Datasheet

ManualsBrandsMICROCHIP TECHNOLOGY ManualsMicrocontrollers, Microprocessors & QuartzesEmbedded microcontroller SOIC 14 8-Bit 20 MHz I/O number 11

PIC12F508/509/16F505

4.5 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 regis-

ter. A Reset sets the OPTION<7:0> bits.

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

/RBPU and

GPWU

/RBWU).

Note: If the T0CS bit is set to ‘1’, it will override

the TRIS function on the T0CKI pin.

W-1 W-1 W-1 W-1 W-1 W-1 W-1 W-1

GPWU

GPPU T0CS T0SE PSA PS2 PS1 PS0

bit 7 bit 0

bit 7 GPWU

: Enable Wake-up on Pin Change bit (GP0, GP1, GP3)

1 = Disabled

0 = Enabled

bit 6 GPPU

: Enable Weak Pull-ups bit (GP0, GP1, GP3)

1 = Disabled

0 = Enabled

bit 5 T0CS: Timer0 Clock Source Select bit

1 = Transition on T0CKI pin (overrides TRIS on the 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 PS<2:0>: Prescaler Rate Select bits

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

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