My customer encounted an abnormal GPIO input state on ADuC7023 under specific conditions.
The customer used P0.1(Pin#22) of ADuC7023 as 'GPIO input' and 0x8ea00 to 0x8f5ff of internal flash memory as the user data area. The customer also used BM = 1 and 0x80014=default value at power on reset and set the GPIO input register of P0.1 by user initial code.
Under normal operation, there was no problem with P0.1 as GPIO input, but when the customer wrote user data in flash memory(0x8ea00 to 0x8f5ff), P0.1 was always detected as high or low regardless of the external input level.
The symptom occured randomly and only was found on some ADuC7023 devices(approximately 9%).
Please advice what is the cause of the above symptome ? How should the customer fix it ?