RM0440 Rev 4 1273/2126
RM0440 General-purpose timers (TIM2/TIM3/TIM4/TIM5)
1343
Figure 403. Pulse generation on compare event, for edge-aligned and encoder modes
This output compare mode is selected using the OC3M[3:0] and OC4M[3:0] bit fields in
TIMx_CCMR2 register.
The pulse width is programmed using the PW[7:0] bitfield in the register, using a specific
clock prescaled according to PWPRSC[2:0] bits, as follows:
t
PW
= PW[7:0] x t
PWG
where t
PWG
= (2
(PWPRSC[2:0])
) x t
tim_ker_ck
.
gives the resolution and maximum values depending on the prescaler value.
The pulse is retrigerable: a new trigger while the pulse is on-going will cause the pulse to be
extended.
Note: If the two channels are enabled simultaneously, the pulses will be issued independently as
long as the trigger on one channel is not overlapping the pulse generated on the concurrent
output. On the opposite, if the two triggers are overlapping, the pulse width related to the 1st
arriving trigger will be extended (because of the re-trigger), while the pulse width of the last
arriving trigger will be correct (as shown on the Figure 404 below).
MSv62347V1
Extended pulsewidth
due to re-trigger
Counter
CMP3
Triggers
tim_ocx
Counter
CMP3
Triggers
tim_ocx
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