EM73201
4-BIT MICRO-CONTROLLER FOR GENERAL PURPOSE PRODUCT
Infrared signal command port
PORT4
PORT5
Frequecy divider
Duty controller
fc
P1.0/CLKOUT
E
X
1
0
0
0
0
0
0
0
0
A
0
1
1
1
1
1
1
1
1
1
B
X
X
0
C
X
X
0
D
X
X
0
CLK OUT
HIGH
fc/12
fc/8
fc/16
0
0
1
0
1
0
fc/32
fc/64
LOW
0
1
1
1
0
0
1
0
1
fc/16 ; 1/4 duty
fc/16 ; 1/2 duty
fc/16 ; 3/4 duty
1
1
0
1
1
1
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;
OUTA P5;
fc/16, 3/4 duty .
LDIA #0000B;
OUTA P5;
LDIA #1111B;
OUTA P4;
:
OUTA P4; set clkout pin in high state
LDIA #0100B;
OUTA P16; Sleep
:
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).
* This specification are subject to be changed without notice.
7.20.1999 18
ELAN [ ELAN MICROELECTRONICS CORP ]
