Datasheet

PIC16HV540
DS40197B-page 40 Preliminary  2000 Microchip Technology Inc.
voltage may approach the maximum value. Again this
condition should be considered when interfacing to
external circuitry.
In addition, the voltage level applied to the external V
DD
pin and operational temperature affects the internal
regulation voltage.
FIGURE 7-12: WATCHDOG TIMER BLOCK DIAGRAM
TABLE 7-6: SUMMARY OF REGISTERS ASSOCIATED WITH THE WATCHDOG TIMER
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Value on
Power-On
Reset
Value on
MCLR and
WDT Reset
Value on
Wake-up
on Pin
Change
Value on
Brown-out
Reset
N/A OPTION
— — T0CS T0SE PSA PS2 PS1 PS0 --11 1111 --11 1111 --11 1111 --11 1111
N/A OPTION2
— — PCWU SWDTEN RL SL BODL BODEN --UU UUU --uu uuuu --uu uuuu --xx xxxx
Legend: Shaded boxes = Not used by Watchdog Timer, — = unimplemented, read as '0', u = unchanged, x = unknown.
Postscaler
Watchdog
Timer
WDTEN
Configuration
bit
SWDTEN bit
From TMR0 Clock Source
M
U
X
0
1
PSA
Postscaler
8 - to - 1 MUX
PS<2:0>
To T M R0
1
PSA
MUX
0
WDT
Time-out
Note: T0CS, T0SE, PSA, PS<2:0>
are bits in the OPTION register.