M34280E1FP View Datasheet(PDF) - MITSUBISHI ELECTRIC

Part Name

Description

Manufacturer

M34280E1FP

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

MITSUBISHI ELECTRIC  

MITSUBISHI MICROCOMPUTERS

4280 Group

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

(4) Return signal

An external wakeup signal is used to return from the RAM

back-up mode. Table 8 shows the return condition for each

return source.

Table 8 Return source and return condition

Return source

Return condition

Remarks

Ports D7, E0, E1

Return by an external “H” level Only key-on wakeup function of the port whose pull-down transistor is

input.

turned ON is valid.

Ports G, E2

Return by an external “H” level Key-on wakeup function is always valid.

input.

(5) Pull-down control register PU0

• Pull-down control register PU0

Register PU0 controls the ON/OFF of pull-down transistor,

input, key-on wakeup function of ports E0, E1 and D7.

Set the contents of this register through register A with the

TPU0A instruction.

Table 9 Pull-down control register

Pull-down control register PU0

PU02 Port D7 pull-down control bit

PU01 Port E1 pull-down control bit

PU00 Port E0 pull-down control bit

Note: “W” represents write enabled.

at reset : 0002

at RAM back-up : state retained

W

0 Pull-down transistor OFF, input circuit OFF, key-on wakeup invalid

1 Pull-down transistor ON, input circuit ON, key-on wakeup valid

0 Pull-down transistor OFF, key-on wakeup invalid

1 Pull-down transistor ON, key-on wakeup valid

0 Pull-down transistor OFF, key-on wakeup invalid

1 Pull-down transistor ON, key-on wakeup valid

Reset

(Stabilizing time a )

A

POF instruction

is executed

f(XIN) oscillation

Return input

(Stabilizing time a )

B

f(XIN) stop

(RAM back-up

mode)

Stabilizing time a : Microcomputer starts its operation after f(XIN) is counted to16384 times.

Fig. 21 State transition

POF instruction

Power down flag P

SQ

Reset input

R

q Set source

q Clear source

POF instruction is executed

Reset input

Fig. 22 Set source and clear source of the P flag

Software start

P = “1”

Yes

?

No

Cold start

Warm start

Fig. 23 Start condition identified example using the SNZP

instruction

MITSUBISHI

ELECTRIC

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