UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 278

• Manufacturer Part Number: UPD784026
• Description: 16/8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

(4) Capture register (CR12/CR12W)
(5) Edge detection circuit
(6) Prescaler
(7) Selector
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CR12/CR12W is an 8/16-bit register that captures the contents of TM1/TM1W.
The capture operation is synchronized with the input of a valid edge (capture trigger) on the external interrupt request input
pin (INTP0). The contents of the CR12/CR12W are retained until the next capture trigger is generated.
This capture/compare register operates as CR12 in the 8-bit operating mode, and CR12W in the 16-bit operating mode.
CR12/CR12W can be read only with an 8/16-bit manipulation instruction. The contents of this register are undefined after
RESET input.
The edge detection circuit detects an external input valid edge.
When the valid edge set by external interrupt mode register 0 (INTM0) is detected in the INTP0 pin input, the external
interrupt request (INTP0), a capture trigger and a count clock of the external event are generated (see Figure 19-1 for details
of the INTM0).
The prescaler generates the count clock from the internal system clock. The clock generated by this prescaler is selected
by the selector, and is used as the count clock by the timer register 1 (TM1/TM1W) to perform count operations.
The selector selects a signal resulting from dividing the internal clock or the edge detected by the edge detection circuit as
the count clock of timer register 1 (TM1/TM1W).
(b) When specified as capture register
CR11/CR11W functions as an 8/16-bit register that captures the contents of TM1/TM1W in synchronization with the
input of a valid edge (capture trigger) on the external interrupt request input pin (INTP0).
The contents of the CR11/CR11W are retained until the next capture trigger is generated. TM1/TM1W can be cleared
after a capture operation.
CHAPTER 9 TIMER/COUNTER 1