4280 datasheet(21/48 Pages) RENESAS

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MITSUBISHI MICROCOMPUTERS

4280 Group

SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER for INFRARED REMOTE CONTROL TRANSMITTERS

Fig. 24 Clock control circuit structure

Clock signal f(XIN) is obtained by externally connecting a ceramic

resonator. Connect this external circuit to pins XIN and XOUT at

the shortest distance as shown Figure 26.

A feedback resistor is built-in between XIN pin and XOUT pin.

ROM ORDERING METHOD

Please submit the information described below when ordering

Mask ROM.

(1) Mask ROM Order Confirmation Form................................. 1

(2) Data to be written into mask ROM .......................... EPROM

(three sets containing the identical data)

(3) Mark Specification Form .................................................... 1

Fig. 25 Ceramic resonator external circuit

CLOCK CONTROL

The clock control circuit consists of the following circuits.

• System clock generating circuit

• Control circuit to stop the clock oscillation

• Control circuit to return from the RAM back-up state

OSC

POF instruction

XIN

XOUT

CCK instruction

STCK

INSTCK

Frequency

divider

(divided by 8)

Multi-

plexer

Internal clock

generating circuit

(divided by 4)

Internal power-on reset circuit

Pull-down control

Port D7

Ports E0, E1

Ports E2, G0–G3

4280

XIN

XOUT

CIN

COUT

Use the resonator

manufacturer’s

recommended value

because constants

such as capacitance

depend on the

resonator.

4280 Datasheet(PDF) 21 Page - Renesas Technology Corp

4280 Datasheet(HTML) 21 Page - Renesas Technology Corp

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