Advanced-control timers (TIM1)
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Figure 173. Dead-time waveforms with delay greater than the positive pulse
The dead-time delay is the same for each of the channels and is programmable with the
DTG bits in the TIMx_BDTR register. Refer to
Section 20.4.18: TIM1 break and dead-time
for delay calculation.
Re-directing OCxREF to OCx or OCxN
In output mode (forced, output compare or PWM), OCxREF can be re-directed to the OCx
output or to OCxN output by configuring the CCxE and CCxNE bits in the TIMx_CCER
register.
This allows you to send a specific waveform (such as PWM or static active level) on one
output while the complementary remains at its inactive level. Other alternative possibilities
are to have both outputs at inactive level or both outputs active and complementary with
dead-time.
Note:
When only OCxN is enabled (CCxE=0, CCxNE=1), it is not complemented and becomes
active as soon as OCxREF is high. For example, if CCxNP=0 then OCxN=OCxRef. On the
other hand, when both OCx and OCxN are enabled (CCxE=CCxNE=1) OCx becomes
active when OCxREF is high whereas OCxN is complemented and becomes active when
OCxREF is low.
20.3.16 Using the break function
The purpose of the break function is to protect power switches driven by PWM signals
generated with the TIM1 timer. The two break inputs are usually connected to fault outputs
of power stages and 3-phase inverters. When activated, the break circuitry shuts down the
PWM outputs and forces them to a predefined safe state.
When using the break functions, the output enable signals and inactive levels are modified
according to additional control bits (MOE, OSSI and OSSR bits in the TIMx_BDTR register,
OISx and OISxN bits in the TIMx_CR2 register). In any case, the OCx and OCxN outputs
cannot be set both to active level at a given time. Refer to
Table 116: Output control bits for
complementary OCx and OCxN channels with break feature on page 535
for more details.
The source for BRK can be:
•
An external source connected to the BKIN pin
•
An internal source: COMP4 output
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