AN2692

Embedded application aspects

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Restarting reprogramming

When interrupted, it is recommended to restart the reprogramming process from the

beginning (that is erasing and programming).

3.3

Ruggedized aspects

Some embedded applications need to be ruggedized to cope with some market specificities.

Application ruggedization is usually done by following a set of rules defined for each project

(e.g.: power-on self tests).

This section describes hints that are suggested when designing a ruggedized application.

3.3.1

Checksum

Some applications may have routines that are used to reprogram the Flash memory in the

field. For such applications, if the software goes out of control and jumps by mistake to those

routines, there is, theoretically, a possibility that the Flash memory is modified by mistake

during this time. Ruggedization could be done by having a checksum computed over the

entire Flash memory content.

3.3.2

Initialization of unused memory locations

In the unlikely event that the application software is going out of control, unused memory

locations could be initialized to an illegal ST10 opcode. In this event, the processor is

stopped by an illegal opcode trap as soon as the execution code jumps by mistake to an

unused memory location.