12C509 Просмотр технического описания (PDF) - Microchip Technology

Номер в каталоге

Компоненты Описание

производитель

12C509

8-Pin, 8-Bit CMOS Microcontrollers

Microchip Technology 

PIC12C5XX

4.4 OPTION Register

The OPTION register is a 8-bit wide, write-only

register which contains various control bits to

configure the Timer0/WDT prescaler and Timer0.

By executing the OPTION instruction, the contents of

the W register will be transferred to the OPTION

register. A RESET sets the OPTION<7:0> bits.

Note:

Note:

If TRIS bit is set to ‘0’, the wake-up on

change and pull-up functions are disabled

for that pin; i.e., note that TRIS overrides

OPTION control of GPPU and GPWU.

If the T0CS bit is set to ‘1’, GP2 is forced to

be an input even if TRIS GP2 = ‘0’.

FIGURE 4-5: OPTION REGISTER

W-1

W-1

W-1

W-1

W-1

W-1

W-1

GPWU GPPU T0CS T0SE

PSA

PS2

PS1

bit7

6

5

4

3

2

1

bit 7:

GPWU: Enable wake-up on pin change (GP0, GP1, GP3)

1 = Disabled

0 = Enabled

bit 6:

GPPU: Enable weak pull-ups (GP0, GP1, GP3)

1 = Disabled

0 = Enabled

bit 5:

T0CS: Timer0 clock source select bit

1 = Transition on T0CKI pin

0 = Transition on internal instruction cycle clock, Fosc/4

bit 4:

T0SE: Timer0 source edge select bit

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

0 = Increment on low to high transition on the T0CKI pin

bit 3:

PSA: Prescaler assignment bit

1 = Prescaler assigned to the WDT

0 = Prescaler assigned to Timer0

bit 2-0: PS2:PS0: Prescaler rate select bits

Bit Value Timer0 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

W-1

PS0

bit0

W = Writable bit

U = Unimplemented bit

- n = Value at POR reset

Reference Table 4-1 for

other resets.

© 1999 Microchip Technology Inc.

DS40139E-page 17

Share Link: