GD32F10x User Manual
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TIMERx_CHxCV register, at the same time the CHxIF bit is set and the channel interrupt is
generated if enabled by CHxIE = 1.
Figure 15-72. Channels
input capture principle
CI0
Synchronizer
D
presclare
Capture
Register
(
CH0VAL
)
Clock
Processer
Counter
TIMER_CK
Q
Filter
D
Q
D
Q
Edge Detector
ITS
CH0MS
CH0IF
CH0IE
CH0_CC_I
TIMERx_CC_INT
Capture INT From Other Channal
CH0CAPPSC
Edge selector
&inverter
Based on
CH0P&CH0NP
CI0FE0
Rising/Falling
ITI0
ITI3
ITI1
ITI2
CI0FED
Rising&Falling
IS0
CI0FED
First, the channel input signal (CIx) is synchronized to TIMER_CK domain, and then sampled
by a digital filter to generate a filtered input signal. Then through the edge detector, the rising
and fall edge are detected. You can select one of them by CHxP. One more selector is for
the other channel and trig, controlled by CHxMS. The IC_prescaler make several the input
event generate one effective capture event. On the capture event, CHxVAL will restore the
value of Counter.
So the process can be divided to several steps as below:
Step1:
Filter configuration. (CHxCAPFLT in TIMERx_CHCTL0)
Based on the input signal and requested signal quality, configure compatible
CHxCAPFLT.
Step2:
Edge selection. (CHxP/CHxNP in TIMERx_CHCTL2)
Rising or falling edge, choose one by CHxP/CHxNP.
Step3
: Capture source selection. (CHxMS in TIMERx_CHCTL0)
As soon as you select one input capture source by CHxMS, you have set the channel
to input mode (CHxMS != 0x0) and TIMERx_CHxCV cannot be written any more.
Step4:
Interrupt enable. (CHxIE in TIMERx_DMAINTEN)
Enable the related interrupt enable; you can got the interrupt.
Step5:
Capture enables. (CHxEN in TIMERx_CHCTL2)
Summary of Contents for GD32F10 Series
Page 63: ...GD32F10x User Manual 63 programmed during the chip production ...
Page 117: ...GD32F10x User Manual 117 010 1 0 011 0 9 ...
Page 416: ...GD32F10x User Manual 416 shadow register updates every update event ...
Page 427: ...GD32F10x User Manual 427 value ...
Page 518: ...GD32F10x User Manual 518 These bits are not used in SPI mode ...