STM8S datasheet(170/467 Pages) STMICROELECTRONICS

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16-bit advanced control timer (TIM1)

RM0016

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DocID14587 Rev 14

PWM input signal measurement

This mode is a particular case of input capture mode (see Figure 65). The procedure is the

same except:

•

Two ICi signals are mapped on the same TIi input

•

These two ICi signals are active on edges with opposite polarity

•

One of the two TIiFP signals is selected as trigger input and the clock/trigger controller

is configured in trigger reset mode.

Figure 65. PWM input signal measurement

Procedure

Depending on the fMASTER frequency and prescaler value, the period (in the TIM1_CCR1

be applied on TI1 using the following procedure:

Select the active input capture or trigger input for TIM1_CCR1 by writing the CC1S bits

to 01 in the TIM1_CCMR1 register (TI1FP1 selected).

Select the active polarity for TI1FP1 (used for both capture and counter clear in

TIMx_CCR1) by writing the CC1P bit to 0 (TI1FP1 active on rising edge).

Select the active input for TIM1_CCR2 by writing the CC2S bits to 10 in the

TIM1_CCMR2 register (TI1FP2 selected).

Select the active polarity for TI1FP2 (used for capture in TIM1_CCR2) by writing the

CC2P bit to 1 (TI1FP2 active on falling edge).

Select the valid trigger input by writing the TS bits to 101 in the TIM1_SMCR register

(TI1FP1 selected).

Configure the clock/trigger controller in reset mode by writing the SMS bits to 100 in the

TIM1_SMCR register.

Enable the captures by writing the CC1E and CC2E bits to 1 in the TIM1_CCER1

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