W65C816SXB behaving strangely on access to memory above FFFF

[tmr4]

Dr Jefyll wrote:

But is it the Rev C board you prefer?

Yes, unless the Rev B board was discounted, then I'd get that. I've seen images of the Rev C board so I know that they're available somewhere.

I already have the W65C256SXB board so I really only want the 816 board as a reference to compare with my own build, including non-BANK 0 memory access. Right now I'm particularly interested in comparing WDC's bank latch implementation against alternatives as I've seen other builds where the 74HC573 proved not fast enough to latch the bank byte. You'd figure a WDC board would get it right, but I guess this post shows that they're about as good as they've always been.

Dr Jefyll wrote:

If so, and you end up with a Rev B instead, you could follow Spacecoaster's suggested mod procedure to create your own Rev C -- it doesn't sound too difficult.

Agree, though I'm not sure I'd do the mod to pin 38 of XBUS just for testing.

Edit (3/8/22): I received the Rev C board from WDC via Amazon.

[Sheep64]

SpaceCoaster on Sun 6 Mar 2022 wrote:

The Rev C. schematic has a December 15 2020 date. Just after this conversation started.

It never occurred to me that the Western Design Center lurks on the 6502 Forum.