exxos's Atari, Amiga & retro forum

Badwolf wrote: 12 Jul 2024 16:19 Of course, there are different versions of EmuTOS (country codes, ROM sizes, releases). Certain ones don't even support TT-RAM.

I'm using the 256K version. So I would assume it supports TTram. But as my build of TOS206 isn't finding the RAM either.. its likely a hardware problem.

You're completely free of AUTO folder programs, I take it? BLITFIX will simply turn off Blitter in some circumstances, IIRC.

Only HDriver in AUTO, but I have just renamed that as takes to long to load from floppy.

PS YAARTTT has a hidden memory setting, BTW. Press 'M' at the menu and you can enter a block to test. Eg. 01000000 to 02000000.

Thanks that saves me looking up the letter now.. I just copied it to a floppy to run it to see if I can make anything out that way.


EDIT:

All FFs.

Are the buffers are enabled?

BW

Badwolf wrote: 12 Jul 2024 16:29 Are the buffers are enabled?

I see the enable pulsing low, so should be good.

You've got the DIR pin going the right way? ;-)

stephen_usher wrote: 12 Jul 2024 16:45 You've got the DIR pin going the right way? ;-)

No DIR pin on the 74CT3T3245s. It's part of their magic.

BW

exxos wrote: 12 Jul 2024 16:42 I see the enable pulsing low, so should be good.

That's promising. Implies the address decoding's working.

Any activity on the DQM pins?

BW

Badwolf wrote: 12 Jul 2024 16:53 Any activity on the DQM pins?

I tried DQML and its pulsing low. under-overshoot is a bit rubbish, but dont think thats it.

exxos wrote: 12 Jul 2024 17:05

Badwolf wrote: 12 Jul 2024 16:53 Any activity on the DQM pins?

I tried DQML and its pulsing low. under-overshoot is a bit rubbish, but dont think thats it.

So one of the DQMs is going low, the buffers are going low & the CPU's not hanging. Suggests a timing (eg. STERM being asserted too soon) or physical disconnect issue then.

YAARTT is only reporting odd words -- perhaps the high chip is working.

Do you ahve SYSINFO about? That can dump memory at 0x01000000. If every other word is OK, could jsut be a dodgy joint on the low chip.

BW

Badwolf wrote: 12 Jul 2024 17:08 YAARTT is only reporting odd words -- perhaps the high chip is working.

I did wonder that, but I also had RAM problems on the other board as well...

Do you have SYSINFO about? That can dump memory at 0x01000000. If every other word is OK, could just be a dodgy joint on the low chip.

I think I have it somewhere... but what I might do is just boot up STOS and do a routine to just loop a address to see the binary output. Then I can poke about see if anything changes.

EDIT:

Sysinfo just shows FF for the TTram . This was after I let it run YAART for a few seconds to get some data in RAM. So seems the RAM is totally dead :(

I checked the databus and CPU side there is activity.


On the SDRAM side I get this.. And is easily changeable "by finger". But even so, the CPU should be driving some data to the thing :roll:


I budged a pull-up on a dataline and its just sat high all the time. RAMOE is triggering fine, its coded to RAM access. So its like data is going INTO the buffers, but not going OUT :WTF:

I don't get it. Its a copy of the ST536 which worked fine. So I don't think its a code problem. I don't think there was any parts changes on the STE536. So hardware should be the same. PCB layout if different, but I can't see how it could have that much effect to totally kill the RAM. So I don't get it unless the buffers are all faulty or something :(

EDIT:

I'm pretty sure the buffers are not supposed to be 74VHC245 :roll: