UM0224 datasheet(24/34 Pages) STMICROELECTRONICS

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Running the demonstrations

STR75x demonstration software

24/34

2.4.5

Period measurement

This menu allows you to measure the period of an external input signal. The STR750 timers

can be used in PWMI (PWM input) mode to measure the frequency and the duty cycle of an

input signal in a range which depends on the TIM1 clock: in our case the range is from 458

Hz to 10 kHz. You have to connect the signal to be measured to the TIM1_TI2/P0.31 pin.

If the input signal is in the specified range, the following message is displayed on the LCD:

If the signal is under the low limit of the range, the following message is displayed on the

LCD:

If the signal is over the high limit of the range, the following message is displayed on the

LCD:

If there is no signal connected to the TIM1_TI2/P0.31 pin, the following message is

displayed on the LCD:

Duty Cycle: xx%

Freq: xxxxx Hz

Out of range!!

Freq < 458 Hz

Out of range!!

Freq > 10 kHz

!!no signal!!

Press UP/DOWN

UM0224 Datasheet(PDF) 24 Page - STMicroelectronics