With 8080 RST7 is free (bus to 1s using pullups) if you want any other you need to assert that on the bus
an octal bus driver with the inputs set to RST3 or 4 is suggested.? RST6 is also in a sorta sometimes
used space as well.?
DDT is a very compact program as well.
heath H8 the front panel was a source of issue for later software.? It was its weakness in the works
of Altair and IMSAI .? Both of them the lights for address were just buffers address the Data leds?
were also same and the processor wait stated between operations.
Most of the "smart" front panels the address leds were again off the address bus
but the data was a latched port? both input and output and the very small usually 256 bytes?
program interrogated switches or loaded the latch. Most all avoided interrupts as they were
difficult (who knows what CPU) and often got in the way.? When running the leds show data
and address off the bus and the FP know if it was running or suspended.
the 8080 FPs often used tricks like 1802 DMA load mode save for it was done via wait and?
jamming nop or jumps for a single cycle.
Allison
