Datasheet

 2006-2012 Microchip Technology Inc. DS41291G-page 79
PIC16F882/883/884/886/887
REGISTER DEFINITIONS: OPTION REGISTER
REGISTER 5-1: OPTION_REG: OPTION REGISTER
R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1
RBPU
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 RBPU
: PORTB Pull-up Enable bit
1 = PORTB pull-ups are disabled
0 = PORTB pull-ups are enabled by individual PORT latch values
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: TMR0 Clock Source Select bit
1 = Transition on T0CKI pin
0 = Internal instruction cycle clock (F
OSC/4)
bit 4 T0SE: TMR0 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
Note 1: A dedicated 16-bit WDT postscaler is available. See Section 14.5 “Watchdog Timer (WDT)” for more
information.
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 TMR0 RATE WDT RATE
TABLE 5-1: SUMMARY OF REGISTERS ASSOCIATED WITH TIMER0
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Register
on Page
TMR0 Timer0 Module Register 77
INTCON GIE PEIE T0IE
INTE RBIE T0IF INTF RBIF 33
OPTION_REG
RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 79
TRISA TRISA7 TRISA6 TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 41
Legend: – = Unimplemented locations, read as ‘0’, u = unchanged, x = unknown. Shaded cells are not used by the
Timer0 module.