Information

PIC18F1220/1320
DS80244D-page 2 © 2009 Microchip Technology Inc.
4. Module: Oscillator (INTOSC)
The Least Significant bit of the OSCTUNE register,
TUN0 (OSCTUNE<0>), is not implemented. As a
result, incrementing or decrementing the
OSCTUNE register will not have the expected
single-step change on the frequency of INTOSC.
This is expected to be a permanent design change
for the device.
Work around
For incremental changes to OSCTUNE, copy its
contents to WREG, increment or decrement
WREG twice, then write WREG back to
OSCTUNE. This has the effect of incrementing or
decrementing TUN<5:1> while maintaining TUN0
clear (the smallest possible adjustment in this
silicon revision).
It is also possible to decrement OSCTUNE
directly. Each direct decrement decreases the
value of OSCTUNE by two (TUN0 remains clear).
If incremental change is not required, OSCTUNE
can also be written to directly with any value.
Date Codes that pertain to this issue:
All engineering and production devices.
5. Module: Oscillator (INTRC)
The 31 kHz internal RC oscillator source (INTRC)
has been configured as a separate, fixed
frequency source that is calibrated at the factory.
Its output is no longer tunable using the
OSCTUNE register. The INTOSC source remains
tunable using OSCTUNE, as previously
described.
This is expected to be a permanent design change
for the device.
Work around
None.
Date Codes that pertain to this issue:
All engineering and production devices.