RM0016 16-bit advanced control timer (TIM1)
Doc ID 14587 Rev 8 177/449
Re-directing OCiREF to OCi or OCiN
In output mode (forced, output compare, or PWM), OCiREF can be re-directed to the OCi or
OCiN outputs by configuring the CCiE and CCiNE bits in the corresponding TIM1_CCERi
registers. This means bypassing the deadtime generator which allows a specific waveform
(such as PWM or static active level) to be sent on one output while the complementary
output remains at its inactive level. Alternative possibilities are to have both outputs at
inactive level or both outputs active and complementary with deadtime.
Note: When only OCiN is enabled (CCiE = 0, CCiNE = 1), it is not complemented and becomes
active as soon as OCiREF is high. For example, if CCiNP = 0 then OCiN = OCiREF. On the
other hand, when both OCi and OCiN are enabled (CCiE = CCiNE = 1), OCi becomes active
when OCiREF is high whereas OCiN is complemented and becomes active when OCiREF
is low.
Six-step PWM generation for motor control
When complementary outputs are implemented on a channel, preload bits are available on
the OCi M, CCi E and CCi NE bits. The preload bits are transferred to the active bits at the
commutation event (COM). This allows the configuration for the next step to be programmed
in advance and for configuration of all the channels to be changed at the same time. The
COM event can be generated by software by setting the COMG bit in the TIM1_EGR
register or by hardware trigger (on the rising edge of TRGI).
A flag is set when the COM event occurs (COMIF bit in the TIM1_SR register) which can
generate an interrupt (if the COMIE bit is set in the TIM1_IER register).
Figure 76 shows the behavior of the OCi and OCi N outputs when a COM event occurs, for
three different examples of programmed configurations.
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