PIC16F62X
4.2.2.2
OPTION REGISTER
Note: To achieve a 1:1 prescaler assignment for
TMR0, assign the prescaler to the WDT
(PSA = 1). See Section 6.3.1
The OPTION register is a readable and writable
register which contains various control bits to configure
the TMR0/WDT prescaler, the external RB0/INT
interrupt, TMR0, and the weak pull-ups on PORTB.
REGISTER 4-2: OPTION REGISTER (ADDRESS 81H)
R/W-1
RBPU
bit7
R/W-1
R/W-1
R/W-1
T0SE
R/W-1
PSA
R/W-1
PS2
R/W-1
PS1
R/W-1
PS0
INTEDG T0CS
R = Readable bit
W = Writable bit
-n = Value at POR reset
bit0
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:
bit 5:
bit 4:
bit 3:
INTEDG: Interrupt Edge Select bit
1= Interrupt on rising edge of RB0/INT pin
0= Interrupt on falling edge of RB0/INT pin
T0CS: TMR0 Clock Source Select bit
1= Transition on RA4/T0CKI pin
0= Internal instruction cycle clock (CLKOUT)
T0SE: TMR0 Source Edge Select bit
1= Increment on high-to-low transition on RA4/T0CKI pin
0= Increment on low-to-high transition on RA4/T0CKI pin
PSA: Prescaler Assignment bit
1= Prescaler is assigned to the WDT
0= Prescaler is assigned to the Timer0 module
bit 2-0: PS2:PS0: Prescaler Rate Select bits
Bit Value
TMR0 Rate WDT Rate
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
DS40300B-page 20
Preliminary
1999 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
