An address generator

[Alex Eisenhut]

The idle thought occurred to me that a possible test of a 6502-based board is to drive the address bus through all states. The usual solution is to strap a "NOP generator" somewhere, but it seems easier to just replace the 6502 with a test harness that drives the address lines. The purpose being to observe the address decoding circuitry on the board.

A 40 pin DIP board with a 16 bit counter connected to the clock, plus whatever is needed for the phase signals.

Does such a thing already exist?

[Benta]

The purpose being to observe the address decoding circuitry on the board.

A 40 pin DIP board with a 16 bit counter connected to the clock, plus whatever is needed for the phase signals.

Does such a thing already exist?

Yes. It's called an in-circuit-emulator (very expensive, though). But I fail to see the real purpose on a system as simple as 6502. Just follow the PCB traces, combined with the 74LS138/139 data sheets.

[Alex Eisenhut]

The 6502 might be simple, but the system it's in might be crap.