DocID025333 Rev 1

11/13

AN4367

SPC56EL60xx/SPC56xL70xx exception cases

12

3.1.2

Machine check exception status

3.1.3

User exception handler

Handler has to analyze:

•

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

read access are expected in case of 2bECC 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 to the data flash memory.

3.1.4

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 the thing to be done in the exception handler itself, because it

takes significant amount of time.

It is application specific the decision what to do in case of 2b ECC error, 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 read of the fault flash address invoking machine checks.

Table 5. Flash 2b ECC - machine check exception status

Register

Description

MCSRR0

Address of the instruction that caused the exception. In case of ECC error in the data flash

area, register modification will be most probably needed.

MCSR

Type of operation is highlighted here, instruction fetch, data load or data write.

MCAR

Target address that was accessed, but finished with 2b ECC error. This address can be

used for further analysis.