Hello,
I juste finished building my A2 VGA card from Ralle Palaveev github version 1.4.
The board seems to work (I get a VGA output) but always in cyrillic and the utility disk doesn't recognize it !
Did someone had the same issues ?
Thank you in advance for your help !
How did you load the firmware onto the Pico? I'd try that again and make sure that you have the right version if you don't want Cyrillic.
Did you build it using the PLD (22V10)? If not is your card properly jumpered for that to be off? I haven't built any cards w/o the PLD so I don't know if it is required for the utility to work.
I load the firmware in two steps, first the preloader, then the v2-analog-wifi-4ns-vga.uf2 from the V2-Analog-RGB9-20230504 version, in one session.
First I tryed with the PLD, but I took it off to narrow the issue diagnostic (and I closed the NoPLD jumper).
When I load the utility disk, the only option is "Exit" :(
But I try some games and softwares and all display fine (exept from the Cyrillic of course) ...
Getting VGA out is the 'easy bit' for these cards. It only shows you have the output and the power to the Pico right. You need to go and cross check every single trace from the slot to the level shifters, and back again 3 time, it is very very likely you missed one (at least).
The PLD is not required for the utilities to work. I do question what version of the utility he is using . I would recommend the config utility v1.3.0 and the v1.3.0 pico firmware.
Hello BusError,
I've checked all traces and everything looks OK.
But I've made further tests:
- It seems that the card doen't works properly if the 220V10C is missing (even with the jumper NoPLD closed).
- It also seems that some SLOTS are better than others, 3 and 7 are not working (OK for 3, but 7 !?!).
- The Utility disk crash to the monitor but the modified version from MacFly (https://www.applefritter.com/comment/106213#comment-106213) starts. Then I can save some configs (no more Cyrillics). I can change/save Machine Type / Fonts / Wifi ... But not the colors !!!
I begin to think that my build is correct but there's some imcompatibilties between firmware / utilities / version 1.4
The only problem I've had with A2VGA cards not working right was bad 74LVC245 chips. With the bad chips they would ALMOST work, but did weird things. Maybe try different chips if you have any. I ended up having to order from a different vendor (Juried Engineering) to get good chips.
I always use his firmware and config as a set and most of the problems go away. I have noticed that when I have the card is slot 4 it gets detected as slot 3 (I correct it and it works) but in slot 5, it detects properly. I suspect this is due to the resistance values being too high and not well formed square waves as MacFly posted earilier in that thread but I don't have a scope to test. I built a few of these 1.4 versions. With my earlier builds I didn't have all the correct values of resistors so I added some to get close. My latest one, I did get the right values, except for 2.5k (was unable to source that one). But with the better sourced parts, my build behaved no better or worse. I also turned one into a CP/M and converted one to a mouse board. Both of those worked.
Hi DBrownlee,
No I did'nt found those precious firmwares ! If you have some links ...
And I had the same sourcing issue with 2.5K, so I use a 2K+500 ... seems to work.
I have the 22V10C in place but I have'nt tryed the CP/M yet ... One problem at a time :)
I've found the "scanline" version of the firmware, but only for LC Pico ... I've installed it (even if I have the Wifi version) and it works, now I have scanlines, but still no background/border colors ...
I also have the WiFi version but I don't think anyone has developed it out. All development seemed to go to a2pico. For the setting of colors, are you setting monochrome mode to custom? That is the only way I can set bg colors. Normally I am running disabled or amber.
Ok, my mistake !
For color change to be effective, you must first select an appropriate monochrome mode !!!
This menu option is a bit misleading, at least for me ... And most of all, I even not tryed to give it a try :(
So mystery solved, my card is working fine, in VGA mode ... Now I will try the CP/M version ...
Thank you DBrownlee for all your advices ...
In hardware revision 1.4, I have had good success by actually changing the voltage dividers to a series 1K resistor (like some of the other similar designs). I know this really isn't the best design, but I do get reasonably good looking waveforms and operation. Short of using actual level converters, this has provided me the best success.
What I did was: Remove R15, R16, R18 and Change R19 to 1K. I never bothered replacing R18 as having /reset control run on the RP2040 is really unnecessary.
Works in every slot. Works with C/PM. Works as a mouse with added components to support /IRQ. Works with Mark Akins current firmware version 1.3.0 and the utilities.
Wow, cool, I have 4 more PCB unpopulated ... I will give it a try and tell you ...
Many thanks...
Thanks, chrisa850! It does indeed solve the incorrect slot identification I was having with the 1.4 version of the card. Although this was more of an annoyance than a real issue for me, it is good to have it behaving normally. Thanks again!