SPC564Axx/SPC56ELxx exception cases

AN4417

16/22

DocID025623 Rev 2

3.1.8

User exception handler

Handler has to analyze the following:

•

Type of access, instruction fetch, data read, and data write. Only instruction fetch or

data read access are expected in case of 2b ECC Flash error.

•

Memory range

Memory access must be within area belonging to the Flash memory. User has to know

which part belongs to the code flash and which part belongs to the data flash memory.

3.1.9

Error solving

Flash 2b ECC error can be solved only with erase of the flash sector containing the cell with

2b ECC error. It is usually not done in the exception handler itself, because it takes

significant amount of time.

The decision what to do in case of 2b ECC error is application specific, Whether if to go to

degraded mode or to continue, the case of EEPROM emulation, and to solve the issue later

in the application.

If the decision is to continue, user handler has to request modification of the MCSRR0

register to continue the program flow with next instruction. Otherwise program would be

stuck in the reading of the fault flash address invoking machine checks.