Hi John
Please note that this SPI SRAM subject it is not documented. Here and there, they are references to it but it is everything very vague and obscure.
When we try by ourselves, everything gets even more confuse because the External Delay itself seems to do not work properly, witch in practice means that we have no way to diagnose the issue.
It is unfair, very frustrating and we spend lots of time in the attempt to understand what's going on, or what we are doing wrong before coming here searching for help.
Now I have returned to the MiniZ Evalution Board and replaced the on-board E2Prom by the 23K256 as they are pin to pin compatible. Booting from SigmaStudio with a single External Delay between input and output, I get exactly the same behavior as in my board:
A) no distortion with some Delay Max values (usually even numbers)
B) heavy distortion with some Delay Max values (usually odd numbers)
C) nothing changes when programing Delay values in the “no distortion cases”.
D) all the SPI signals are clean and OK.
Anyway I am pretty sure that the algorithm will be fixed by Development Team.
The information that will really help me a lot now is simply how to drive the 23K256 !CS pin in a way that my board will be compatible with future fixed SigmaStudio versions in self-booting mode.
Thank you