I know nothing of such things, but would it be easier and cheaper to simulate a 6526 using an Atmel controller(s) of some kind? On 10/06/2018 8:33 PM, Gerrit Heitsch wrote: > On 06/10/2018 01:59 PM, Michał Pleban wrote: >> Hello! >> >> smf wrote: >> >>> I assume for cost purposes they don't keep the last output value >>> when in >>> read mode, so when you switch back to output mode then zeros is >>> probably >>> the lesser of two evils. >> >> That might be the case when you switch from input to output, but when >> you "switch" from output to output (i.e. you leave the direction of the >> port unchanged, only modifying some other port) it's just ridiculous. >> >>> Trying to replace a mos chip with an intel chip is blasphemy :-) >> >> Guilty as charged :-) But it's for a good reason: there are only very >> little 6525's laying around, and if we want to make the 8088 card >> accessible to everyone, we had to change to a chip that's readily >> available. > > How about two 6522 instead? With some clever logic and mapping of the > address bits, you might be able to come up with a register map that > comes close to what the 6525 has, limiting the amount of change in the > code. > > Gerrit > > > > >Received on 2018-06-10 15:00:52
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