Hardware pin on an A500 to toggle via assembly

[kamiga]

I'm doing some troubleshooting for the replacement A501 card I'm designing and I could use some help.

http://techtravels.org for details on the project(s)

I could really use a hardware pin(or two) to toggle through assembly, and it's not immediately clear to me what's available that would be both easy to call from assembly AND not be disruptive to normal OS processes.

The idea here is that I have some VERY rudimentary memory tests implemented in assembly, and I'd like to trigger my logic analyzer on error or success.

Maybe a pin from the parallel port?

Ideally, there won't be any complicated chip-setup procedure, os libraries to load, or anything.

If I could just add/mov a 1 or a 0 into an address, that would be perfect.

Thanks
kamiga

[psxphill]

Maybe a pin from the parallel port?
 
Ideally, there won't be any complicated chip-setup procedure, os libraries to load, or anything.
 
If I could just add/mov a 1 or a 0 into an address, that would be perfect.

Parallel port is simplest, you just need a couple of move.b to set the port to output and write a byte to the port.

[RedskullDC]

Hi Kamiga,

The idea here is that I have some VERY rudimentary memory tests implemented in assembly, and I'd like to trigger my logic analyzer on error or success.

Maybe a pin from the parallel port?

Ideally, there won't be any complicated chip-setup procedure, os libraries to load, or anything.

If I could just add/mov a 1 or a 0 into an address, that would be perfect.

If you are just testing the memory functionality (RTC appears to work, I just had a look at your web page), you could use the _CLKRD pin (GARY pin 22) as a strobe for your analyser?

Only requires reading the appropriate address range, no lib calls etc. $00DC0001

Cheers,
Red

[kamiga]

Thanks for the replies.

Yes, I'll give the RTC method a try.  So far, everything is passing, and so there's no errors to catch.