolow.png|400px|frameless|bad sample phase]]

Example of pixels per line set too high (click to zoom):

[[File:ppl_toohigh.png|400px|frameless|bad sample phase]]

As you can see in both cases there are vertical artifacts, but one can't say if it is too low or too high. Both cases looks similar. One way is to check hardware of your device and try to find master clock generator (in this case it is Atari ST with main clock of 32.084MHz). Your pixel clock (Pfreq) should be set to the same value (or its multiple). The other way is to increase or decrease this setting (using "dec by 16" and "inc by 16" at the beginning) and try to be as close as possible (as low vertical lines with artifacts as possible).

At some point you will have only a few artifacts. This is an example of a picture with one artifact only:

[[File:ppl_close.png|400px|frameless|bad sample phase]]

When you have achieved that, then try to change this value using only "dec by 1" and "inc by 1" - usually only even values will be correct. When the value is correct your picture should look like this:

[[File:ppl_good.png|400px|frameless|bad sample phase]]

Main Page

2022-06-24T11:04:30Z

Acid:

Welcome to Medusa Wiki

[[Description]]

[[Using Medusa]]

[[Menu]]

[[Troubleshooting]]

[[Console]]

[[Recognised Modes]]

[[Sample phase / Pixers per line]]

[[Credits]]

File:Phase good.png

2022-06-24T11:02:50Z

Acid:

File:Phase bad.png

2022-06-24T11:02:08Z

Acid:

File:Ppl toolow.png

2022-06-24T11:01:33Z

Acid:

File:Ppl toohigh.png

2022-06-24T11:01:05Z

Acid: Acid uploaded a new version of File:Ppl toohigh.png

File:Ppl toohigh.png

2022-06-24T11:00:35Z

Acid:

File:Ppl close.png

2022-06-24T10:59:21Z

Acid:

File:Ppl good.png

2022-06-24T10:58:45Z

Acid:

Troubleshooting

2022-06-22T18:33:05Z

Acid:

== Troubleshooting ==

* No Picture

[[File:no_signal.png|400px|thumb]]

When you connect Medusa to your displaying device even without any signal on input you should see control picture (on the right)

# Check if your DVI window is set to default (DVI: 720x576) - if not then reset current settings (reset -> rst curr prof) or manually change window to 720x576 (shift/size -> dvi presets -> 720x576). You may also experiment with 720x480 and 640x480, but 720x576 is the most compatible window size for 50Hz.
# Check if Medusa is switched to "pure DVI" mode (global options -> DVI mode -> pure DVI). Some (especially DVI) devices do not accept audio packets and do not display anything when audio packets are present in DVI stream. Especially good old 17" and 19" VGA monitors are not compatible with audio.
# If after that your device still does not display anything it may mean either cable problems or that your device is not compatible with signal produced by Medusa. Control screen is generated with vertical frequency of 50Hz. Since almost all old computers also generate picture with refresh rate of 50Hz then it means that your device has to be capable of displaying 50Hz. If it is not, then you may need to find another device.
# Check input cables or try different input signal

* SDTV picture is ugly

# Try to avoid connecting signal using composite video - always use s-video cables if possible
# To reduce stripes/noise you may consider using smoothing (filter -> smoothing -> 5-10)
# If you only want monochromatic picture and you have s-video cable you may consider "hacking" Medusa and forcing it to process only luminance signal using RGB A/D. Enter these commands in USB/serial console:
<pre>
cmd :>scartmode rgb
cmd :>setyasg 1
cmd :>rgbcurve mfg 1
cmd :>rgbcomponent 1
</pre>

* RGB picture is ugly

# If your device hasn't been detected (you see "unknown PAL", "unknown NTSC", "unrecognised lo" or "unrecognised hi" on second line on OLED/OSD - also if you see a name that does not match your device) then you should manually adjust pixels per line parameter (rgb only -> pixels/line). In such case consider contacting us with the device's fingerprint (rgb only -> fingerprint). We might be able to add your device to the list of recognised devices in future firmwares.
# If your device has been properly detected but the picture is not crystal clear - first try to adjust sample phase (rgb only -> sample phase).
# If you see a lot of noise you may try to increase smoothing (filter -> smoothing -> 5-10), but also check power cables (yes power cables). Source of picture noise is usually on the ground signal. To reduce ground noise you may consider connecting ground of Medusa with ground of your device using separate cable. Although it is counterintuitive, exchange your modern filtered multiple outlet extension cord for a basic one (without filters, switches etc). Very often such noise is generated by power supply - try different power supply unit.

* Displaying device looses sync whenever input resolution changes

:: It is normal. Medusa processes picture line by line. In such case whenever input line is missing (i.e. during input mode switch) also lines are missing on the output. Practically all displaying devices loose sync (even multisync CRT displays). Usually it means that the display becomes blank for half a second or so. See the [[Description]] chapter.