So today I found a odd issue.. I have seen it before, but I put it down to the previous problems but this seems to be a new problem, it is difficult to tell if there is still a bad connection or not.. I'm not sure if the board I was testing yesterday and this issue or not, but I will retest later today to make sure.
At some random point generally over half an hour, GB6 locks up without bombs.. HALT on the CPU is going crazy I am not sure why..
I swapped out the 40MHz oscillator for a 38.4MHz one, and this did not change anything. So it is not like speed itself issue here, I think not anyway.
I don't think it is ROM related, as it does just the same if accessing ROM at 8MHz.
OK so it died pretty quick that time, I will try disabling the blitter to see if that helps..
I remember having some odd issues while ago where there was a couple of blitters which did not play nice with the booster, I don't know why, but out of 100s tested which worked fine, I just put it down to some bad blitter chips.. I also have had contact problems with the blitter causing issues in the past.. So I will investigate...
One suspect thing is that BR has a heck of a lot of noise on it.. I guess it could be possible the CPU is seeing a bus request when there actually isn't one..
Or could be possible the slow rise time could falsely be triggering another BR on the CPU.. The CPU is running at around 25ns cycles, if we took a rough figure of BR is still below 1V around 50ns.. then likely as possible random points timings could just trip the CPU into another bus request..
.. and on x10..
Added 1K onto BR..
Faster rise times, but also lot of oscilations on the low part..
It ran for about 90mins with blitter off, no issues, before with blitter on, was getting lockups after 10-20mins. So think I am looking in the right places here..
Now I am trying with blitter on and the 1K pull up on BR to see how long it runs for this time.. possible may need small pF capacitor to help with noise... but will see how it goes...