ST72324xx-Auto
Known limitations
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
te Product(s 15.5
16-bit timer PWM mode
In PWM mode, the first PWM pulse is missed after writing the value FFFCh in the OC1R
register (OC1HR, OC1LR). It leads to either full or no PWM during a period, depending on
the OLVL1 and OLVL2 settings.
Obsolete Product(s) - Obsole 15.6
TIMD set simultaneously with OC interrupt
If the 16-bit timer is disabled at the same time the output compare event occurs then output
compare flag gets locked and cannot be cleared before the timer is enabled again.
Impact on the application
If output compare interrupt is enabled, then the output compare flag cannot be cleared in the
timer interrupt routine. Consequently the interrupt service routine is called repeatedly.
Workaround
Disable the timer interrupt before disabling the timer. Again while enabling, first enable the
timer then the timer interrupts.
● Perform the following to disable the timer:
– TACR1 or TBCR1 = 0x00h; // Disable the compare interrupt
– TACSR I or TBCSR I = 0x40; // Disable the timer
● Perform the following to enable the timer again:
– TACSR & or TBCSR & = ~0x40; // Enable the timer
– TACR1 or TBCR1 = 0x40; // Enable the compare interrupt
Doc ID 13841 Rev 1
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