Техническая Спецификация для Microchip Technology AC244045
PIC16(L)F1825/1829
DS41440C-page 60
2010-2012 Microchip Technology Inc.
FIGURE 5-6:
EXTERNAL RC MODES
The RC oscillator frequency is a function of the supply
voltage, the resistor (R
voltage, the resistor (R
EXT
) and capacitor (C
EXT
) values
and the operating temperature. Other factors affecting
the oscillator frequency are:
• threshold voltage variation
• component tolerances
• packaging variations in capacitance
The user also needs to take into account variation due
to tolerance of external RC components used.
the oscillator frequency are:
• threshold voltage variation
• component tolerances
• packaging variations in capacitance
The user also needs to take into account variation due
to tolerance of external RC components used.
5.2.2
INTERNAL CLOCK SOURCES
The device may be configured to use the internal
oscillator block as the system clock by performing one
of the following actions:
• Program the FOSC<2:0> bits in Configuration
oscillator block as the system clock by performing one
of the following actions:
• Program the FOSC<2:0> bits in Configuration
Word 1 to select the INTOSC clock source, which
will be used as the default system clock upon a
device Reset.
will be used as the default system clock upon a
device Reset.
• Write the SCS<1:0> bits in the OSCCON register
to switch the system clock source to the internal
oscillator during run-time. See
oscillator during run-time. See
for more information.
In INTOSC mode, OSC1/CLKIN is available for general
purpose I/O. OSC2/CLKOUT is available for general
purpose I/O or CLKOUT.
The function of the OSC2/CLKOUT pin is determined
by the state of the CLKOUTEN bit in Configuration
Word 1.
The internal oscillator block has two independent
oscillators and a dedicated Phase-Lock Loop, HFPLL
that can produce one of three internal system clock
sources.
1.
purpose I/O. OSC2/CLKOUT is available for general
purpose I/O or CLKOUT.
The function of the OSC2/CLKOUT pin is determined
by the state of the CLKOUTEN bit in Configuration
Word 1.
The internal oscillator block has two independent
oscillators and a dedicated Phase-Lock Loop, HFPLL
that can produce one of three internal system clock
sources.
1.
The HFINTOSC (High-Frequency Internal
Oscillator) is factory calibrated and operates at
16 MHz. The HFINTOSC source is generated
from the 500 kHz MFINTOSC source and the
dedicated Phase-Lock Loop, HFPLL. The
frequency of the HFINTOSC can be
user-adjusted via software using the OSCTUNE
register (
Oscillator) is factory calibrated and operates at
16 MHz. The HFINTOSC source is generated
from the 500 kHz MFINTOSC source and the
dedicated Phase-Lock Loop, HFPLL. The
frequency of the HFINTOSC can be
user-adjusted via software using the OSCTUNE
register (
2.
The MFINTOSC (Medium-Frequency Internal
Oscillator) is factory calibrated and operates at
500 kHz. The frequency of the MFINTOSC can
be user-adjusted via software using the
OSCTUNE register (
Oscillator) is factory calibrated and operates at
500 kHz. The frequency of the MFINTOSC can
be user-adjusted via software using the
OSCTUNE register (
3.
The LFINTOSC (Low-Frequency Internal
Oscillator) is uncalibrated and operates at
31 kHz.
Oscillator) is uncalibrated and operates at
31 kHz.
OSC2/CLKOUT
C
EXT
R
EXT
PIC
®
MCU
OSC1/CLKIN
F
OSC
/4 or
Internal
Clock
V
DD
V
SS
Recommended values: 10 k
R
EXT
100 k, <3V
3 k
R
EXT
100 k, 3-5V
C
EXT
> 20 pF, 2-5V
Note 1:
Output depends upon CLKOUTEN bit of the
Configuration Word 1.
Configuration Word 1.
I/O
(1)