PIC16F871-I/PT Microchip Technology Inc., PIC16F871-I/PT Datasheet - Page 19

• Manufacturer Part Number: PIC16F871-I/PT
• Description: 44 PIN, 7 KB FLASH, 128 RAM, 33 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC16F871-I/PT

• A/d Inputs: 8-Channel, 10-Bit
• Cpu Speed: 5 MIPS
• Eeprom Memory: 64 Bytes
• Input Output: 33
• Interface: USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 44-pin TQFP
• Programmable Memory: 3.5K Bytes
• Ram Size: 128 Bytes
• Speed: 20 MHz
• Timers: 2-8-bit, 1-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

2.2.2.2
The OPTION_REG register is a readable and writable
register, which contains various control bits to configure
the TMR0 prescaler/WDT postscaler (single assign-
able register known also as the prescaler), the External
INT interrupt, TMR0 and the weak pull-ups on PORTB.
REGISTER 2-2:
 2003 Microchip Technology Inc.
Note:
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2-0
To achieve a 1:1 prescaler assignment for
the TMR0 register, assign the prescaler to
the Watchdog Timer.
OPTION_REG Register
OPTION_REG REGISTER (ADDRESS: 81h,181h)
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
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 (CLKO)
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
Legend:
R = Readable bit
- n = Value at POR
R/W-1
RBPU
Bit Value
INTEDG
000
001
010
011
100
101
110
111
R/W-1
TMR0 Rate
1 : 2
1 : 4
1 : 8
1 : 16
1 : 32
1 : 64
1 : 128
1 : 256
R/W-1
T0CS
W = Writable bit
‘1’ = Bit is set
WDT Rate
1 : 1
1 : 2
1 : 4
1 : 8
1 : 16
1 : 32
1 : 64
1 : 128
R/W-1
T0SE
R/W-1
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
PSA
PIC16F870/871
R/W-1
PS2
x = Bit is unknown
R/W-1
PS1
DS30569B-page 17
R/W-1
PS0
bit 0