Re: Raspberry Pi 3B: /dev/mem mmap GPIO works on earmv7hf but not onaarch64

[Jason Thorpe <thorpej%me.com@localhost>]

> On Feb 18, 2026, at 4:43 PM, Yuri Honegger <yuri.honegger%mailbox.org@localhost> wrote:
> 
> Driving a 8-bit bus at 2MHz will be hard with any abstraction between
> your software and the GPIOs, even with a GPIOACCESS32 (unless
> you only need to write new values at a much much lower rate than 2MHz)

For an AY-3-8910, the 2MHz is about supplying the clock for the PSG’s internal counters.  The bus interface is asynchronous with respect to the clock, and register updates do not beed to be made that frequently.

I assume the desire to use the GPCLK0 output is all about avoiding have to use a separate crystal.

-- thorpej