NCT6627UD Nuvoton Technology Corporation of America, NCT6627UD Datasheet - Page 163

• Manufacturer Part Number: NCT6627UD
• Manufacturer: Nuvoton Technology Corporation of America

Specifications of NCT6627UD

• Lead Free Status / Rohs Status: Supplier Unconfirmed

W83627UHG/NCT6627UD
15. WATCHDOG TIMER
Pin 77 is the WDTO# pin in the W83627UHG.
The Watchdog Timer of the W83627UHG consists of an 8-bit programmable time-out counter and a control and
status register. The time-out counter ranges from 1 to 255 minutes in the minute mode, or 1 to 255 seconds in the
second mode. The units of Watchdog Timer counter are selected at Logical Device 8, CR[F5h], bit[3]. The time-
out value is set at Logical Device 8, CR[F6h]. Writing zero disables the Watchdog Timer function. Writing any
non-zero value to this register causes the counter to load this value into the Watchdog Timer counter and start
counting down.
The W83627UHG outputs a low signal to the WDTO# pin (pin 77) when a time-out event occurs. In other words,
when the value is counted down to zero, the timer stops, and the W83627UHG sets the WDTO# status bit in
Logical Device 8, CR[F7h], bit[4], outputting a low signal to the WDTO# pin(pin 77). Writing a zero will clear the
status bit and the WDTO# pin returns to high. Writing a zero will clear the status bit. This bit will also be cleared if
LRESET# or PWROK# signal is asserted.
Please note that the output type of WDTO# (pin 77) is open-drain.
Publication Release Date: October 26, 2010
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Revision 1.7