SM79164 Datasheet, PDF (12/25 Pages) SyncMOS Technologies,Inc – 8 - Bit Micro-controller with 64KB flash & 4KB RAM embedded

SyncMOS Technologies International. Inc.
SM79164
3.1 Watch Dog Timer Registers:
Watch Dog Timer Registers - WDT Control Register (WDTC, $9F)
bit-7
bit-0
WDTE Reserve CLEAR Unused Unused
PS2
PS1
PS0
Read / Write: R/W
-
R/W
-
-
R/W
R/W
R/W
Reset value:
0
*
0
*
*
0
0
0
WDTE : Watch Dog Timer enable bit
CLEAR : Watch Dog Timer reset bit
PS[2:0] : Overflow period select bits
PS [2:0]
000
001
010
011
100
101
110
111
Overflow Period (ms)
2.048
4.096
8.192
16.384
32.768
65.536
131.072
262.144
Watch Dog Key Register - (WDTKEY, $97H)
Read / Write:
Reset value:
bit-7
WDT
KEY7
W
0
WDT
KEY6
W
0
WDT
KEY5
W
0
WDT
KEY4
W
0
WDT
KEY3
W
0
WDT
KEY2
W
0
WDT
KEY1
W
0
bit-0
WDT
KEY0
W
0
By default, the WDTC is read only. User need to write values 1EH, E1H sequentially to the WDTKEY($97H) register to
enable the WDTC write attribute, That is
MOV WDTKEY, # 1EH
MOV WDTKEY, # E1H
When WDTC is set, user need to write another values E1H, 1EH sequentially to the WDTKEY($97H) register to disable the
WDTC write attribute, That is
MOV WDTKEY, # E1H
MOV WDTKEY, # 1EH
Specifications subject to change without notice,contact your sales representatives for the most recent information.
12/26
Ver 2.1 SM79164 08/2006