M34280M1-254FP View Datasheet(PDF) - Mitsumi

Part Name

Description

Manufacturer

M34280M1-254FP

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

Mitsumi 

MITSUBISHI MICROCOMPUTERS

4280 Group

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

LIST OF PRECAUTIONS

ΠNoise and latch-up prevention

Connect a capacitor on the following condition to prevent noise

and latch-up;

• connect a bypass capacitor (approx. 0.01 µF) between pins

VDD and VSS at the shortest distance,

• equalize its wiring in width and length, and

• use the thickest wire.

In the One Time PROM version, port E2 is also used as VPP

pin. Connect this pin to VSS through the resistor about 5 kΩ

which is assigned to E2/VPP pin as close as possible at the

shortest distance.

 Notes on unused pins

(Note in order to set the output latch to “0” to make pins open)

• After system is released from reset, a port is in a high-

impedance state until the output latch of the port is set to

“0” by software.

Accordingly, the voltage level of pins is undefined and the

excess of the supply current may occur.

• To set the output latch periodically is recommended

because the value of output latch may change by noise or

a program run away (caused by noise).

(Note when connecting to VSS and VDD)

• Connect the unused pins to VSS and VDD at the shortest

distance and use the thick wire against noise.

Ž Timer

• Count source

Stop timer 1 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.

 Program counter

Make sure that the program counter does not specify after the

last page of the built-in ROM.

MITSUBISHI

ELECTRIC

21

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