FDC37B78X SMSC Corporation, FDC37B78X Datasheet - Page 215

• Manufacturer Part Number: FDC37B78X
• Description: Enhanced Super I/O Controller with ACPI Support/ Real Time Clock and Consumer IR
• Manufacturer: SMSC Corporation

WDT_CTRL
Default = 0x00
Cleared by VTR
POR
NAME
REG INDEX
0xF4
Watch-dog timer Control
Bit[0] Watch-dog Status Bit, R/W
=1WD timeout occured
=0WD timer counting
Bit[1] Power LED Toggle Enable, R/W
=1Toggle Power LED at 1Hz rate with 50 percent
duty cycle. (1/2 sec. on, 1/2 sec. off)
=0Disable Power LED Toggle
Bit[2] Force Timeout, W
=1Forces WD timeout event; this bit is self-clearing
Bit[3] P20 Force Timeout Enable, R/W
= 1Allows rising edge of P20, from the Keyboard
Controller, to force the WD timeout event. A WD
timeout event may still be forced by setting the
Force Timeout Bit, bit 2.
= 0P20 activity does not generate the WD timeout
event.
Note: The P20 signal will remain high for a
minimum of 1us and can remain high indefinitely.
Therefore, when P20 forced timeouts are enabled,
a self-clearing edge-detect circuit is used to
generate a signal which is ORed with the signal
generated by the Force Timeout Bit.
Bit[4] Reserved. Set to 0.
Bit[5] Stop_Cnt: This is used to terminate Delay 2
(Note 1) without generating a power down. This is
used if the software determines that the power
down should be aborted. When read, this bit
indicates the following: Stop_Cnt = 0; Counter
running Stop_Cnt = 1; Counter Stopped. Note: The
write is self clearing.
Bit[6] Restart_Cnt: This is used to restart Delay 2
(Note 1) from the button input to the generation of
the power down. When restarted, the count will
start over and delay the power down for the time
that Delay 2 is set for (Default=500msec). The
software can continue to do this indefinately with
out allowing a powerdown. This bit is self clearing.
1=Restart; Automatically cleared.
Bit[7]
power down. This bit is self clearing.
Note 1: This delay is programmable via the Delay 2
Time Set Register at Logical Device 8, 0xB8.
SPOFF: This is used to force a software
215
DEFINITION
STATE
C