ST72321R7-Auto datasheet(238/243 Pages) STMICROELECTRONICS

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Known limitations

ST72321xx-Auto

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Doc ID 13829 Rev 1

22.1.6

Clearing active interrupts outside interrupt routine

When an active interrupt request occurs at the same time as the related flag is being

cleared, an unwanted reset may occur.

Note:

Clearing the related interrupt mask will not generate an unwanted reset.

Concurrent interrupt context

The symptom does not occur when the interrupts are handled normally, that is, when:

●

The interrupt flag is cleared within its own interrupt routine

●

The interrupt flag is cleared within any interrupt routine

●

The interrupt flag is cleared in any part of the code while this interrupt is disabled

If these conditions are not met, the symptom can be avoided by implementing the following

sequence:

Perform SIM and RIM operation before and after resetting an active interrupt request.

Example:

SIM

Reset interrupt flag

RIM

Nested interrupt context

The symptom does not occur when the interrupts are handled normally, that is, when:

●

The interrupt flag is cleared within its own interrupt routine

●

The interrupt flag is cleared within any interrupt routine with higher or identical priority

level

●

The interrupt flag is cleared in any part of the code while this interrupt is disabled

If these conditions are not met, the symptom can be avoided by implementing the following

sequence:

PUSH CC

SIM

Reset interrupt flag

POP CC

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