Datasheet

 2013 Microchip Technology Inc. DS22331A-page 81
MCP19111
13.0 OSCILLATOR MODES
The MCP19111 has one oscillator configuration which
is an 8 MHz internal oscillator.
13.1 Internal Oscillator (INTOSC)
The Internal Oscillator module provides a system
clock source of 8 MHz. The frequency of the internal
oscillator can be trimmed with a calibration value in the
OSCTUNE register.
13.2 Oscillator Calibration
The 8 MHz internal oscillator is factory calibrated. The
factory calibration values reside in the read-only
Calibration Word 1 register. These values must be read
from the Calibration Word 1 register and stored in the
OSCCAL register. Refer to Section 18.0 “Flash
Program Memory Control” for the procedure on
reading from program memory.
13.3 Frequency Tuning in User Mode
In addition to the factory calibration, the base
frequency can be tuned in the user's application. This
frequency tuning capability allows the user to deviate
from the factory calibrated frequency. The user can
tune the frequency by writing to the OSCTUNE
register (see Register 13-1).
Note 1: The FCAL<6:0> bits from the Calibration
Word 1 register must be written into the
OSCCAL register to calibrate the internal
oscillator.
REGISTER 13-1: OSCTUNE – OSCILLATOR TUNING REGISTER
U-0 U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
— — — TUN4 TUN3 TUN2 TUN1 TUN0
bit 7 bit 0
Legend:
R = Readable bit P = Programmable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-5 Unimplemented: Read as ‘0’
bit 4-0 TUN<4:0>: Frequency Tuning bits
01111 = Maximum frequency
01110 =
•
•
•
00001 =
00000 = Center frequency. Oscillator Module is running at the calibrated frequency.
11111 =
•
•
•
10000 = Minimum frequency