PIC16LC63A-04 Datasheet, PDF (20/184 Pages) Microchip Technology – 8-Bit CMOS Microcontrollers with A/D Converter

PIC16C63A/65B/73B/74B
4.2.2.2 OPTION Register
The OPTION_REG register is a readable and writable
register, which contains various control bits to configure
the TMR0/WDT prescaler, the external INT Interrupt,
TMR0 and the weak pull-ups on PORTB.
Note:
To achieve a 1:1 prescaler assignment for
the TMR0 register, assign the prescaler to
the watchdog timer.
REGISTER 4-2:
OPTION_REG REGISTER (ADDRESS 81h)
R/W-1
R/W-1
R/W-1
R/W-1
RBPU INTEDG T0CS
T0SE
bit 7
R/W-1
PSA
R/W-1
PS2
R/W-1
PS1
R/W-1
PS0
bit 0
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 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
PS2:PS0: Prescaler Rate Select bits
Bit Value TMR0 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
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
DS30605C-page 20
 2000 Microchip Technology Inc.