PIC16F720_13 Datasheet, PDF (68/254 Pages) Microchip Technology – 20-Pin Flash Microcontrollers

PIC16(L)F720/721
7.5 Oscillator Tuning
The INTOSC is factory calibrated but can be adjusted
in software by writing to the OSCTUNE register
(Register 7-2).
The default value of the OSCTUNE register is ‘0’. The
value is a 6-bit two’s complement number.
When the OSCTUNE register is modified, the INTOSC
frequency will begin shifting to the new frequency. Code
execution continues during this shift. There is no
indication that the shift has occurred.
REGISTER 7-2: OSCTUNE: OSCILLATOR TUNING REGISTER
U-0
—
bit 7
U-0
R/W-0
R/W-0
R/W-0
R/W-0
—
TUN5
TUN4
TUN3
TUN2
R/W-0
TUN1
R/W-0
TUN0
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 7-6
bit 5-0
Unimplemented: Read as ‘0’
TUN<5:0>: Frequency Tuning bits
01 1111 = Maximum frequency
01 1110 =
•
•
•
00 0001 =
00 0000 = Oscillator module is running at the factory-calibrated frequency.
11 1111 =
•
•
•
10 0000 = Minimum frequency
DS41430D-page 68
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