They been manufactured already and awaiting courier pickup
I was reading though some suska code for the GLUE. There seems to be a lot of "chaos" over bus request timings in there. Seems its relating to syncing to DTACK with the MMU because of RAM interleaving.. This would actually seem to make sense as when I use GLUE decoding and GLUE DTACK, Things seem to work fine, well for 8MHz anyway. Even TOS206 behaves. Oddly though, GLUE doesn't drive DTACK of course for 206, but it seems to still work fine. So its possible /AS is being monitored as well by GLUE and/or MMU. Its not just relating to BGACK if something is using the bus or not.
It makes me wonder if GLUE's "slow" DTACK control is by design. Problem has always been that GLUE sets DTACK low pretty much at the same time /AS goes low. This isn't a problem for the CPU normally as it doesn't see DTACK until much later. BUT, GLUE also keeps DTACK low right up until the next bus cycle in S2. So DTACK is still low right up until the point the CPU sets /AS low again. Which means its low a LOT longer than its supposed to be. But now I am thinking this is deliberate. In that DTACK is kept low for some other reason, like mentioned in the suska code relating to RAM interleaving.
This would make sense as well why I have to switch to 8MHz on BR also. As if the CPU is accessing ROM, it would slow to 8MHz and decode ROM at 8MHz (not 50MHz) Then all the bus grant stuff is timed as per 8MHz. I don't think its just relating to bus grant timings, I have tried 100's of variations and methods relating to it all. So I think DTACK has to be kept low to mimic the GLUE timings when its about to do do a DMA cycle.
Delaying any signals doesn't do a darn thing. So even trying to mimic the timings of 8MHz simply doesn't work. Problem being I can't drive DTACK ST-side from my current board design (I can in the new one). So I need to prove this idea next. Failing that, I will switch to 8MHz mode during DMA stuff like I do on the STE booster. So either way, the problem *should* get fixed.
Another oddity I ran into a few times on boot up, is the screen is white border and black screen, but with a few random corruption lines running across the screen. BUT, the machine does boot up as I can hear the floppy drive loading GB6 up!