ST STM32F105 series

DocID13902 Rev 15 372/1128
RM0008 General-purpose timers (TIM2 to TIM5)
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Figure 118. Counter timing diagram, Update event with ARPE=1 (counter underflow)
Figure 119. Counter timing diagram, Update event with ARPE=1 (counter overflow)
15.3.3 Clock selection
The counter clock can be provided by the following clock sources:
• Internal clock (CK_INT)
• External clock mode1: external input pin (TIx)
• External clock mode2: external trigger input (ETR).
• Internal trigger inputs (ITRx): using one timer as prescaler for another timer, for
example, you can configure Timer1 to act as a prescaler for Timer 2. Refer to : Using
one timer as prescaler for another on page 391 for more details.
00
CNT_EN
Timer clock = CK_CNT
Counter register
Update interrupt flag (UIF)
Counter underflow
Update event (UEV)
01 02 03 04 05 06 0705 04 03 02 0106
Auto-reload preload register
FD 36
Write a new value in TIMx_ARR
Auto-reload active register
FD 36
CK_INT
36
CNT_EN
Timer clock = CK_CNT
Counter register
Update interrupt flag (UIF)
Counter overflow
Update event (UEV)
35 34 33 32 31 30 2FF8 F9 FA FB FCF7
Auto-reload preload register
FD 36
Write a new value in TIMx_ARR
Auto-reload active register
FD 36
CK_INT