6-Step Pwm Generation; Figure 79. 6-Step Generation, Com Example (Ossr=1) - ST STM32F100 Series Reference Manual

Advanced-control timer (TIM1)
12.3.14

6-step PWM generation

When complementary outputs are used on a channel, preload bits are available on the
OCxM, CCxE and CCxNE bits. The preload bits are transferred to the shadow bits at the
COM commutation event. The user can thus program in advance the configuration for the
next step and change the configuration of all the channels at the same time. COM can be
generated by software by setting the COM bit in the TIMx_EGR register or by hardware (on
TRGI rising edge).
A flag is set when the COM event occurs (COMIF bit in the TIMx_SR register), which can
generate an interrupt (if the COMIE bit is set in the TIMx_DIER register) or a DMA request
(if the COMDE bit is set in the TIMx_DIER register).
Figure 79
in 3 different examples of programmed configurations.
246/709
describes the behavior of the OCx and OCxN outputs when a COM event occurs,

Figure 79. 6-step generation, COM example (OSSR=1)

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