Re: Strange 8255 behavior

From: Michał Pleban <*lists_at_michau.name*> Date: Sun, 10 Jun 2018 15:44:10 +0200 Message-ID: <5B1D2B2A.6040005@michau.name> · lists_at_michau.name

Hello!

Gerrit Heitsch wrote:

> 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.

That would mean having one more big chip on the PCB, and therefore the
PCB would have to be enlarged and redesigned to accomodate it. Doeable,
but lots of work.

Also, attaching the 65xx chips to the 8088 feels a little bit kludgey to
me (whit the necessity to generate PHI2, CS and R/W signals with correct
timing). The 8255 looks better in this role IMHO.

Regards,
Michau.