CompuServe Messages

Sorry, I can't find anything in the documentation that indicates a good way of fixing a board in a particular address range. The software definable loaction of all PICs and the logic necessary for autoconfiguration certainly get in the way of home brew stuff with this machine. There is one slightly nasty way to get a fixed memory address that won't fight too much with autoconfiguration stuff, at least in current Amigas. What you do is pick an Amiga-reserved memory location that doesn't have anything really in it. This prevents an autoconfigured thing from grabbing your address space the same time you're trying. Then you preform the address detection on your board and lock out internal selection via the overlay (/OVR) input. Now, overlay seems to have a number of problems, the worst being that the timing on this is VERY critical. And its not a really nice way of interfacing to the Amiga, but can do in a pinch. I suppose another solution would be to re-configure anything that conflicts with your board. Essentially, you hook up your fixed address board, set so that a port on it somewhere must be written by you before the thing will respond. Then boot up your Amiga as usual. You look at the add-ons to see if anything is sitting in your chosen location. If it is, you re-configure it so that it goes somewhere else. This could require some tricky software, but it should be a bit more upward compatible than the previous way. I don't know for certain if there's any other way, though I've never read of one. -Hazy