HD404328 View Datasheet(PDF) - Renesas Electronics

Part Name

Description

Manufacturer

HD404328

4-bit HMCS400-series microcomputer

Renesas Electronics 

HD404328 Series

Reset

The MCU is reset by inputting a high-level voltage to the RESET pin. At power-on or when stop mode is

cancelled, RESET must be high for at least one tRC to enable the oscillator to stabilize. During operation,

RESET must be high for at least two instruction cycles.

Initial values after MCU reset are shown in table 1.

Table 1 Initial Values After MCU Reset

Item

Program counter

Abbr.

(PC)

Initial Value

$0000

Status flag

Stack pointer

Interrupt

flags/mask

I/O

Interrupt enable flag

(ST)

(SP)

(IE)

Interrupt request flag (IF)

Interrupt mask

(IM)

Port data register (PDR)

Data control register (DCR)

1

$3FF

0

0

1

All bits 1

All bits 0

Port mode register A (PMRA) 0000

Port mode register B (PMRB) - - 00

Port mode register C (PMRC) 0000

Interrupt mode

register

Timer/

Timer mode

counters, serial register A

interface

Timer mode

register B

Timer mode

register C

Serial mode register

(IMR)

(TMA)

(TMB)

(TMC)

(SMR)

0000

0000

0000

0000

0000

Prescaler S

Prescaler W

Timer counter A

Timer counter B

(TCA)

(TCB)

$000

$00

$00

$00

Contents

Indicates program execution point from

start address of ROM area

Enables conditional branching

Stack level 0

Inhibits all interrupts

Indicates there is no interrupt request

Prevents (masks) interrupt requests

Enables output at level 1

Turns output buffer off (to high

impedance)

Refer to description of port mode register

A

Refer to description of port mode register

B

Refer to description of port mode register

C

Refer to description of interrupt mode

register

Refer to description of timer mode

register A

Refer to description of timer mode

register B

Refer to description of timer mode

register C

Refer to description of serial mode

register

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