STM32W108CBU6 STMICROELECTRONICS [STMicroelectronics], STM32W108CBU6 Datasheet - Page 97

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

STM32W108CB, STM32W108HB
Because the buffer registers are only transferred to the shadow registers when an update
event occurs, before starting the counter initialize all the registers by setting the TIM_UG bit
in the TIMx_EGR register.
OCy polarity is software programmable using the TIM_CCyP bit in the TIMx_CCER register.
It can be programmed as active high or active low. OCy output is enabled by the TIM_CCyE
bit in the TIMx_CCER register. Refer to the TIMx_CCER register description in the
Registers section for more details.
In PWM mode (1 or 2), TIMx_CNT and TIMx_CCRy are always compared to determine
whether TIMx_CCRy ≤ TIMx_CNT or TIMx_CNT ≤ TIMx_CCRy,depending on the direction
of the counter. The OCyREF signal is asserted only:
●
●
This allows software to force a PWM output to a particular state while the timer is running.
The timer is able to generate PWM in edge-aligned mode or center-aligned mode
depending on the TIM_CMS bits in the TIMx_CR1 register.
PWM edge-aligned mode: up-counting configuration
Up-counting is active when the TIM_DIR bit in the TIMx_CR1 register is low. Refer to
counting mode on page
The following example uses PWM mode 1. The reference PWM signal OCyREF is high as
long as TIMx_CNT < TIMx_CCRy, otherwise it becomes low. If the compare value in
TIMx_CCRy is greater than the auto-reload value in TIMx_ARR, then OCyREF is held at 1.
If the compare value is 0, then OCyREF is held at 0.
PWM waveforms in an example, where TIMx_ARR = 8.
Figure 31. Edge-aligned PWM waveforms (ARR = 8)
PWM edge-aligned mode: down-counting configuration
Down-counting is active when the TIM_DIR bit in the TIMx_CR1 register is high. Refer to
Down-counting mode on page 85
When the result of the comparison changes, or
When the output compare mode (TIM_OCyM bits in the TIMx_CCMR1 register)
switches from the "frozen" configuration (no comparison, TIM_OCyM = 000) to one of
the PWM modes (TIM_OCyM = 110 or 111).
83.
Doc ID 16252 Rev 2
for more information.
Figure 31
shows some edge-aligned
General-purpose timers
Up-
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