w681308 Winbond Electronics Corp America, w681308 Datasheet - Page 27

• Manufacturer Part Number: w681308
• Description: Usb Audio Controller
• Manufacturer: Winbond Electronics Corp America

WTRF is set to a 1 on a Watchdog timer reset, set to 0 on power on/down resets. WTRF is not altered by an external reset.
POR is set to 1 by a power-on reset. EWT is cleared to 0 on a Power-on reset and unaffected by other resets.
To prevent software from accidentally enabling or disabling the watch dog reset function, the bit of WDCON requires Time
Access (TA) procedure to write.
Example:
WD1, WD0 are Time-out bits for Watchdog Timer located at CKCON.7 and CKCON.6. These bits determine the time-out
period of the watchdog timer. The reset time-out period is 512 clocks longer than the watchdog time-out.
Control Bit
RWT
EWT
mov TA, #0AAH
mov TA, #055H
clr
WDIF
WD1
0
0
1
1
Enable Watchdog
Reset Watchdog
timer Reset
Name
Timer
Setting this bit will enable the Watchdog timer Reset function.
This bit helps in putting the watchdog timer into a know state. It also helps in
resetting the watchdog timer before a time-out occurs. Failing to set the EWT before
time-out will cause an interrupt, if EWDI (EIE.4) is set, and 512 clocks after that a
watchdog timer reset will be generated if EWT is set. This bit is self-clearing.
Table 9 Watchdog Timer Timeout Control
WD0
0
1
0
1
Table 8 Watchdog Control Bits
XXXX PRODUCT DESCRIPTION
27
Interrupt time-out
2
2
2
2
23
25
26
28
Function
Reset time-out
2
2
2
2
23
25
26
28
W681308
Rev1.2
+ 512
+ 512
+ 512
+ 512