exxos's Atari, Amiga & retro forum

I'm on the latest TF image (that I can find on the threads here) and with the very same OS image and TF firmware version it worked (with the UltraSATAN disconnected) until I made the change.

With Carrier Command I manage to load the game but the sampled music stutters as the virtual floppy is re-read as if it's getting read errors and retrying. Swap over to the 68000 (by changing the jumper and restarting) and it works perfectly. I could understand corrupt data getting to the CPU but not the floppy sub-system thinking that it's having read errors.

Actually, I think I'll wait until I swap out the DMA chip when the replacement arrives and see what happens.

Just in case, I added the 1K resistors to the 7406 chip, even though the Goex is supposed to have the pull-ups and it made no difference.

Well, after measuring the maximum I can decrease the height of the stack I'm still going to be approximately 3mm too tall to fit the keyboard, so there's no chance of a system all contained in the original case, unfortunately. So, it's going to have to be a top case with the keyboard holes filled plus building an external keyboard housing.

stephen_usher wrote: 30 Nov 2020 11:50 Well, after measuring the maximum I can decrease the height of the stack I'm still going to be approximately 3mm too tall to fit the keyboard

Even if you dispense with the socket and solder the TF board directly on? (Although I suppose with the layout which tucks the 68K underneath the TF, this may not work.) The only way I could make my own switcher fit in the Stacy was to solder the TF, after lots and lots of testing. ;)

Yes, the 68000 adds a little as there's a 1mm thick resistor on the bottom of the TF which hits it, but that would only be 1mm and I need 3mm.

I'm now thinking of a 68030 relocator board which fits flush to the TF surface, but there are a load of resistors under the socket there. The alternative is to try to build up the SMD 68030 board. Even then it's possibly a mm or more too tall.

Replaced the 2.2K ohm pull ups with 4.7K ones and now the TF can actually read floppies reliably again.

OK, not quite fully corruption free. There are still a few duff bits replaying the Carrier Command samples, you can hear a few crackly bits in the music.

Maybe something is having difficulty pulling the lines low enough fast enough at that far end of the board. The TF's 68030, being CMOS would have a lower voltage for logical low than the NMOS 68000, which isn't affected by the issue, even though the difference in track length is tiny.

Hmm... PAK/3 TOS still crashes when trying to boot HDDriver from the UltraSATAN since the bus pull-ups were changed from 10K ohm. It's all very strange.

I'm putting this project on hold until the SMD 68030 processors arrive from China, which may be as late as February.

stephen_usher wrote: 02 Dec 2020 13:28 I'm putting this project on hold until the SMD 68030 processors arrive from China, which may be as late as February.

Is that the ceramic QFP one? I’ve one sitting around from an aborted card revision I could send you over if you’d like? You can send me one back when it arrives in the new year.

PM me if interested.

BW.