Datasheet

ManualsBrandsMICROCHIP TECHNOLOGY ManualsMicrocontrollers, Microprocessors & QuartzesEmbedded microcontroller SOIC 18 8-Bit 4 MHz I/O number 13

PIC16C71X

DS30272A-page 18  1997 Microchip Technology Inc.

4.2.2.2 OPTION REGISTER

The OPTION register is a readable and writable regis-

ter which contains various control bits to conﬁgure the

TMR0/WDT prescaler, the External INT Interrupt,

TMR0, and the weak pull-ups on PORTB.

Applicable Devices 710 71 711 715

Note: To achieve a 1:1 prescaler assignment for

the TMR0 register, assign the prescaler to

the Watchdog Timer by setting bit PSA

(OPTION<3>).

FIGURE 4-8: OPTION REGISTER (ADDRESS 81h, 181h)

R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1

RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 R = Readable bit

W = Writable bit

U = Unimplemented bit,

read as ‘0’

- n = Value at POR reset

bit7 bit0

bit 7: RBPU: PORTB Pull-up Enable bit

1 = PORTB pull-ups are disabled

0 = PORTB pull-ups are enabled by individual port latch values

bit 6: INTEDG: Interrupt Edge Select bit

1 = Interrupt on rising edge of RB0/INT pin

0 = Interrupt on falling edge of RB0/INT pin

bit 5: T0CS: TMR0 Clock Source Select bit

1 = Transition on RA4/T0CKI pin

0 = Internal instruction cycle clock (CLKOUT)

bit 4: T0SE: TMR0 Source Edge Select bit

1 = Increment on high-to-low transition on RA4/T0CKI pin

0 = Increment on low-to-high transition on RA4/T0CKI pin

bit 3: PSA: Prescaler Assignment bit

1 = Prescaler is assigned to the WDT

0 = Prescaler is assigned to the Timer0 module

bit 2-0: PS2:PS0: Prescaler Rate Select bits

000

001

010

011

100

101

110

111

1 : 2

1 : 4

1 : 8

1 : 16

1 : 32

1 : 64

1 : 128

1 : 256

1 : 1