M34280M1-XXXGP View Datasheet(PDF) - Mitsumi

Part Name

Description

Manufacturer

M34280M1-XXXGP

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

(1) Internal state at reset

Table 6 shows port state at reset, and Figure 19 shows internal

state at reset (they are retained after system is released from

reset).

The contents of timers, registers, flags and RAM except shown

in Figure 19 are undefined, so set the initial value to them.

• Program counter (PC) .............................................................. 0 0 0 0 0 0 0 0 0 0

Address 0 in page 0 is set to program counter.

• Power down flag (P) ................................................................. 0

• Timer 1 underflow flag (T1F) ................................................... 0

• Timer control register V1 .......................................................... 0 0 0

• Carrier wave selection register C ............................................ 1 1 1

• Pull-down control register PU0 ................................................ 0 0 0

• Logic operation selection register LO ...................................... 0 0

• Most significant ROM code reference enable flag (URS)

0

• Carry flag (CY) ......................................................................... 0

• Register A ................................................................................. 1 1 1 1

• Register B ................................................................................. 1 1 1 1

• Stack pointer (SP) .................................................................... 1 1

Fig. 19 Internal state at reset

Table 6 Port state at reset

Name

State at reset

D0–D6

“H” output

D7

“H” output

G0–G3, E2

Input port (Pull-down transistor ON)

E0, E1

Input circuit OFF (Pull-down transistor OFF)

Note: The contents of all output latch is initialized to “0.”

State after system is released from reset

High impedance state

Input circuit OFF (Pull-down transistor OFF)

Input port (Pull-down transistor ON)

Input port (Pull-down transistor OFF)

VOLTAGE DROP DETECTION CIRCUIT

The built-in drop detection circuit is designed to detect a drop in

voltage at operating and to reset the microcomputer if the supply

voltage drops below the specified value (Typ. 1.50 V) or less.

The voltage drop detection circuit is stopped and power

dissipation is reduced at the RAM back-up mode, when the

functions except the RAM and pull-down control register (PU0)

are initialized.

VDD

Reset voltage

Internal reset signal

Microcomputer starts operation

after f(XIN) is counted to 16384 times.

Fig. 20 Voltage drop detection circuit operation waveform

MITSUBISHI

ELECTRIC

17

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