PIC16F882_09 Datasheet, PDF (32/328 Pages) Microchip Technology – 28/40/44-Pin, Enhanced Flash-Based 8-Bit CMOS Microcontrollers with nanoWatt Technology

PIC16F882/883/884/886/887
2.2.2.2 OPTION Register
The OPTION register, shown in Register 2-2, is a
readable and writable register, which contains various
control bits to configure:
• Timer0/WDT prescaler
• External INT interrupt
• Timer0
• Weak pull-ups on PORTB
Note:
To achieve a 1:1 prescaler assignment for
Timer0, assign the prescaler to the WDT by
setting PSA bit of the OPTION register to
‘1’. See Section 6.3 “Timer1 Prescaler”.
REGISTER 2-2: OPTION_REG: OPTION REGISTER
R/W-1
RBPU
bit 7
R/W-1
INTEDG
R/W-1
T0CS
R/W-1
T0SE
R/W-1
PSA
R/W-1
PS2
R/W-1
PS1
R/W-1
PS0
bit 0
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
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2-0
RBPU: PORTB Pull-up Enable bit
1 = PORTB pull-ups are disabled
0 = PORTB pull-ups are enabled by individual PORT latch values
INTEDG: Interrupt Edge Select bit
1 = Interrupt on rising edge of INT pin
0 = Interrupt on falling edge of INT pin
T0CS: Timer0 Clock Source Select bit
1 = Transition on T0CKI pin
0 = Internal instruction cycle clock (FOSC/4)
T0SE: Timer0 Source Edge Select bit
1 = Increment on high-to-low transition on T0CKI pin
0 = Increment on low-to-high transition on 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 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
DS41291F-page 30
© 2009 Microchip Technology Inc.