ST STM32L4+ Series Reference Manual page 1306

General-purpose timers (TIM2/TIM3/TIM4/TIM5)
Figure 345. Counter timing diagram with prescaler division change from 1 to 2
Timerclock = CK_CNT
Counter register
Update event (UEV)
Prescaler control register
Prescaler buffer
Prescaler counter
Figure 346. Counter timing diagram with prescaler division change from 1 to 4
Timerclock = CK_CNT
Update event (UEV)
Prescaler control register
Prescaler counter
1306/2301
CK_PSC
CEN
F7
Write a new value in TIMx_PSC
CK_PSC
CEN
Counter register
Write a new value in TIMx_PSC
Prescaler buffer
F8 F9 FA FB FC
0
0
0
F7 F8 F9
FA FB
0
0
0
RM0432 Rev 6
01
00
1
1
0 1 0
1 0
FC
00
3
3
0 1 2 3 0
RM0432
02 03
1 1
0
MS31076V2
01
1 2 3
MS31077V2