M34282M2-XXXGP Ver la hoja de datos (PDF) - Renesas Electronics

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M34282M2-XXXGP

SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER

Renesas Electronics 

4282 Group

Table 4 Control registers related to timer

Timer control register V1

at reset : 0002

at RAM back-up : 0002

W

V12 Carrier wave output auto-control bit

V11 Timer 1 count source selection bit

V10 Timer 1 control bit

0 Auto-control output by timer 1 is invalid

1 Auto-control output by timer 1 is valid

0 Carrier wave output (CARRY)

1 Bit 5 of watchdog timer (WDT)

0 Stop (Timer 1 state retained)

1 Operating

Timer control register V2

at reset : 00002

at RAM back-up : 00002

W

V23 Carrier wave “H” interval expansion bit

0 To expand “H” interval is invalid

1 To expand “H” interval is valid (when V22=1 selected)

0 Carrier wave generation function invalid

V22 Carrier wave generation function control bit

1 Carrier wave generation function valid

V21 Timer 2 count source selection bit

0 f(XIN)

1 f(XIN)/2

V20 Timer 2 control bit

0 Stop (Timer 2 state retained)

1 Operating

Note: “W” represents write enabled.

(1) Control registers related to timer

• Timer control register V1

Register V1 controls the timer 1 count source and auto-

control function of carrier wave output from port CARR by

timer 1. Set the contents of this register through register A

with the TV1A instruction.

• Timer control register V2

Register V2 controls the timer 2 count source and the carrier

wave generation function by timer. Set the contents of this

register through register A with the TV2A instruction.

(2) Precautions

Note the following for the use of timers.

• Count source

Stop timer 1 or timer 2 counting to change its count source.

• Watchdog timer

Be sure that the timing to execute the WRST instruction in

order to operate WDT efficiently.

• Writing to reload register R1

When writing data to reload register R1 while timer 1 is

operating, avoid a timing when timer 1 underflows.

• Timer 1 count operation

When the bit 5 of the watchdog timer (WDT) is selected as

the timer 1 count source, the error of maximum ± 256 µs

(at the minimum instruction execution time : 8 µs) is

generated from timer 1 start until timer 1 underflow. When

programming, be careful about this error.

• Stop of timer 2

Avoid a timing when timer 2 underflows to stop timer 2.

• Writing to reload register R2H

When writing data to reload register R2H while timer 2 is

operating, avoid a timing when timer underflows.

• Timer 2 carrier wave output function

When to expand “H” interval of carrier wave is valid, set “1”

or more to reload register R2H.

Rev.1.33 Mar 18, 2004 page 12 of 67

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