PIC16F636T-I/SL(2005) View Datasheet(PDF) - Microchip Technology

Part Name

Description

Manufacturer

PIC16F636T-I/SL
(Rev.:2005)

8/14-Pin Flash-Based, 8-Bit CMOS Microcontrollers with nanoWatt Technology

Microchip Technology 

PIC12F635/PIC16F636/639

2.2.2.2 Option Register

The Option register is a readable and writable register

which contains various control bits to configure:

• TMR0/WDT prescaler

• External RA2/INT interrupt

• TMR0

• Weak pull-up/pull-downs on PORTA

Note:

To achieve a 1:1 prescaler assignment for

TMR0, assign the prescaler to the WDT by

setting the PSA bit to ‘1’

(OPTION_REG<3>). See Section 5.4

“Prescaler”.

REGISTER 2-2:

OPTION_REG – OPTION REGISTER (ADDRESS: 81h)

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

RAPU INTEDG T0CS

T0SE

PSA

PS2

bit 7

R/W-1

PS1

R/W-1

PS0

bit 0

bit 7

bit 6

bit 5

bit 4

bit 3

bit 2-0

RAPU: PORTA Pull-up/Pull-down Enable bit

1 = PORTA pull-ups/pull-downs are disabled

0 = PORTA pull-ups/pull-downs are enabled by individual port latch values

INTEDG: Interrupt Edge Select bit

1 = Interrupt on rising edge of RA2/INT pin

0 = Interrupt on falling edge of RA2/INT pin

T0CS: TMR0 Clock Source Select bit

1 = Transition on RA2/T0CKI pin

0 = Internal instruction cycle clock (CLKOUT)

T0SE: TMR0 Source Edge Select bit

1 = Increment on high-to-low transition on RA2/T0CKI pin

0 = Increment on low-to-high transition on RA2/T0CKI pin

PSA: Prescaler Assignment bit

1 = Prescaler is assigned to the WDT

0 = Prescaler is assigned to the Timer0 module

PS<2:0>: Prescaler Rate Select bits

Bit Value TMR0 Rate WDT Rate

000

1:2

1:1

001

1:4

1:2

010

1:8

1:4

011

1 : 16

1:8

100

1 : 32

1 : 16

101

1 : 64

1 : 32

110

1 : 128 1 : 64

111

1 : 256 1 : 128

Legend:

R = Readable bit

- n = Value at POR

W = Writable bit

‘1’ = Bit is set

U = Unimplemented bit, read as ‘0’

‘0’ = Bit is cleared x = Bit is unknown

© 2005 Microchip Technology Inc.

Preliminary

DS41232B-page 21

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