I have developed a application with K20 some years ago. I have about 100 devices thas is woriking fine. I have just mounted other batch and devices don't work.
I have noted that old items have PK20N512VLL100 (mask: 2N30D) and new ones have MK20DN512VLL10 (mask: 5N22D).
I can program devices but the SW don't run. In debug mode it goes in:
/* This code can be changed using the CPU component property "Build Options / Unhandled int code" */
It seems an unmanaged interrupt, but I check it and all seems OK.
I need some helps to find the trouble and fix it.