I need after press NMI button detect time before push PC register to stack.
If it will work, I can in this time disable write to ZX memory and push 2b value (PC reg.) to external hardware and after it connect back ZX memory....
After NMI will CPU jump only to adress #66 without any writing to stack.
This is pictures from Z80 CPU datasheet:
I must differ between read instruction cycle and NMI. Any idea ? Via WAIT activity ?