I have some questions about the RGBtoHDMI project (hardware which adds HDMI video output to a range of vintage computers). I intend to add it to an STe:
1) According to the official Wiki project page for RGBtoHDMI 12-bit board, it is now at version 4. But several sellers have a version 7 (CJEmicros and RetroHackShack to mention a couple).
Is this an unoffical offshoot from the official one?
Is there a website with more information?
Are there file-downloads somewhere so I can make my own?
2) As I don't have much experience with SMD components and there's so much that can go wrong with this project (also involving multiple boards) I would like to buy it (and the other boards needed for it) ready-made.
I see that several PCB-manufacturing companies also offer ready made boards and not just bare boards, one of them being PCBway.
I suppose it's also possible to upload the Gerber and BOM files to other manufacturers.
Has anyone here ordered ready made RGBtoHDMI and 12-bit Extender boards? How did they come out and how much did they cost?
3) Since there's no buffer board available for the STe I'm working on a design for that, but I'm confused about the signal pins of the RGBtoHDMI and 12-bit extender boards. I've compared several of the existing buffer boards (Atari ST, Amiga, Atari ST with no buffer etc.) and I see that the signals aren't the same.
For instance, in one design (12-bit Atari ST buffered pickup board) the R3, G3 and B3 pins all receive the Atari ST MONO signal.
In other designs the SYNC pin receives a variety of sync type signals, and a modified Amiga buffer for use with the STe has CSYNC going to the SYNC pin of the RGBtoHDMI and MONO going to the VSYNC pin.
Is this because although the RGBtoHDMI input pins have a specific signal labelling they're not fixed, but the actual signal it will carry is determined by which profile has been chosen, differing between the various vintage computer settings?
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RGBtoHDMI for STe -some questions
RGBtoHDMI for STe -some questions
STe | MonSTer with dual IDE-CF memory card adapter | NEC Multisync 1990SXi | ST_ESSC | RSVE | Link '97 | Sony HD floppy drive/AJAX controller | Exxos HD floppy module | Battery-backed Ricoh realtime clock module | Discovery cartridge | C-Lab Unitor-2 | C-Lab Export | C-Lab Combiner | C-Lab Steady Eye | C-Lab Human Touch | Unicorn USB
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Re: RGBtoHDMI for STe -some questions
The answer to question 3 will be that ST only had a 9-bit colour and STe had 12-bit colour and so on the ST there is no R3, G3 or B3
Senior Principal ASIC Engineer - SystemVerilog, VHDL
Thalion Webshrine - http://thalion.atari.org
ST,STf,STfm,STe,MegaST,MegaSTe,Falcon060
A500+,A600,A4000/060,CD32,CDTV
Thalion Webshrine - http://thalion.atari.org
ST,STf,STfm,STe,MegaST,MegaSTe,Falcon060
A500+,A600,A4000/060,CD32,CDTV
Re: RGBtoHDMI for STe -some questions
Thanks for confirmingalexh wrote: Fri Sep 18, 2026 8:12 pm The answer to question 3 will be that ST only had a 9-bit colour and STe had 12-bit colour and so on the ST there is no R3, G3 or B3
Would it then be safe to also assume that the reason for the different signal names (on the input pins of the RGBtoHDMI) are indeed because they're not hardwired and fixed, but re-configurable. So the signal names don't necessarily match the actual signal received. Do you agree?
For instance, comparing the STe and ST, here showing only the pins that differ for simplicity (and with pin numbers of the RGBtoHDMI input connector in paranthesis):
| ST | STe | RGBtoHDMI input connector |
|---|---|---|
| MONO | R3 | R3 (11) |
| MONO | G3 | G3 (13) |
| MONO | B3 | B3 (15) |
| HSYNC | CSYNC | SYNC (12) |
| VSYNC | MONO | VSYNC (14) |
STe | MonSTer with dual IDE-CF memory card adapter | NEC Multisync 1990SXi | ST_ESSC | RSVE | Link '97 | Sony HD floppy drive/AJAX controller | Exxos HD floppy module | Battery-backed Ricoh realtime clock module | Discovery cartridge | C-Lab Unitor-2 | C-Lab Export | C-Lab Combiner | C-Lab Steady Eye | C-Lab Human Touch | Unicorn USB
Are you a good person?
Living Waters
Re: RGBtoHDMI for STe -some questions
These topics over on AF are probably helpful to you:
Flow diagrams which help understanding of how it works with ST & STe:
https://www.atari-forum.com/viewtopic.p ... 98#p487598
MegaSTe wiring:
https://www.atari-forum.com/viewtopic.p ... 08#p488108
STe wiring:
From page 4: https://www.atari-forum.com/viewtopic.p ... 21#p420221
Some slight differences in wiring, perhaps there was an error on page 4.
From page 5: https://www.atari-forum.com/viewtopic.p ... 17#p421117
Flow diagrams which help understanding of how it works with ST & STe:
https://www.atari-forum.com/viewtopic.p ... 98#p487598
MegaSTe wiring:
https://www.atari-forum.com/viewtopic.p ... 08#p488108
STe wiring:
From page 4: https://www.atari-forum.com/viewtopic.p ... 21#p420221
Some slight differences in wiring, perhaps there was an error on page 4.
From page 5: https://www.atari-forum.com/viewtopic.p ... 17#p421117
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Re: RGBtoHDMI for STe -some questions
I have 5 ready built rgb2hdmi hats if you want one, PM me. They are 12 bit issue 4s.
They have had basic tests done, they boot, displays the menu etc and the CPLD was programmable via RPi.
I haven't fully tested yet but I can if you want one.
They have had basic tests done, they boot, displays the menu etc and the CPLD was programmable via RPi.
I haven't fully tested yet but I can if you want one.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...

