S-19400 Datasheet, PDF (17/36 Pages) Seiko Instruments Inc – Watchdog operation voltage range

FOR AUTOMOTIVE 125°C OPERATION LOW CURRENT CONSUMPTION WATCHDOG TIMER WITH RESET FUNCTION
Rev.2.1_00
S-19400/19401 Series
3. Watchdog time-out detection
The watch_{__}d_{__}o_{__}g_{__}timer detects a time-out after the charge-discharge operation to the CWDT pin is performed 32 times,
then the WDO pin output changes from "H" to "L".
VDD
CPOR
CWDT
"L"
WDI
12 34
12345
12 34
29 30 31 32
12 3
WEN
(Active "H")
WDO
RST
(S-19401 only)
tWDU
tRST
Figure 28
4. Internal counter reset due to edge detection
When the WDI pin detects an edge during the charge-discharge operation to the CWDT pin, the internal counter
which counts the number of times of the charge-discharge operation is reset. The CWDT pin initiates the discharge
operation when an edge is detected, and initiates the charge-discharge operation again after the discharge operation
is completed.
4. 1 Counter reset due to rising edge detection
(S-1940xAxxA, S-1940xDxxA, S-1940xGxxA, S-1940xJxxA)
VDD
CPOR
CWDT
WDI
WEN
(Active "H")
WDO
RST
(S-19401 only)
1 234
1234 1 234
1234
30 31 32
1
Counter reset due to rising edge detection
Time-out after counter reset
Figure 29
17