sh6622a SinoWealth Micro-Electronics Corp. Ltd, sh6622a Datasheet - Page 7

• Manufacturer Part Number: sh6622a
• Description: Mask 4-bit Microcontroller
• Manufacturer: SinoWealth Micro-Electronics Corp. Ltd

System Register $1E
The input clock of watchdog timer is generated by a built-in RC oscillator. So that the WDT will always run even in the STOP
mode. SH6622A generates a RESET condition when watchdog is time-out. Watchdog can be enabled or disabled permanently
by user option. To prevent it from time-out and generating a device RESET condition, you should write this bit as "1" before
timing-out. The WDT has a time-out period of more than 7ms (V
a divide ratio of up to 1:2048 can be assigned to the WDT under software controlled by writing to the TM0 register.
Prescaler divide ratio (valid for V
Address
TM0.2
$1E
1
1
1
1
0
0
0
0
WDT
Bit3
TM0.1
0
1
1
0
0
1
1
0
RC OSC
TM0.0
Bit2
-
0
0.875ms
1
0
1
0
1
0
1
( USER OPTION )
DD
WDT ENABLE
= 5V):
TOE
INTERNAL
SCALER_1
T0
Bit1
-
1:2048 (Power on initial)
/8
Prescaler divide ratio
EOR
OSC/4
WDT TIME
OUT PERIOD
WDT & WARM
BUILT-IN RC
OSCILLATOR
UP COUNTER
WDT TIMEOUT
1:128
1:512
Bit0
1:32
7ms
1:1
1:2
1:4
1:8
-
/1
0
1
T0S
M
U
X
DD
7
/2
= 5V). If longer time-out periods are desired, a prescaler with
R/W
W
/4 /8
PRESCALER TM0
FINAL WDT
TIME OUT
PERIOD
W D T
TIMER0 (8 BITS)
TM0 [2:0]
3
/32 /128 /512 /2048
Bit3:WDT time-out bit (write one only)
3
Timer-out period
14,336ms
Remark
3,584ms
224ms
896ms
14ms
28ms
56ms
7ms
SH6622A