W83627EG Nuvoton Technology Corporation of America, W83627EG Datasheet - Page 201

• Manufacturer Part Number: W83627EG
• Description: IC I/O CONTROLLER 128-QFP
• Manufacturer: Nuvoton Technology Corporation of America

Specifications of W83627EG

• Applications: PC's, PDA's
• Interface: LPC
• Voltage - Supply: 3.3V
• Package / Case: 128-XFQFN
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

W83627EHF/EF, W83627EHG/EG
14. WATCHDOG TIMER
The WDTO# pin is a multi-function pin with GP50 functions and is configured to the WDTO# function, if
Configuration Register CR[2Dh], bit 0 is set to zero.
The Watchdog Timer of the W83627EHF/EHG/EF/EG 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 W83627EHF/EHG/EF/EG 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
W83627EHF/EHG/EF/EG 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.
Additionally, GP40 (pin 85), GP42 (pin 83), GP44 (pin 81) and GP46 (pin 79) provides an alternative
WDTO# function. This function can be configured by the relative GPIO control register.
Please note that the output type of WDTO# (pin 77) and GP42 (pin 83) is push-pull and that of GP40
(pin 85), GP44 (pin 81) and GP46 (pin 79) is open-drain.
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