STM32F101xx, STM32F102xx, STM32F103xx, STM32F105xx and ...

RM0008
Advanced-control timers (TIM1&TIM8)
2. Configure the channel 1 as follows, to detect rising edges on TI:
– IC1F=0000: no filter.
– The capture prescaler is not used for triggering and does not need to be
configured.
– CC1S=01in TIMx_CCMR1 register to select only the input capture source
– CC1P=0 in TIMx_CCER register to validate the polarity (and detect rising edge
only).
3. Configure the timer in trigger mode by writing SMS=110 in TIMx_SMCR register. Select
TI1 as the input source by writing TS=101 in TIMx_SMCR register.
A rising edge on TI1 enables the counter and sets the TIF flag. The counter then counts on
ETR rising edges.
The delay between the rising edge of the ETR signal and the actual reset of the counter is
due to the resynchronization circuit on ETRP input.
Figure 98.
Control circuit in external clock mode 2 + trigger mode
TI1
CEN/CNT_EN
ETR
Counter clock = CK_CNT = CK_PSC
Counter register 34
35 36
TIF
13.3.20 Timer synchronization
The TIM timers are linked together internally for timer synchronization or chaining. Refer to
Section 14.3.15: Timer synchronization on page 349 for details.
13.3.21 Debug mode
When the microcontroller enters debug mode (Cortex-M3 core halted), the TIMx counter
either continues to work normally or stops, depending on DBG_TIMx_STOP configuration
bit in DBG module. For more details, refer to Section 29.16.2: Debug support for timers,
watchdog, bxCAN and I 2 C.
Doc ID 13902 Rev 9 293/995