Maximilian wrote: ↑Thu Mar 21, 2019 9:29 am
A drawing/detailed description/photo of the modifications you made to the bus arbitration lines would be interesting...
Something like this... Off the top of my head.
adapter schematics.png (199.75 KiB) Viewed 3659 times
A kludge is a workaround or quick-and-dirty solution that is clumsy, inelegant, inefficient, difficult to extend and hard to maintain.
Maximilian wrote: ↑Thu Mar 21, 2019 10:38 am
And both _hlt are now tied together?
Yep
Does diagrom do any serial output with the DIP68000 removed. Thats the first thing to check.
———
"It is not necessarily a supply voltage at no load, but the amount of current it can provide when touched that
indicates how much hurting you shall receive."
terriblefire wrote: ↑Thu Mar 21, 2019 11:36 am
Does diagrom do any serial output with the DIP68000 removed. Thats the first thing to check.
Without the DIP64 CPU in the adapter the machine is dead. So far so good.
Edu Arana suggested to me that I should try pulling the PLCC BR low and the DIP64 BR high as the only modifications. Tried it, and it seems somewhat better. Still weird results, but a bit more repeatable, and I got some other things (graphics!) on the screen.
Still not booting though.
A kludge is a workaround or quick-and-dirty solution that is clumsy, inelegant, inefficient, difficult to extend and hard to maintain.
Could this be the problem?
In the a600 the BR is tied to VPA and those are tied to a 1k resistor.
So if you pull down BR you are also pulling down VPA......not a problem during startup but maybe during normal running?
Also the 1k pullups are a lot stronger then the 470/4k7 ohm resistors on the A500.