Datasheet

© 2005 Microchip Technology Inc. Preliminary DS41236B-page 23
PIC12F508/509/16F505
REGISTER 4-4: OPTION REGISTER (PIC16F505)
W-1 W-1 W-1 W-1 W-1 W-1 W-1 W-1
RBWU
RBPU T0CS T0SE PSA PS2 PS1 PS0
bit 7 bit 0
bit 7 RBWU
: Enable Wake-up on Pin Change bit (RB0, RB1, RB3, RB4)
1 = Disabled
0 = Enabled
bit 6 RBPU
: Enable Weak Pull-ups bit (RB0, RB1, RB3, RB4)
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
1 : 2
1 : 4
1 : 8
1 : 16
1 : 32
1 : 64
1 : 128
Bit Value Timer0 Rate WDT Rate