S-19400 Datasheet, PDF (20/36 Pages) Seiko Instruments Inc – Watchdog operation voltage range

FOR AUTOMOTIVE 125°C OPERATION LOW CURRENT CONSUMPTION WATCHDOG TIMER WITH RESET FUNCTION
S-19400/19401 Series
Rev.2.1_00
6. Watchdog double pulse detection
If an edge is input to the WDI pin again within a specific period of time (the discharge time due to an edge detection +
1 charge-di_{_}s_{__}c_{_}h_{__}a_{__}rge time (t_WDL)) after inputting an edge to the WDI pin when the S-19400/19401 Series is the window
mode, the WDO pin output changes from "H" to "L".
When the watchdog timer_{___}b_{__}e_{_}c_{__}omes Disable due to a change of the WEN pin ("H" → "L" → "H") after inputting an
edge to the WDI pin, the WDO pin continues outputting "H" even if an edge is input to the WDI pin within the specific
period of time mentioned above.
6. 1 Double pulse detection due to rising edge detection
(S-1940xAxxA, S-1940xDxxA, S-1940xGxxA, S-1940xJxxA)
tWDL
VDD
CPOR
CWDT
1234
1 234
1 234
1 2 3 4 5 6 7 8 9 10
WDI
W / T "L"
(S-19400 only)
WEN
(Active "H")
WDO
RST
(S-19401 only)
Figure 34
6. 2 Double pulse detection due to falling edge detection
(S-1940xBxxA, S-1940xExxA, S-1940xHxxA, S-1940xKxxA)
VDD
CPOR
CWDT
WDI
W / T "L"
(S-19400 only)
WEN
(Active "H")
WDO
1234
1 234
1 234
1 2 3 4 5 6 7 8 9 10
Counter reset at the 1st edge
Output "H" → "L" at the 2nd edge
RST
(S-19401 only)
20
Figure 35