PIC16C712-04SLASHJW datasheet(63/108 Pages) MICROCHIP

63 / 108 page

Preliminary

DS41106A-page 63

PIC16C712/716

9.12

Watchdog Timer (WDT)

The Watchdog Timer is as a free running, on-chip, RC

oscillator which does not require any external compo-

nents. This RC oscillator is separate from the RC oscil-

lator of the OSC1/CLKIN pin. That means that the WDT

will run, even if the clock on the OSC1/CLKIN and

OSC2/CLKOUT pins of the device have been stopped,

for example, by execution of a SLEEP instruction.

During normal operation, a WDT time-out generates a

device RESET (Watchdog Timer Reset). If the device is

in SLEEP mode, a WDT time-out causes the device to

wake-up and continue with normal operation (Watch-

dog Timer Wake-up). The TO bit in the STATUS register

will be cleared upon a Watchdog Timer time-out.

The WDT can be permanently disabled by clearing

configuration bit WDTE (Section 9.1).

WDT time-out period values may be found in the Elec-

trical Specifications section under TWDT (parameter

#31). Values for the WDT prescaler (actually a

postscaler, but shared with the Timer0 prescaler) may

be assigned using the OPTION_REG register.

Note:

The CLRWDT and SLEEP instructions clear

the WDT and the postscaler, if assigned to

the WDT, and prevent it from timing out and

generating a device RESET condition.

Note:

When a CLRWDT instruction is executed

and the prescaler is assigned to the WDT,

the prescaler count will be cleared, but the

prescaler assignment is not changed.

FIGURE 9-15: WATCHDOG TIMER BLOCK DIAGRAM

FIGURE 9-16: SUMMARY OF WATCHDOG TIMER REGISTERS

Address Name

Bits 13:8

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

2007h

Config. bits

(1)

—

BODEN(1)

CP1

CP0

PWRTE(1)

WDTE

FOSC1

FOSC0

81h

OPTION_REG

N/A

RBPU

INTEDG

T0CS T0SE

PSA

PS2

PS1

PS0

Legend: Shaded cells are not used by the Watchdog Timer.

Note 1: See Figure 9-1 for operation of these bits.

From TMR0 Clock Source

(Figure 4-2)

To TMR0 (Figure 4-2)

Postscaler

WDT Timer

WDT

Enable Bit

PSA

8 - to - 1 MUX

PS2:PS0

MUX

PSA

WDT

Time-out

Note: PSA and PS2:PS0 are bits in the OPTION_REG register.

PIC16C712-04/JW Folha de dados(PDF) 63 Page - Microchip Technology

PIC16C712-04/JW Folha de dados(HTML) 63 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Folha de dados Download

Ligação URL