I have written a little blog article on a new project, a collaboration between Ralle Palaveev and me. For those interested in the details, see here:
https://www.applefritter.com/content/a2dvi-apple-ii-digital-video-card
The short summary is: a new PICO based Apple II graphics card - just like the propular analog VGA cards - but with an alternative HDMI connector. So a card with digital video output instead of analog VGA.
It's just as simple and cheap as the original analog VGA design. And it works really well! :)
Creating this forum topic for related discussions. We're currently testing. The firmware is almost complete. Gerber files aren't published just yet, but Ralle has some PCBs for testing. If someone wants to help with testing, let us know. Otherwise be a little patient... :)
Nice!
I see you already have provisions for multiple fonts. Let me know if you're interested in supporting the font selecion protocol used by ROMX boards. Would love to see at least one more board out there that does that.
I saw the code for ROMX support in the analog VGA source base I used. It's still there but currently disabled for the A2DVI. My font selection support slightly differs from the original, due to the new "language switch" support. And I didn't fully understand what the "ROMX textbanks" were exactly meant to be doing. :D But it's certainly something that can be supported again. It's one of the topics where we could do with some help for testing...
Basically, ROMX supports a replacement Video ROM that offers up to 32 different fonts. And selection is made through the ROMX menu or programmatically using our API. If you wanted to use your existing bus sniffing to detect when a font is selected you could then activate a similar font for the DVI output. I'd be happy to help out with this as well as general testing in various machines. DM me and we can work out the details.
Amazing work, guys! Are you sure you are not using a bootstrap paradox?
Hi
I'd love to help you guys test this across multiple plato forms and configurations. Please let me know how and if I can help!!
Michael Schaffer
Thanks, yeah, not sure: I told Ralle several times, it couldn't work. But that was before finding the RP2040's two powerful slave FCUs (Flux Capacitor Units)... ;-)
@jeff, @michael: PM.
Thats great work, thanks you guys for doing this.
I'm a little hopeful with you involved Macfly, that once this is finished off, then we might see some attempt to get a A/// version working.
Hahaha, the idea has crossed my mind. :) But with the A/// it always feels there's only three people interested in related projects (me included..). But, who knows...
Here's something I have added to the A2DVI firmware: optional debug/status lines - as an option in the configuration menu. It shows the status of all Apple II soft switches at the top (in the free space above the Apple II screen), and some extra data below: currently the execution program counter, the stack pointer and address of the most recent zero-page access. It's not an exact science, since you can't see every single address, of course. Originally this was meant to help debugging the A2DVI itself.
But I find it still interesting and useful even for A2DVI unrelated cases, e.g. when your machine doesn't boot or your program was stuck, and you wonder what the heck the 6502 was doing right now. It's also interesting to see what a running program is doing - for example, executing code from a a specific slot ROM, the main ROM - or when a program enables the AUX MEM soft-switches, in order to access the extended memory banks of the IIe.
Here's an example: shows the soft-switches are configured to "HGR" (hires graphics), "40 column mode" and "page 1". All other soft-switches are off. And below: current execution PC at $AF42, stack recently accessed at $1F8, zero-page accessed at $2E...
A2DVI_DebugStatus.jpg
That's not spcific to the HDMI output, of course, could be done for analog VGA in the same way. Just shows the PICOs direct 6502 bus connection is also useful for other stuff. A card like this could be turned into a little debug/tracing utility. It has access to every single memory cycle, every single address, every single data byte. Opens up possibilities, almost like in an emulator...
I guess I'm the third one then :) I'd build it to get better color video out of my A///.
Hi,
this is awesome, also the support for another character set (I am from Austria and often use German character sets).
I want to ask if this also supports Apple IIGS or if rgb2HDMI is still the better solution for IIGS.
best regards
clockchip
This card doesn't support the Apple IIgs. (At least at this point in time, but those of us who are not involved with the project could be up for yet one more amazing surprise from Thorsten and Ralle!)
For the IIgs I would argue that the best equivalent solution is the A2FPGA card: https://wiki.reactivemicro.com/A2FPGA
Yes, IIgs support is currently not implemented. The code base from the VGA project I used did have IIgs support. But the IIgs requires additional video modes, and each mode needs to be ported for DVI separately. The IIgs modes are also a bit more tricky, due to higher resolutions, more colors and configurable palettes. Might be possible. But I don't think I'll be working on those any time soon.
Also, Raspberry announced a successor to the PICO yesterday. PICO2 has even better CPU cores and better I/O. And PICO2 is pin-compatible to the current boards. That may also allow more additions in the future...
Hi,
I am a low-income senior and would love to test the new A2DVI boards in my Apple II Plus computer.
I like playing around with basic graphics and basic math functions to sketch stuff on the screen.
e.g.,
10 GR : HCOLOR = 3
20 REM CALCULATE CENTER
30 CX = 140 : CY = 96
40 REM SET UP OCTAGON SIDES
50 FOR I = 0 TO 7
60 X1 = CX + 50 * COS((I * 45) * 3.14159 / 180)
70 Y1 = CY + 50 * SIN((I * 45) * 3.14159 / 180)
80 X2 = CX + 50 * COS(((I + 1) * 45) * 3.14159 / 180)
90 Y2 = CY + 50 * SIN(((I + 1) * 45) * 3.14159 / 180)
100 HPLOT X1, Y1 TO X2, Y2
110 NEXT I
120 END