M34282E2GP View Datasheet(PDF) - Renesas Electronics

Part Name

Description

Manufacturer

M34282E2GP

SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER

Renesas Electronics 

4282 Group

TIMERS

The 4282 Group has the programmable timer.

• Programmable timer

The programmable timer has a reload register and enables

the frequency dividing ratio to be set. It is decremented from a

setting value n. When it underflows (count to n + 1), a timer 1

underflow flag is set to “1,” new data is loaded from the reload

register, and count continues (auto-reload function).

FF16

n: Counter initial value

Count starts

Reload

n

1st underflow

Reload

2nd underflow

0016

Timer 1 underflow flag “1”

“0”

n+1 count

n+1 count

Time

A skip instruction is executed

Fig. 12 Auto-reload function

The 4282 Group timer consists of the following circuit.

• Timer 1 : 8-bit programmable timer

• Timer 2 : 8-bit programmable timer

These timers can be controlled with the timer control registers

V1 and V2.

Each timer function is described below.

Table 3 Function related timer

Circuit

Structure

Count source

Frequency

dividing ratio

Use of output signal

Timer 1

8-bit programmable • Carrier wave output (CARRY) 1 to 256

• Carrier wave output control

binary down counter • Bit 5 of watchdog timer

Timer 2

8-bit programmable • f(XIN)

1 to 256

• Carrier wave output

binary down counter • f(XIN)/2

14-bit timer

14-bit fixed frequency • Instruction clock

16384

• Watchdog timer

• Timer 1 count source

Control

register

V1

V2

Rev.1.33 Mar 18, 2004 page 10 of 67

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