UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 316

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

(4) Capture register (CR22/CR22W)
(5) Edge detection circuit
(6) Output control circuit
(7) Prescaler
(8) Selector
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CR22/CR22W is an 8/16-bit register that captures the contents of TM2/TM2W.
The capture operation is synchronized with the input of a valid edge to the external interrupt request input pin
(INTP1)(capture trigger). The contents of the CR22/CR22W register are retained until the next capture trigger is
generated. Also, TM2/TM2W can be cleared after a capture operation.
This capture register operates as CR22 in the 8-bit mode, and CR22W in the 16-bit mode.
CR22/CR22W 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.
This circuit generates an external interrupt request (INTP1) and capture trigger by detecting the valid edge of the INTP1
pin input specified by the external interrupt mode register 0 (INTM0). It also generates a capture trigger, the count
clock of an external event, and external interrupt request (INTP2) by detecting the valid edge from an external interrupt
request input pin (INTP2).
It is possible to invert the timer output when the CR20/CR21 register contents and the contents of TM2 match or the
CR20W/CR21W contents and the contents of TM2W match.
A square wave can be output from the timer output pins (TO2/TO3) in accordance with the setting of the high-order
4 bits of the timer output control register (TOC). At this time, PWM output or PPG output can be performed according
to the specification of the capture/compare control register 2 (CRC2).
Timer output can be disabled/enabled by means of the TOC register. When timer output is disabled, a fixed level is
output to the TO2 and TO3 pins (the output level is set by the TOC register).
The prescaler generates the count clock from the internal system clock. The clock generated by the prescaler is selected
by the selector, and is used as the count clock by the timer register 2 (TM2/TM2W) 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 2 (TM2/TM2W).
CHAPTER 10 TIMER/COUNTER 2