GARTHWILSON wrote:
It is always safe to go with the datasheet
Generally, for worst case timing that is true. But how many engineers will have dumped the W65C816 for quoting this extremely unrealistic timing, is anyone's guess.
GARTHWILSON wrote:
How much actual delay (in ns) did you find, compared to the datasheet? It would be nice to find out that the margin between the datasheet and the reality is huge.
From memory, address lines were valid something like 5 to 10 ns after phi1. It figures, of course, that the address is simply clocked into a register connected to the relevant pins, so it's not a surprising number either. When I saw the timing in the datasheet, I immediately distrusted it. WDC does not make very good documentation anyway. Quite messy, buggy and inconsistent ...
I think the discrepancy stems from confusion between the conceptual (where phase 1 is an address and control line setup period, and phase 2 is the transfer, i.e. where address and control lines, in principle, only
need to be valid when phase 2 starts) and the implementation.