diff --git a/Images/Better.png b/Images/Better.png new file mode 100644 index 0000000..649cba6 Binary files /dev/null and b/Images/Better.png differ diff --git a/Images/Installed.png b/Images/Installed.png new file mode 100644 index 0000000..8b7edfe Binary files /dev/null and b/Images/Installed.png differ diff --git a/Images/Pink.png b/Images/Pink.png new file mode 100644 index 0000000..94c0d26 Binary files /dev/null and b/Images/Pink.png differ diff --git a/OSDSwitch/OSDSwitch.kicad_pcb b/OSDSwitch/OSDSwitch.kicad_pcb index e14ed9a..e54b009 100644 --- a/OSDSwitch/OSDSwitch.kicad_pcb +++ b/OSDSwitch/OSDSwitch.kicad_pcb @@ -78,7 +78,7 @@ (tenting front back) (pcbplotparams (layerselection 0x00000000_00000000_55555555_5755f5ff) - (plot_on_all_layers_selection 0x00000000_00000000_00000000_02000000) + (plot_on_all_layers_selection 0x00000000_00000000_00000000_00000000) (disableapertmacros no) (usegerberextensions no) (usegerberattributes yes) diff --git a/README.md b/README.md index d72471b..3863bca 100644 --- a/README.md +++ b/README.md @@ -3,3 +3,58 @@ FF-OSD Video Switcher for clean video output ![Video Interposer Board](OSDSwitch/OSDSwitch.png) +This is a small board with a high bandwidth video switching chip +on it. The idea is that this sits in between the video generation +circuitry and the video output socket of your Amiga (or similar +computer) and is controlled by the On Screen Display signal from +a modified Gotek (see [keirf/flashfloppy-osd](https://github.com/keirf/flashfloppy-osd). + +Normally the output of the OSD mod is just blasted unceremoniously +over the green (or channel of your choice) signal, overpowering the +circuitry in the receiving display system to give a green tint where +the text is. + +This is not great. It's crude, and doesn't always work right, and +the results are often less than desirable. + +This small board is the answer. It actively cuts out the normal +video signal when the OSD text should be displayed, and replaces that +video signal with a statically defined colour of your choice (configured +by 3 jumpers) to give a crystal clear OSD that is embedded within the +video stream, not overlayed on top of it. + +I developed this board because I use an Extron video scaler connected +to my Amiga for both video capture while livestreaming and for display +on a modern TFT screen. But the traditional overlay setup really didn't +work with the Extron. Everything went pink: + +![Pink Amiga](Images/Pink.png) + +And so this board was born. The ADG1633BCPZ looked to be the ideal +chip, with more than enough bandwidth for a video signal (one of the +intended applications for this chip), and three channels, the board +was pretty simple to design. And I think you'll agree the results +are much nicer: + +![Non-pink Amiga](Images/Better.png) + +(This image is from before I tweaked the resistor values a little, +so the OSD is a bit darker than I would have liked). + +Installation is reasonably simple. For the Amiga 500 (R6): + +* Lift the side of the three ferrite beads by the video connector that is facing + towards Denise (where you would normally solder the OSD wire to. +* Connect three wires to where they were soldered +* Attach the three wires to the INPUT side of the board's R G and B pins. +* Solder the ferrite beads you just lifted one side of to the output + R G and B pins +* Connect a 5V and GND signal from somewhere suitable +* Connect the signal from your OSD generator to the IN pin. + +Choose the colour you want with the jumpers (bonus hack: if you use resistors +instead of jumpers you can get a wider range of colours to choose from). + +And here it is installed in my Amiga: + +![Installed](Images/Installed.png)