PIC16F688
3.2
Oscillator Control
The Oscillator Control (OSCCON) register (Figure 3-1)
controls the system clock and frequency selection
options. The OSCCON register contains the following
bits:
• Frequency selection bits (IRCF)
• Frequency Status bits (HTS, LTS)
• System clock control bits (OSTS, SCS)
REGISTER 3-1:
OSCCON: OSCILLATOR CONTROL REGISTER
U-0
—
R/W-1
IRCF2
R/W-1
IRCF1
R/W-0
IRCF0
R-1
OSTS(1)
R-0
R-0
LTS
R/W-0
SCS
HTS
bit 7
bit 0
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
bit 7
Unimplemented: Read as ‘0’
bit 6-4
IRCF<2:0>: Internal Oscillator Frequency Select bits
111= 8 MHz
110= 4 MHz (default)
101= 2 MHz
100= 1 MHz
011= 500 kHz
010= 250 kHz
001= 125 kHz
000= 31 kHz (LFINTOSC)
bit 3
bit 2
bit 1
bit 0
OSTS: Oscillator Start-up Time-out Status bit(1)
1= Device is running from the external clock defined by FOSC<2:0> of the Configuration Word
0= Device is running from the internal oscillator (HFINTOSC or LFINTOSC)
HTS: HFINTOSC Status bit (High Frequency – 8 MHz to 125 kHz)
1= HFINTOSC is stable
0= HFINTOSC is not stable
LTS: LFINTOSC Stable bit (Low Frequency – 31 kHz)
1= LFINTOSC is stable
0= LFINTOSC is not stable
SCS: System Clock Select bit
1= Internal oscillator is used for system clock
0= Clock source defined by FOSC<2:0> of the Configuration Word
Note 1: Bit resets to ‘0’ with Two-Speed Start-up and LP, XT or HS selected as the Oscillator mode or Fail-Safe
mode is enabled.
DS41203D-page 22
© 2007 Microchip Technology Inc.
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