Figure 134. Update Rate Examples Depending On Mode And Timx_Rcr Register Settings - STMicroelectronics STM32WLEx Reference Manual

RM0461
In Center aligned mode, for odd values of RCR, the update event occurs either on the
overflow or on the underflow depending on when the RCR register was written and when
the counter was launched: if the RCR was written before launching the counter, the UEV
occurs on the underflow. If the RCR was written after launching the counter, the UEV occurs
on the overflow.
For example, for RCR = 3, the UEV is generated each 4th overflow or underflow event
depending on when the RCR was written.

Figure 134. Update rate examples depending on mode and TIMx_RCR register settings

Counter
TIMx_CNT
TIMx_RCR = 0
UEV
TIMx_RCR = 1
UEV
TIMx_RCR = 2
TIMx_RCR = 3
TIMx_RCR = 3
and
re-synchronization
UEV
Update event: Preload registers transferred to active registers and update interrupt generated
Update Event if the repetition counter underflow occurs when the counter is equal to the auto-reload value.
Counter-aligned mode
UEV
UEV
UEV
(by SW)
Upcounting
(by SW)
RM0461 Rev 5
Advanced-control timer (TIM1)
Edge-aligned mode
Downcounting
(by SW)
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