Mega ST project

[frank.lukas]

Bei der alten Platinenversion (PAK/3-030) müssen noch einige Leitungen gefädelt werden, da das Layout nur die Versorgung des GALs mit Vcc und GND vorsieht. Die neue Platinenversion (PAK/3-030A) enthält alle nötigen Verbindungen, aber mit einem anderen Pinout!

It say the old pcb has only VCC and GND connected to the GAL U3. You must see the schematics from the PAK ...

[frank.lukas]

PAK.pdf



U3 = puk.jed and not puk_a.jed !

pak_puk.png (76.7 KiB) Viewed 2699 times

[Darklord]

If it helps, here is the English version of the Pak PDF:

PAK_en.pdf

(625.86 KiB) Downloaded 88 times

[HigashiJun]

@frank.lukas @Darklord

Thank you both for your feedback.

I have the English version of the manual, so no worries.

The GAL is the "P3-PUK", so no problem here too.

I thought I had the patch Frank is talking about done on my PAK68, but I have realized the bodge wires are just another patch (see the picture below):

PAK1.jpeg (516.23 KiB) Viewed 2656 times

So I will have to add my thin gauge wire to make the 68000 work.

Hope to have some free time this week-end...

[Darklord]

All of this makes me glad that I wound up with the later version of the Pak board.

It's very interesting to watch you work through these problems. I'm sure they will
submit to your and Franks' technological prowess, in the end!

[Wolfgang]

I ask Idek for a 030 STGA T8 nova driver ...

And here they are. Totally untested since I don't have this setup. But I doubt that it is driver related anyway. The 68000 drivers should also work.

[HigashiJun]

Thank you !

I will give them a try anyway.

[HigashiJun]

Ok, one issue is solved.

The PAK68 now works with a CPU on top of it, so the fallback mode is operational.

As Frank Lukas wrote, the wire patch at the bottom of the board was missing.

Now, it is applied:

PAKpatched.jpeg (490.57 KiB) Viewed 2563 times

Remains the FDD issue...

[HigashiJun]

Some more feedback after some quick tests:

- When the PAK is fitted on the CPU relocator, I get RAM errors on the Atari boot screen.
- Fitted directly on the motherboard, no more RAM errors occur.
- The fallback mode does not work with the MC68HC000 CPU and the PAK simply does not boot with this CPU, even in PAK mode.
- Works great with a MC68000 CPU (fallback mode and PAK mode).
- The FDD works in fallback mode (8 Mhz).
- I have no more error message while accessing the FDD in PAK mode, but only a reboot.

That is all for now...

[frank.lukas]

pm pakman and ask for tips ...