PIC16F688

Manufacturer Part NumberPIC16F688
ManufacturerMicrochip Technology Inc.
PIC16F688 datasheet
 


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Page 16/202:

OPTION Register

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PIC16F688
2.2.2.2

OPTION Register

The OPTION register is a readable and writable
register, which contains various control bits to
configure:
• Timer0/WDT prescaler
• External RA2/INT interrupt
• Timer0
• Weak pull-ups on PORTA
REGISTER 2-2:
OPTION_REG: OPTION REGISTER
R/W-1
R/W-1
R/W-1
RAPU
INTEDG
T0CS
bit 7
Legend:
R = Readable bit
W = Writable bit
-n = Value at POR
‘1’ = Bit is set
bit 7
RAPU: PORTA Pull-up Enable bit
1 = PORTA pull-ups are disabled
0 = PORTA pull-ups are enabled by individual PORT latch values
bit 6
INTEDG: Interrupt Edge Select bit
1 = Interrupt on rising edge of RA2/INT pin
0 = Interrupt on falling edge of RA2/INT pin
bit 5
T0CS: Timer0 Clock Source Select bit
1 = Transition on RA2/T0CKI pin
0 = Internal instruction cycle clock (F
bit 4
T0SE: Timer0 Source Edge Select bit
1 = Increment on high-to-low transition on RA2/T0CKI pin
0 = Increment on low-to-high transition on RA2/T0CKI pin
bit 3
PSA: Prescaler Assignment bit
1 = Prescaler is assigned to the WDT
0 = Prescaler is assigned to the Timer0 module
bit 2-0
PS<2:0>: Prescaler Rate Select bits
Bit Value
Timer0 Rate
000
001
010
011
100
101
110
111
DS41203D-page 14
Note:
To achieve a 1:1 prescaler assignment for
Timer0, assign the prescaler to the WDT
by setting PSA bit of the OPTION register
to ‘1’. See Section 5.1.3 “Software
Programmable Prescaler”.
R/W-1
R/W-1
R/W-1
T0SE
PSA
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
/4)
OSC
WDT Rate
1 : 2
1 : 1
1 : 4
1 : 2
1 : 8
1 : 4
1 : 16
1 : 8
1 : 32
1 : 16
1 : 64
1 : 32
1 : 128
1 : 64
1 : 256
1 : 128
R/W-1
R/W-1
PS2
PS1
PS0
bit 0
x = Bit is unknown
© 2007 Microchip Technology Inc.