STM32W108CBU6 STMICROELECTRONICS [STMicroelectronics], STM32W108CBU6 Datasheet - Page 89

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

STM32W108CB, STM32W108HB
Internal clock source (CK_INT)
The internal clock is selected when the slave mode controller is disabled (TIM_SMS = 000 in
the TIMx_SMCR register). In this mode, the TIM_CEN, TIM_DIR (in the TIMx_CR1
register), and TIM_UG bits (in the TIMx_EGR register) are actual control bits and can be
changed only by software, except for TIM_UG, which remains cleared automatically. As
soon as the TIM_CEN bit is written to 1, the prescaler is clocked by the internal clock
CK_INT.
Figure 21
without prescaling.
Figure 21. Control circuit in Normal mode, internal clock divided by 1
External clock source mode 1
This mode is selected when TIM_SMS = 111 in the TIMx_SMCR register. The counter can
count at each rising or falling edge on a selected input.
Figure 22. TI2 external clock connection example
For example, to configure the up-counter to count in response to a rising edge on the TI2
input, use the following procedure:
1.
2.
Configure channel 2 to detect rising edges on the TI2 input by writing TIM_CC2S = 01
in the TIMx_CCMR1 register.
Configure the input filter duration by writing the TIM_IC2F bits in the TIMx_CCMR1
register (if no filter is needed, keep TIM_IC2F = 0000).
shows the behavior of the control circuit and the up-counter in normal mode,
Doc ID 16252 Rev 2
General-purpose timers
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