Up and Running

[Grant Stockly]

Originally Posted by Geoff Harrison

Ah yes, that would be a Bad Thing. That's the Read/Write line from the CPU. I don't see anything on the circuit diagram that's not meant to pass through to the motherboard.

Geoff.

Thanks for helping so much Geoff.

The R/W line does not go directly from the 6800 to the motherboard. The GAL decodes the address. If the 6800 wants to READ from the flash or sram, then it puts the external Altair 680 bus in a WRITE mode. If it was in a read mode, then the data buffers from the expansion card memory and the 680 motherboard buffers would clash!

I know that isn't the cause of the problem here, I just wanted to explain it...