ST72321BXXX-AUTO Datasheet, PDF (242/247 Pages) STMicroelectronics – 8-bit MCU for automotive with 32 to 60 Kbyte Flash/ROM, ADC, 5 timers, SPI, SCI, I2C interface

Known limitations
ST72321Bxxx-Auto
jrne OUT
call call_routine
; call the interrupt routine
RIM
OUT:
RIM
JP while_loop
.call_routine
; entry to call_routine
PUSH A
PUSH X
PUSH CC
.ext1_rt
; entry to interrupt routine
LD A,#$00
LD sema,A
IRET
22.1.3
Note:
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.
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
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