Did you mean that W4 was garbled regardless of 12MHz or 16MHz, but at W6 it was fine at 12MHz? My apologies, yes that is what I meant to write (I was jumping around between working on the 6309/6809 issue and this other issue and was getting a bit careless with my typing). I don't have any AHCT devi...

When I shifted to the W6 setting I had the same garbled screen regardless of whether I had the 12 MHz or 16 MHz clock. With the W4 setting things worked fine with the 12 MHz clock but would sometimes seemed to ignore commands sent to the VDP (but the screen would not be garbled). In other news, I wa...

also try going to the W4 write-delay jumper (instead of W6), when you are running faster DRAM etc. That just seemed to result a mess on the screen. I'll note that the effect I'm seeing doesn't feel like it is associated with the memory side of things i.e. the display is fine; it's just as if it doe...

Thanks David - that's great! The nac_notes.txt file is really useful as it tracks many of the issues I went through as well (albeit taking slightly different paths for the MECB as it doesn't have any way to re-map memory - so it is limited to Level 1 I believe; also my SD card interface is closely m...

Okay, you've got me confused now It does my head in every time - it's even more confusing when they have multiple embedded ifs e.g. when defining what source to include for the different variants of platforms that it can run on. I "think" it is like a BNE i.e. it tests for a non-zero. In ...

Actually, now that I think about it - OS-9 did recognise that I had a 6309 (but running in 6809 mode) so I assume that it must be OK? I checked the VDP RAM and I do have the TMS4464-10NL variants. I only have the 74HCT chips so AHCT ones might be worth checking ... oh, but hold on, I completely miss...

Oh wait, there isn't even any COCO-specific code - it just uses the same code-base as everything else. I guess I need to check in that path then ... hmm, that brings up gazillions of hits :-( I must say, I really don't like the way the defines work as I always get the logic wrong e.g. IFNE H6309 tfr...

So a quick diff between the two folders reveals no differences in the level 1 NitrOS9 source code for the 6809 and 6309 versions of NitrOS9 for the COCO. The 6309 version simply refers to the 6809 makefiles but defines H6309=1 as well. So now I need to check how that define is used (at least I know ...

Fantastic!

Love that "Initial Comment"!

Good luck ... sending good vibes across the Tasman!

LOL, I didn't even know such a thing existed - when I get a chance I'll read up a bit more about it to see what is involved (time is always a barrier for me) - thanks for pointing it out. Good luck with your entry - it's a great way to increase awareness of the Digicool MECB platform for sure!