CHAPTER 4 SETTING METHODS
[Example 1]
Using the system clock (f
X
) as the watchdog timer operation clock, setting the overflow time to
maximum cycle (2
20
/f
X
) (same content as the sample program setting)
WDTM
0 1 1 1 1
MOV WDTM, #01101111B
WDTM = 0b01101111;
The WDTM setting value is “011
01111
(bits 7, 6, and 5 must be set to 0, 1, and 1, respectively)”.
•
Assembly language
•
C language
Option byte (address: 0080H)
The option byte setting value is “1xx1xxx
0
(x: don’t care, bits 7 and 4 must be set to 1)”.
When the software is described together with the protect byte setting, the following results. (In the
example below, bits 6, 5, and 1 are set to 0, and bits 3 and 2 are set to 1.)
0 1 1
Operation clock selection
0 1
System
clock
(f
X
)
Overflow time setting
1 1 1
2
20
/f
X
1 x x x
0
1 x x
Oscillation control of the low-speed internal oscillator
0
Can be stopped by using software
OPBT CSEG
AT
0080H
DB
10011100B
DB
11111111B
Application Note U18847EJ1V0AN
14
