We have been using a pcb with a MK66FN2M0VLQ18 on it for over a year now. At some point today it started acting odd so I tried to flash the device using a JFLASH debugger. The Jflash connected but when i tried to erase and program it gave an error that said, "failed to download ramcode".
I then tried to run the code without downloading in the debugger and saw the MCU was in a fault condition. The fault was that the device could not access the MCU ram. Finally with debugger I tried to simply write a value into ram but it would not work.
Is there some odd mode that will cause the MCU ram to be locked? Does anyone have any idea what this might be caused by?