
CHAPTER 7 TIMER/COUNTER FUNCTION
User’s Manual U12768EJ4V1UD
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(2) Capture/compare registers 00, 10 (CR00, CR10)
CRn0 is a 16-bit register that functions as a capture register and as a compare register. Whether this register
functions as a capture or compare register is specified by using bit 0 (CRCn0) of the CRCn register.
(a) When using CRn0 as compare register
The value set to CRn0 is always compared with the count value of the TMn register. When the values of the
two match, an interrupt request (INTTMn0) is generated. When TMn is used as an interval timer, CRn0 can
also be used as a register that holds the interval time.
(b) When using CRn0 as capture register
The valid edge of the TIn0 or TIn1 pin can be selected as a capture trigger. The valid edge of TIn0 or TIn1 is
set by using the PRMn register.
When the valid edge of the TIn0 pin is specified as the capture trigger, refer to Table 7-2. When the valid
edge of the TIn1 pin is specified as the capture trigger, refer to Table 7-3.
Table 7-2. Valid Edge of TIn0 Pin and Capture Trigger of CRn0
ESn01
ESn00
Valid Edge of TIn0 Pin
CRn0 Capture Trigger
0
Falling edge
Rising edge
0
1
Rising edge
Falling edge
1
0
Setting prohibited
1
Both rising and falling edges
No capture operation
Remark
n = 0, 1
Table 7-3. Valid Edge of TIn1 Pin and Capture Trigger of CRn0
ESn11
ESn10
Valid Edge of TIn1 Pin
CRn0 Capture Trigger
0
Falling edge
0
1
Rising edge
1
0
Setting prohibited
1
Both rising and falling edges
Remark
n = 0, 1
CRn0 is set by using a 16-bit memory manipulation instruction.
These registers can be read/written when used as compare registers and can only be read when used as
capture registers.
RESET input sets this register to 0000H.
Caution
In a mode in which the timer is cleared and started on a match between TMn and CRn0,
set the CRn0 register to other than 0000H. In the free-running mode or the TIn0 valid
edge clear mode, however, an interrupt request (INTTMn0) is generated after an overflow
(FFFFH) when CRn0 is set to 0000H.