18

* This specification are subject to be changed without notice.

7.20.1999

EM73201

4-BIT MICRO-CONTROLLER FOR GENERAL PURPOSE PRODUCT

Preliminary

Infrared signal command port

PORT4

PORT5

Frequecy divider

Duty controller

fc

P1.0/CLKOUT

fc

fc/8

fc/16

fc/64

fc/16 , 1/4 duty

fc/16 , 1/2 duty

fc/16 , 3/4 duty

Program example:

To disable CLKOUT before sleep.

To enable a CLKOUT signal with frequency

LDIA #0000B;

fc/16, 3/4 duty .

OUTA P5;

LDIA #0000B;

OUTA P4; set clkout pin in high state

OUTA P5;

LDIA #0100B;

LDIA #1111B;

OUTA P16; Sleep

OUTA P4;

::

WATCH-DOG-TIMER

Watch-dog-timer (WDT) can help user to detect the malfunction (runaway) of CPU and give system a time

up signal every certain time. User can use the time up signal to give system a reset signal when system is fail.

The watch-dog-timer is enabled or disabed by mask option. If the mask option of WDT is enabled and the

CPU is reseted or waked up, the WDT will be cleared and counting. When the CPU is sleeping, the WDT

will be disabled.

The basic structure of watch-dog-timer control is composed by a 4-stage binary counter and a control unit.

The WDT counter counts for a certain time to check the CPU status, if there is no malfunction happened, the

counter will be cleared and counting. Otherwise, if there is a malfunction happened, the WDT control will

send a signal (low active) to reset CPU. The WDT checking period is assign by P21 (WDT command port).

E

A

B

C

D

CLK OUT

X0

X

X

X

HIGH

1

1

X

X

X

fc/12

0

1

0

0

0

fc/8

0

1

0

0

1

fc/16

0

1

0

1

0

fc/32

0

1

0

1

1

fc/64

0

1

1

0

0

LOW

0

1

1

0

1

fc/16 ; 1/4 duty

0

1

1

1

0

fc/16 ; 1/2 duty

0

1

1

1

1

fc/16 ; 3/4 duty