M34282M1-XXXGP View Datasheet(PDF) - MITSUBISHI ELECTRIC

Part Name

Description

Manufacturer

M34282M1-XXXGP

SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER

MITSUBISHI ELECTRIC  

MITSUBISHI MICROCOMPUTERS

4282 Group

SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER

(1) Internal state at reset

Table 6 shows port state at reset, and Figure 20 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 20 are undefined, so set the initial value to them.

• Program counter (PC) .............................................................. 0 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 2 underflow flag (T2F) ................................................... 0

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

• Timer control register V2 .......................................................... 0 0 0 0

• Port CARR output flag (CAR) .................................................. 0

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

• Pull-down control register PU1 ................................................ 0 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

• Register X ................................................................................. 0 0

• Register Y ................................................................................. 0 0 0 0

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

Fig. 20 Internal state at reset

Table 6 Port state at reset

Name

State at reset

D0–D3 High impedance state

D4–D7 High impedance state (Pull-down transistor OFF)

G0–G3 High impedance state (Pull-down transistor OFF)

E0, E1 High impedance state (Pull-down transistor OFF)

CARR “L” output

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

VOLTAGE DROP DETECTION CIRCUIT

The built-in voltage 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 in the RAM back-up mode with the

initialized CPU stopped.

VDD

Reset voltage

TYP 1.5V

(Note)

Internal reset signal

Microcomputer starts operation

after f(XIN) is counted to 16384 times.

Note: The voltage drop detection circuit does not have

the hysteresis characteristics in the detected voltage.

Fig. 21 Voltage drop detection circuit operation waveform

MITSUBISHI

18

ELECTRIC

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