Author Topic: An address generator  (Read 2230 times)

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Online Alex Eisenhut

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An address generator
« on: October 29, 2021, 07:28:59 pm »
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?
« Last Edit: October 29, 2021, 08:47:47 pm by Alex Eisenhut »
Hoarder of 8-bit Commodore relics and 1960s Tektronix 500-series stuff.
 

Offline Benta

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Re: An address generatorlock,
« Reply #1 on: October 29, 2021, 08:21:26 pm »
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.
 

Online Alex Eisenhut

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Re: An address generator
« Reply #2 on: October 29, 2021, 08:48:12 pm »
The 6502 might be simple, but the system it's in might be crap.
Hoarder of 8-bit Commodore relics and 1960s Tektronix 500-series stuff.
 


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