PIC16F872-I/SP Microchip Technology Inc., PIC16F872-I/SP Datasheet - Page 15

• Manufacturer Part Number: PIC16F872-I/SP
• Description: 28 PIN, 7 KB FLASH, 128 RAM, 22 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC16F872-I/SP

• A/d Inputs: 5-Channel, 10-Bit
• Cpu Speed: 5 MIPS
• Eeprom Memory: 64 Bytes
• Input Output: 22
• Interface: I2C/SPI
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 28-pin SPDIP
• 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:
© 2006 Microchip Technology Inc.
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2-0
Note:
OPTION_REG Register
When using low voltage ICSP programming (LVP) and the pull-ups on PORTB are enabled, bit 3
in the TRISB register must be cleared to disable the pull-up on RB3 and ensure the proper oper-
ation of the device
OPTION_REG REGISTER (ADDRESS 81h, 181h)
Bit Value TMR0 Rate WDT Rate
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 (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
Legend:
R = Readable bit
- n = Value at POR
R/W-1
RBPU
000
001
010
011
100
101
110
111
INTEDG
1 : 2
1 : 4
1 : 8
1 : 16
1 : 32
1 : 64
1 : 128
1 : 256
R/W-1
R/W-1
1 : 1
1 : 2
1 : 4
1 : 8
1 : 16
1 : 32
1 : 64
1 : 128
T0CS
W = Writable bit
’1’ = Bit is set
R/W-1
T0SE
Note:
R/W-1
U = Unimplemented bit, read as ‘0’
’0’ = Bit is cleared
PSA
To achieve a 1:1 prescaler assignment for
the TMR0 register, assign the prescaler to
the Watchdog Timer.
R/W-1
PS2
PIC16F872
x = Bit is unknown
R/W-1
PS1
DS30221C-page 13
R/W-1
PS0
bit 0