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Figure 21 Timing Diagram when Setting REPCNT=2 in Count-up Mode
CK_CNT
Counter
overrun
Update
event
Prescaler PSC
The prescaler is 16 bits and programmable, and it can divide the clock
frequency of the counter to any value between 1 and 65536 (controlled by
TMRx_PSC register), and after frequency division, the clock will drive the
counter CNT to count. The prescaler has a buffer, which can be changed during
running.
Input capture
Input capture channel
The advanced timer has four independent capture/compare channels, each of
which is surrounded by a capture/compare register.
In the input capture, the measured signal will enter from the external pin
T1/2/3/4 of the timer, first pass through the edge detector and input filter, and
then into the capture channel. Each capture channel has a corresponding
capture register. When the capture occurs, the value of the counter CNT will be
latched in the capture register CCx. Before entering the capture register, the
signal will pass through the prescaler, which is used to set how many events to
capture at a time.
Input capture application
Input capture is used to capture external events, and can give the time flag to
indicate the occurrence time of the event and measure the pulse jump edge
events (measure the frequency or pulse width), for example, if the selected
edge appears on the input pin, the TMRx_CCx register will capture the current
value of the counter and the CCxIFLG bit of the state register TMRx_STS will be
set to 1; if CCxIEN=1, an interrupt will be generated.