
GMS81508/16
19
BASIC INTERVAL TIMER DATA REGISTER
2.5. WATCH DOG TIMER
The Watch Dog Timer is a means of recovery from a system problem.
In this Device, the Watch Dog Timer consists of 6-bit binary counter, 6-bit comparator and watch
dog timer register(WDTR). The source clock of WDT is overflow of Basic Interval Timer. The
interrupt request of WDT is generated when the counting value of WDT equal to the contents of
WDTR( bit0~5). This can be used as s/w interrupt or MICOM RESET signal(Watch Dog Function).
2.5.1. Control of Watch Dog Timer
It can be used as 6-bit timer or WDT according to bit5(WDTON) of Clock Control Register
(CKCTLR). The counter can be cleared by setting WDTCL ( Bit 6 of WDTR) and the WDTCL is
auto-cleared after 1 machine cycle. The initial state (after Reset) of WDTCL is
“
0
”
.
CLOCK CONTROL REGISTER
WATCH DOG TIMER REGISTER
WDT ON
0 : 6-bit Timer
1 : Watch Dog Timer
7
6
5
4
ENPCK
WDTON
3
BTCL
2
BTS2
1
BTS1
0
BTS0
W
W
W
W
W
W
<00D3
H
>
CKCTLR
Watch Dog Timer Clear
0 : free run
1 : W.D.T counter clear
7
6
WDTCL
5
WDTR5
4
3
2
1
0
W
W
W
W
W
W
W
W
<00E0
H
>
WDTR
Determines the interval of W.D.T Interrupt
WDTR3
WDTR4
WDTR0
WDTR1
WDTR2
B.I.T data
7
6
5
4
3
2
1
0
R
R
R
R
R
R
R
R
<00D3
H
>
BITR