CHAPTER 7 TIMER/COUNTER FUNCTION
User’s Manual U13850EJ4V0UM
177
(2) Capture/compare registers n0 (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 for TIn0 or TIn1
is set by using the PRMn0 register.
When the valid edge for TIn0 pin is specified as the capture trigger, refer to
Table 7-2.
When the valid edge
for 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
0
Falling edge
Rising edge
0
1
Rising edge
Falling edge
1
0
Setting prohibited
Setting prohibited
1
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
0
Falling edge
Falling edge
0
1
Rising edge
Rising edge
1
0
Setting prohibited
Setting prohibited
1
1
Both rising and falling edges
Both rising and falling edges
Remark
n = 0, 1
CRn0 is set by using a 16-bit memory manipulation instruction.
The value of this register is undefined after the RESET signal is input.
Caution Set CRn0 to a value other than 0000H in the clear & start mode entered upon a match between
TMn and CRn0. In the free-running mode or the TIn0 valid edge clear mode, however, an
interrupt request (INTTMn0) is generated after an overflow (FFFFH) when 0000H is set to CRn0.
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