STM32W108CBU6 STMICROELECTRONICS [STMicroelectronics], STM32W108CBU6 Datasheet - Page 91

• Manufacturer Part Number: STM32W108CBU6
• Description: High-performance, IEEE 802.15.4 wireless system-on-chip
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

STM32W108CB, STM32W108HB
8.1.4
Figure 24
Figure 24. External trigger input block
For example, to configure the up-counter to count each 2 rising edges on ETR, use the
following procedure:
●
●
●
●
●
The counter counts once each 2 ETR rising edges.
The delay between the rising edge on ETR and the actual clock of the counter is due to the
resynchronization circuit on the ETRP signal.
Figure 25. Control circuit in external clock mode 2
Capture/compare channels
Each capture/compare channel is built around a capture/compare register including a
shadow register, an input stage for capture with digital filter, multiplexing and prescaler, and
an output stage with comparator and output control.
As no filter is needed in this example, write TIM_ETF = 0000 in the TIMx_SMCR
register.
Set the prescaler by writing TIM_ETPS = 01 in the TIMx_SMCR register.
Select rising edge detection on ETR by writing TIM_ETP = 0 in the TIMx_SMCR
register.
Enable external clock mode 2 by writing TIM_ECE = 1 in the TIMx_SMCR register.
Enable the counter by writing TIM_CEN = 1 in the TIMx_CR1 register.
gives an overview of the external trigger input block.
Doc ID 16252 Rev 2
General-purpose timers
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