Datasheet

PIC16(L)F1454/5/9
DS41639A-page 266 Preliminary  2012 Microchip Technology Inc.
23.2 Clock Accuracy with
Asynchronous Operation
The factory calibrates the internal oscillator block out-
put (INTOSC). However, the INTOSC frequency may
drift as V
DD or temperature changes, and this directly
affects the asynchronous baud rate. Two methods may
be used to adjust the baud rate clock, but both require
a reference clock source of some kind.
The first (preferred) method uses the OSCTUNE
register to adjust the INTOSC output. Adjusting the
value in the OSCTUNE register allows for fine resolution
changes to the system clock source. See
Section 5.2.2
“Internal Clock Sources”
for more information.
The other method adjusts the value in the Baud Rate
Generator. This can be done automatically with the
Auto-Baud Detect feature (see
Section 23.4.1
“Auto-Baud Detect”
). There may not be fine enough
resolution when adjusting the Baud Rate Generator to
compensate for a gradual change in the peripheral
clock frequency.