Hello! Mia Magnusson wrote: > Btw it would be a good idea to once and for all agreee on a way to read > a specific address in the firmware rom to determine if the card has a > 6523 or an 8255. (This of course applies to the 8088 board. I see no > reason for making the Z80 board with a 6523 at all, thus there is no > reason for differentiation of any software. Good idea. I think a value could be put somewhere around the F000:FFEx location to indicate it's a 8255 card (there is obviously a FF value in the original BIOS). > Btw I assume the idea from Commodore were that the built in Kernal code > for talking with the 8088 card should work with the Z80 card too. Yes. The Kernal implements a certain IPC protocol, and as long as the card conforms to it, it really doesn't care what is on the other side. For what it's worth, you could even create some little hardware to place an another computer over there. > There might be a need for 6509 software to determine if it's a Z80 or > an 8088 card in the machine though. I wounder how or even if Commodore > ment that to work? I am not sure such distinction is needed. The 6509 library implements some functions like "print out a character" or "read sector from disk". Again it really doesn't care which processor called this funcion. And if you really need to do something different for one processor, you would simply write a different version of the library? > Does the 6509 software start the coprocessor and > first talk to it via the 6526/6523 interface and get some ID thing from > the coprocessor to determine if the 6509 software fits the installed > card? The 6509 sends an IRQ to the coprocessor, and enters an infinite loop - it doesn't do anything else. It's up to the coprocessor to call it back requesting some I/O function. Regards, MichauReceived on 2018-06-27 16:00:04
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