I am starting to wonder if t he PLD is faulty or something. I outputted the SRAM_OE to a IO pin.. it NEVER gets accessed (as expected). I had to disable the DTACK code to get it to boot... BUT.. When I add the DTACK code in which triggers on SRAM_OE access as well (so should never trigger) it then a...

I changed the address to.. [800000..8FFFFF] Again ST boots fine. I loaded STOS.. Tried $40000.. bus error.. so as expected. Tried $8FFFF and got back as expected. So address decoding works fine... IMG_4987.JPG andyet, if I go back to $400000 range.. the ST goes nuts, no video random corruption etc.....

I scoped out the SRAM enable.. and its triggering when the floppy is being accessed for starters.. that isn't right.. Its like its decoding the wrong address.. but if that was the case, ROM decoding and the other registers would fail.. ?! So I wrote some new firmware to pulse the address lines one b...

PhilC wrote: ↑

Wed Apr 01, 2020 7:12 pm

Have a look at Agralunds topic about the TF534, I think he used the TT ram space to get it to work with Tos2.06 and Emutos

I'm not getting that far.. I can't even get TOS to boot with alt-ram enabled

TT RAM is above 16MB mark, for 32bit CPU, not 16bit, so I doubt his work will help.

ALT-RAM seems to be acting strange :roll: Its just SRAMEN = ADDR:[400000..BFFFFF] & !ST_AS; .. It enables the flash and pulses DTACK.. But I no longer get video, I just get a totally white screen, but the machine is actually running because I can hear the floppy drive running, and if I press escape,...

It seems I have a bad connection on the flashy CPU socket somewhere as it died totally :roll: Now I have just gone for the proper H4 install... and now EMUTOS is working fine... so bizarrely this bad connection didn't effect TOS104, but EMUTOS it did :roll: In any case, I can confirm it now seems to...

rubber_jonnie wrote: ↑

Wed Apr 01, 2020 11:29 am

@exxos Is there an IDE building shack for me? I've built so many of late I could do with a bit of a production line

There is only 1 out-building. But I am sure we could rig up some internal benches. There is plenty of room!

With this unit being literally 30 seconds away from me, I took the liberty of arranging a sneak peek look around a few weeks ago... Loads of bays outside for arrivals and distribution. 1.JPG Plenty of shelving space for parts and production. 2.JPG There is even a small building our back for PhilC to...

PhilC wrote: ↑

Wed Apr 01, 2020 6:52 am

I agree, a mega with 120ns ram would give me memory test issues but when changed to 70ns worked fine.

Its odd though as the MMU controls RAM and speed of RAM shouldn't matter could just be down to bus loading or something ,

Wasn't that zombie boat series based in Essex ?

Edit:

https://www.imdb.com/title/tt10404664/

Oh nope, Birmingham.. Well folks there just as bad anyway