Mega ST project

[frank.lukas]

Take the Blitter out ...

[HigashiJun]

You probably already have these but just in case:

PAK Jumpers.jpeg
PAK Diagarm.jpeg
PAK_en.pdf

One of the big things the manual stresses is enough grounding for the bus. It
recommends more than one. I have 3 on mine.

Thank you Darklord, but as you wrote, I have these in my Atari related documents.

[HigashiJun]

@Badwolf @frank.lukas

So the blitter has to be disabled even if I use the PAK68/3 with jumper J5 removed (= PAK disabled) ?

[DoG]

Blitter doesn't matter beyond 32Mhz anyway.

[HigashiJun]

Blitter doesn't matter beyond 32Mhz anyway.

Well, I had the same opinion, but it seems it does matter.

Once the blitter removed, I can access the upper menu without freezing my Mega ST.

It sometimes freezes later, but I guess it is due to the fact I have temporarily "soldered" the two blitter pads with some wire and tape.

[frank.lukas]

I have two machine with PAK68/3 stuff and all work very stable and well ...

What are your pullup resistors for data and address lines? You must remove the Blitter chip.

Ask "pakman" for the latest JED GAL Files over the atari-forum.com ...

[HigashiJun]

I have two machine with PAK68/3 stuff and all work very stable and well ...

What are your pullup resistors for data and address lines? You must remove the Blitter chip.

Ask "pakman" for the latest JED GAL Files over the atari-forum.com ...

The blitter chip is now removed.

My pull-up resistors are all 2.2K.

I have downloaded the last JED files on the wrsonline.de website. Do you mean there are newer ones ?

[frank.lukas]

The blitter chip is now removed.

good

My pull-up resistors are all 2.2K.

too much for my feeling

I have downloaded the last JED files on the wrsonline.de website. Do you mean there are newer ones ?

Holger is working always on it. Ask him ...

Try it with the old JED with 32Mhz or 40Mhz first

[HigashiJun]

The blitter chip is now removed.

good

My pull-up resistors are all 2.2K.

too much for my feeling

I have downloaded the last JED files on the wrsonline.de website. Do you mean there are newer ones ?

Holger is working always on it. Ask him ...

Try it with the old JED with 32Mhz or 40Mhz first

Thank you Frank for this information.

I have already tried the old JEDs (before burning the new ones) with a 32 Mhz oscillator and the result was the same.

I think 2.2K pull-ups are a sweet spot for all STs with modern stuff like Ultrasatan and other. I had my STE booster working great without them, but when I wanted to access my Ultrasatan, a lot of errors occurred.

I am now waiting for the "F" type line drivers to be delivered. They should arrive soon.

[frank.lukas]

PAK FAQ ...

The mainboard RAM is probably too slow; 100ns is the absolute maximum for the current GAL rate, better 80ns; together with a PuPla / 2 the mainboard RAM should be as fast as possible!

The board termination is not sufficient. Especially with a 50MHz PAK clock, the address termination on the board should be 3k3 and the data termination 4k7. Should only appear on older computers (520, 1040), as these are still partially terminated with 10k.

The clock line of the PAK is not terminated correctly or not at all. Unfortunately, the 68030 is quite a mimosa when it comes to the clock. If this is not absolutely clean, there are the greatest problems