Hi Ruud,
Ruud <ruud.baltissen@abp.nl> wrote:
> You can connect a 6821 directly to the bus of a C64, but you can NOT with a
> 6522. This has to do with the fact that the addressbus must be stable when
> CLK2 goes (H). One trick to connect a 6522 to a C64 is delaying the rising
Exactly, the setup time of the adress bus is too high. And if I remember
correctly, this is true for the 6821, too (at least, from the data sheet; it
might be that real chips "behave better" than this!).
> IIRC the original C= IEEE-interface uses a 6525, isn't it? If so, you can
> share the 6525 amongst the above IC.
I must admit I don't know anything about the 6525. ;-)
Spiro.
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