STM32W108HB datasheet(176/278 Pages) STMICROELECTRONICS

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General-purpose timers

STM32W108HB STM32W108CC STM32W108CB STM32W108CZ

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Doc ID 16252 Rev 14

Hints on using center-aligned mode:

●

When starting in center-aligned mode, the current up-down configuration is used. This

means that the counter counts up or down depending on the value written in the DIR bit

in the TIMx_CR1 register. The DIR and CMS bits must not be changed at the same

time by the software.

●

Writing to the counter while running in center-aligned mode is not recommended as it

can lead to unexpected results. In particular:

●

The direction is not updated the value written to the counter that is greater than the

auto-reload value (TIMx_CNT > TIMx_ARR). For example, if the counter was counting

up, it continues to count up.

●

The direction is updated if when 0 or the TIMx_ARR value is written to the counter, but

no update event is generated.

●

The safest way to use center-aligned mode is to generate an update by software

(setting the UG bit in the TIMx_EGR register) just before starting the counter, and not to

write the counter while it is running.

10.1.10

One-pulse mode

One-pulse mode (OPM) is a special case of the previous modes. It allows the counter to be

started in response to a stimulus and to generate a pulse with a programmable length after

a programmable delay.

Starting the counter can be controlled through the slave mode controller. Generating the

waveform can be done in output compare mode or PWM mode. Select OPM by setting the

OPM bit in the TIMx_CR1 register. This makes the counter stop automatically at the next

update event.

A pulse can be correctly generated only if the compare value is different from the counter

initial value. Before starting (when the timer is waiting for the trigger), the configuration must

be:

●

In up-counting: TIMx_CNT < TIMx_CCRy

≤TIMx_ARR (in particular, 0 < TIMx_CCRy),

●

In down-counting: TIMx_CNT > TIMx_CCRy.

STM32W108HB Datasheet(PDF) 176 Page - STMicroelectronics