PIC16F88-I/SO Microchip Technology Inc., PIC16F88-I/SO Datasheet - Page 20

• Manufacturer Part Number: PIC16F88-I/SO
• Description: 18 PIN, 7 KB FLASH, 368 RAM, 16 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC16F88-I/SO

• A/d Inputs: 7-Channel, 10-Bit
• Comparators: 2
• Cpu Speed: 5 MIPS
• Eeprom Memory: 256 Bytes
• Input Output: 16
• Interface: I2C/SPI/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 18-pin SOIC
• Programmable Memory: 7K Bytes
• Ram Size: 368 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

PIC16F87/88
2.2.2.2
The OPTION_REG register is a readable and writable
register that 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:
DS30487C-page 18
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2-0
OPTION_REG Register
OPTION_REG: OPTION CONTROL REGISTER (ADDRESS 81h, 181h)
bit 7
RBPU
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/C2OUT pin
0 = Internal instruction cycle clock (CLKO)
T0SE: TMR0 Source Edge Select bit
1 = Increment on high-to-low transition on RA4/T0CKI/C2OUT pin
0 = Increment on low-to-high transition on RA4/T0CKI/C2OUT 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
Legend:
R = Readable bit
-n = Value at POR
R/W-1
RBPU
Bit Value
000
001
010
011
100
101
110
111
:
PORTB Pull-up Enable bit
INTEDG
R/W-1
TMR0 Rate
1 : 128
1 : 256
1 : 16
1 : 32
1 : 64
1 : 2
1 : 4
1 : 8
R/W-1
T0CS
WDT Rate
W = Writable bit
‘1’ = Bit is set
1 : 128
1 : 16
1 : 32
1 : 64
1 : 1
1 : 2
1 : 4
1 : 8
R/W-1
T0SE
Note:
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
R/W-1
To achieve a 1:1 prescaler assignment for
the TMR0 register, assign the prescaler to
the Watchdog Timer. Although the pres-
caler can be assigned to either the WDT or
Timer0, but not both, a new divide counter
is implemented in the WDT circuit to give
multiple WDT time-out selections. This
allows TMR0 and WDT to each have their
own scaler. Refer to Section 15.12
“Watchdog Timer (WDT)” for further
details.
PSA
R/W-1
PS2
 2005 Microchip Technology Inc.
x = Bit is unknown
R/W-1
PS1
R/W-1
PS0
bit 0