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Built up a vdp board, the V1 version, got it programmed, and it displays on the HDMI attached monitor (still connected usb). The NABU I’m testing it in has an FDC & serial board (both known working), patched ROM V14, and runs off both Cycle 2 and locally off CP/M via the GoTek.

I put the new vdp in, and I’m greeted by the screen from it on the HDMI monitor, but it goes no further. I haven’t tried going back to a more “stock” configuration, but wondered if there are any known issues with it and maybe the FDC or patched ROM v14?

Shouldn’t the ROM boot menu screen just “appear”?

Update:

This is just weird. Took the NABU back to stock, no FDC, original ROM, TMS chip, works on cycle 2. Put in the tn_vdp and get inconsistent results. Sometimes it’ll show the vdp screen on the hdmi monitor, other times at power on it doesn’t, nor is the light on the nano on. Oddly at the same time the NABU itself gets either only the power led or none whatsoever. There must be something up with my build of the tn_vdp board.

Did you make any progress with this? I get very similar results. I've built two boards (used the same Tang Nano though) and neither work, twice I got a NABU screen, but it never progressed. Mostly I get the tv vdp splash screen, sometimes a corrupted screen.

I am flashing with openfpgaloader on a Mac as I don't have Windows machine, and I can't get the GOWIN software to run in a Windows virtual machine.

One difference from he Github instructions is that to update the fw, I have to add :
If anyone has any hints about debugging, I'd like to hear them. I have access to a well outfitted electronics lab.

I posted my findings at the end of the other big thread. Are you using HDMI or VGA out? HDMI support on the TN9K is poor at best. I had to hack the device to even display anything on screen. Also, forget running it under windows VM; I use the MacOS download of openFPGALoader or my custom build version on a Pi.

did you set the jumpers correctly ? you need cpuclk and gromclk for the nabu to work. (jumper 3 and 4 closed).

did you put the diode on the correct direction ? Are you disconnecting the usb-c before turning on ?

check the socket for any bent pins.

Hey, looks like there is some electrical issue with the V2 version of the board (flat cable). And it seems to manifest in different situations. I am looking at it to see how this can be fixed but it will take some time.

I am looking at it. The FAT and the Slim boards work fine.

I just submitted new version for V2 9918 and V2 9958. Try these.

Gidim wrote: ↑Tue Jul 04, 2023 11:24 pm Did you make any progress with this? I get very similar results. I've built two boards (used the same Tang Nano though) and neither work, twice I got a NABU screen, but it never progressed. Mostly I get the tv vdp splash screen, sometimes a corrupted screen.

I am flashing with openfpgaloader on a Mac as I don't have Windows machine, and I can't get the GOWIN software to run in a Windows virtual machine.

One difference from he Github instructions is that to update the fw, I have to add

Code: Select all

-f

:

Code: Select all

sudo openFPGALoader -b tangnano9k tn_vdp.fs -f

If anyone has any hints about debugging, I'd like to hear them. I have access to a well outfitted electronics lab.

The second board I built works.

the fpgaLoader should work just fine. If you get the stand alon boot screen it is working. There is no such thing as running a bothed version. Either work or not.

Now my questions:

what are the jumpers you are setting on the board ? I asked before this is very important: nabu needs cpuclk and gromclk closed (shorted, on)

Do you have any other thing connected to the nabu ? try disconnecting, like floppy card, serial adapter etc.

Did you get the version with the diode ? Can you post pictures ?

What happens when you press reset on front panel of nabu ?

Are you using what board ? there are many, did you get the vga version (v1) ? Is the vga outputting ?

if you are using the board version 2, try the last versions I submitted today.