4250 Просмотр технического описания (PDF) - MITSUBISHI ELECTRIC

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4250

SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER

MITSUBISHI ELECTRIC  

MITSUBISHI MICROCOMPUTERS

4250 Group

SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER

The 4250 Group timer consists of the following circuits.

• Prescaler : frequency divider

• Timer 1 : 8-bit programmable timer with the interrupt function

These timers can be controlled with the timer control register V1

and key-on wakeup control register K0.

Each function is described below.

Table 9 Function related timers

Circuit

Prescaler

Structure

Frequency divider

Count source

Instruction clock

Timer 1

8-bit programmable Prescaler output (ORCLK)

binary down counter

Frequency

dividing ratio

Use of output signal

4, 512

• Timer 1 count source

1 to 256

• TOUT pin

• Timer 1 interrupt

Control

register

V1

K0

V1

Prescaler

V12

K03

0

1/4

0

1

1/512 1

Instruction clock

Internal clock

generating circuit

(divided by 4)

XIN

V12(Note)

0

ORCLK

1

Bit 7

Timer 1 (8)

Timer 1 underflow

signal

T1F

Bit 0

Timer 1

interrupt

Timer 1 reload register R 1(8)

T1AB

instruction

Register B(4) Register A(4)

TAB1 instruction

TAB1

instruction

1/2

G1 output

V13

1

G1/ TOUT

0

G1 input

Note: Count source is stopped by clearing to “0.”

: Data is automatically set from a reload register

when timer 1 underflows (auto-reload function).

Fig. 19 Timers structure

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ELECTRIC

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