Re: Apple II Pi

[Daniel Kruszyna <dan@krue.net>]

mdj <mdj.mdj@gmail.com> wrote:
> The chip registers are all understandably 32-bit, with the first 32
> GPIO's mapped to one register set, and the remainder to another. Read
> and write are separate registers, and write is separated again into
> set and clear registers. That's the main annoying part, as that seems
> completely superfluous to me ?

The set and clear registers allow multiple threads of execution to
control different gpio bits without using read-modify-write opertions.
In effect, they allow you to address individual bits.

I'm not familiar with the micro used in the raspberry pi, but all of the
micros I've used that have set and clear registers include them in
addition to a standard write register.

-- Daniel