
EM358x
Rev. 0.4
181
auto-reload value in TIMx_ARR, then OCyREF is held at 1. If the compare value is 0, then OCyREF is held at 0.
Figure 10-22 shows some edge-aligned PWM waveforms in an example, where TIMx_ARR = 8.
Figure 10-22. Edge-Aligned PWM Waveforms (ARR = 8)
10.3.9.2 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 the Down-Counting
Mode section for more information.
In PWM mode 1, the reference signal OCyREF is low as long as TIMx_CNT > TIMx_CCRy, otherwise it becomes
high. If the compare value in TIMx_CCRy is greater than the auto-reload value in TIMx_ARR, then OCyREF is
held at 1. Zero-percent PWM is not possible in this mode.
10.3.9.3 PWM Center-Aligned Mode
Center-aligned mode is active except when the TIM_CMS bits in the TIMx_CR1 register are 00 (all configurations
where TIM_CMS is non-zero have the same effect on the OCyREF/OCy signals). The compare flag is set when
the counter counts up, when it counts down, or when it counts up and down, depending on the TIM_CMS bits
configuration. The direction bit (TIM_DIR) in the TIMx_CR1 register is updated by hardware and must not be
changed by software. Refer to the Center-Aligned Mode (Up/Down Counting) section for more information.
Figure 10-23 shows some center-aligned PWM waveforms in an example where:
TIMx_ARR = 8
PWM mode is the PWM mode 1
The output compare flag is set when the counter counts down corresponding to the center-aligned mode 1
selected for TIM_CMS = 01 in the TIMx_CR1 register
Содержание EMBER EM358 series
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