sh6620a SinoWealth Micro-Electronics Corp. Ltd, sh6620a Datasheet - Page 7

• Manufacturer Part Number: sh6620a
• 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. Thus, the WDT will always run even in the STOP
mode. SH6620A generates a RESET condition when the watchdog times-out. The watchdog can be enabled or disabled
permanently by user option. To prevent it timing out and generating a device RESET condition, you can write this bit as "1"
before timing-out. The WDT has a time-out period of more than 7ms (V
per-scaler with a division ratio of up to 1:2048 can be assigned to the WDT under the software control by writing to the TM0
register.
Pre-scaler divide ratio (valid for V
Address
TM0.2
$1E
1
1
1
1
0
0
0
0
TM0.1
WDT
Bit3
1
1
0
0
1
1
0
0
RC OSC
TM0.0
Bit2
0.875ms
1
0
1
0
1
0
1
0
-
DD
T0
= 5V):
OSC/4
T0E
SCALER_1
Internal
Bit1
-
/8
Pre-scaler divide ratio
EOR
1:2048 (Power on initial)
WDT Time
out Period
WDT & WARM-UP
0
1
WDT TIMEOUT
7ms
Bit0
OSCILLATOR
BUILT-IN RC
-
COUNTER
1:128
1:512
1:32
/1
M
U
X
1:1
1:2
1:4
1:8
T0S
7
/2
R/W
/4 /8
W
PRESCALER TM0
Final WDT
Time OUT
period
DD
W D T
3
= 5V). If longer time-out periods are needed, a
/32 /128 /512 /2048
Bit3: WDT time-out bit (write one only)
TIMER0 (8BITS)
TM0 [2:0]
3
Timer-out period
Remarks
14,336ms
3,584ms
224ms
896ms
14ms
28ms
56ms
7ms
SH6620A