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Chapter 7 Timer/Counter Units
7
Fig. 7-51 Compare Operation
Remark CLR10 = 0, CLR11 = 0, CM = 0
Caution When using an in-circuit emulator, see the notes described in Section 7.5.4.
Fig. 7-52 TM1 Cleared After a Coincidence Is Detected
(2) Capture operation
Eight-bit timer/counter 1 performs a capture operation to load the count value of the timer into the capture
register in synchronism with an external trigger.
As an external trigger, a valid edge detected on the external interrupt request (INTP0) input pin is used (capture
trigger). In synchronism with a capture trigger, the count value of 8-bit timer 1 (TM1) in count operation is
loaded and held in the capture/compare register (CR11) specified to perform capture operation. Until the next
capture trigger occurs, the value of the CR11 register is held.
A valid edge used as a capture trigger is set using external interrupt mode register 0 (INTM0). When both a
rising edge and falling edge are set as capture triggers, the pulse width of an applied external signal can be
measured. When a capture trigger is generated using one edge, the period of an input pulse signal can be
measured.
For the detailed format of the INTM0 register, see Fig. 11-1 in Chapter 11.
Caution When using an in-circuit emulator, see the notes described in Section 7.5.4.
Coincidence
Count starts
0H
CE11
Coincidence
Value of CR11
Value of CR10
FFH
TM1
count value
INTC10
interrupt request
INTC11
interrupt request
OVF1
CE10
CE11
CLR100
CLR111
CE10
CLR101
CLR110
CR10
CR11
CR10 CR10
TM1
count value
Count starts Cleared Cleared Cleared
Count starts
Count stops
0H
INTC10
interrupt request
INTC11
interrupt request