4250 Просмотр технического описания (PDF) - MITSUBISHI ELECTRIC

Номер в каталоге

Компоненты Описание

производитель

4250

SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER

MITSUBISHI ELECTRIC  

MITSUBISHI MICROCOMPUTERS

4250 Group

SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER

(5) Key-on wakeup control register K0

• Key-on wakeup control register K0

The interrupt valid waveform for INT pin/key-on wakeup

valid waveform selection bit, the ports G1–G3 key-on

wakeup control bit and the ports S0–S3 key-on wakeup

control bit are assigned to the register K0. Set the contents

of this register through register A with the TK0A instruction.

The TAK0 instruction can be used to transfer the contents

of register K0 to register A.

Table 14 Key-on wakeup control register

Key-on wakeup control register K0

K03 Prescaler dividing ratio selection bit

Interrupt valid waveform for INT pin/

K02 key-on wakeup valid waveform selection

bit (Note 2)

at reset : 00002

at RAM back-up : state retained

0 Instruction clock divided by 4

1 Instruction clock divided by 512

0 Rising waveform (“L” → “H”)

1 Falling waveform (“H” → “L”)

R/W

K01 Ports G1–G3 key-on wakeup control bit

0 Key-on wakeup not used

1 Key-on wakeup used (“L” level recognized)

K00 Ports S0–S3 key-on wakeup control bit

0 Key-on wakeup not used

1 Key-on wakeup used (“L” level recognized)

Notes 1: “R” represents read enabled, and “W” represents write enabled.

2: Set a value to the bit 2 of register K0, and execute the SNZ0 instruction to clear the EXF0 flag after executing at least one

instruction. According to the input state of G0/INT pin, the external interrupt request flag (EXF0) may be set when the

interrupt valid waveform is changed.

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 3584 to 3585 machine cycles for the time

required to stabilize the f(XIN) oscillation.

Fig. 24 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. 25 Set source and clear source of the P flag

Software start

P = “1” Yes

?

No

Cold start

Warm start

Fig. 26 Start condition identified example using the SNZP

instruction

MITSUBISHI

28

ELECTRIC

Share Link: