Datasheet

ManualsBrandsMICROCHIP TECHNOLOGY ManualsMicrocontrollers, Microprocessors & QuartzesEmbedded microcontroller SSOP 20 8-Bit 16 MHz I/O number 17

 2010-2013 Microchip Technology Inc. DS40001430E-page 21

PIC16(L)F720/721

2.2.2.2 OPTION_REG Register

The OPTION_REG register, shown in Register 2-2, is

a readable and writable register, which contains

various control bits to configure:

• Software programmable prescaler for the Timer0/

WDT

• External RA2/INT interrupt

•Timer0

• Weak pull-ups on PORTA or PORTB

Note: To achieve a 1:1 prescaler assignment for

Timer0, assign the prescaler to the WDT

by setting the PSA bit of the

OPTION_REG register to ‘1’. Refer to

Section 12.1.3 “Software

Programmable Prescaler”.

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

RABPU

INTEDG T0CS T0SE PSA PS2 PS1 PS0

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 RABPU

: PORTA or PORTB Pull-up Enable bit

1 = PORTA or PORTB pull-ups are disabled

0 = PORTA or PORTB pull-ups are enabled by individual bits in the WPUB register

bit 6 INTEDG: Interrupt Edge Select bit

1 = Interrupt on rising edge of INT pin

0 = Interrupt on falling edge of INT pin

bit 5 T0CS: Timer0 Clock Source Select bit

1 = Transition on T0CKI pin

0 = Internal instruction cycle clock (F

OSC/4)

bit 4 T0SE: Timer0 Source Edge Select bit

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

0 = Increment on low-to-high transition on 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 PS<2:0>: 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