[Coco] Some may call this heresy

[RETRO Innovations]

On 5/28/2018 11:27 PM, CoCo Demus wrote:
> Nope, the 6510 generates a read before a write and I don't understand why.
> I couldn't get a reliable read/write on same port so I messed around using
> a ROM chip to decode:
>
> IO2|R/W|A7-A0
Maybe it's the RMW behavior of the 6502:

http://forum.6502.org/viewtopic.php?t=2

Why is the read before the write a problem?