Microchip Technology IC PIC MCU PIC16F1937-I/PT TQFP-44 MCP PIC16F1937-I/PT Scheda Tecnica
Codici prodotto
PIC16F1937-I/PT
PIC16(L)F1934/6/7
DS41364E-page 72
2008-2011 Microchip Technology Inc.
5.2.2
INTERNAL CLOCK SOURCES
The device may be configured to use the internal oscil-
lator block as the system clock by performing one of the
following actions:
• Program the FOSC<2:0> bits in Configuration
lator 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.
5.2.2.1
HFINTOSC
The High-Frequency Internal Oscillator (HFINTOSC) is
a factory calibrated 16 MHz internal clock source. The
frequency of the HFINTOSC can be altered via
software using the OSCTUNE register (
a factory calibrated 16 MHz internal clock source. The
frequency of the HFINTOSC can be altered via
software using the OSCTUNE register (
The output of the HFINTOSC connects to a postscaler
and multiplexer (see
and multiplexer (see
frequencies derived from the HFINTOSC can be
selected via software using the IRCF<3:0> bits of the
OSCCON register. See
selected via software using the IRCF<3:0> bits of the
OSCCON register. See
for more information.
The HFINTOSC is enabled by:
• Configure the IRCF<3:0> bits of the OSCCON
• Configure the IRCF<3:0> bits of the OSCCON
register for the desired HF frequency, and
• FOSC<2:0> = 100, or
• Set the System Clock Source (SCS) bits of the
• Set the System Clock Source (SCS) bits of the
OSCCON register to ‘1x’.
The High-Frequency Internal Oscillator Ready bit
(HFIOFR) of the OSCSTAT register indicates when the
HFINTOSC is running and can be utilized.
The High-Frequency Internal Oscillator Status Locked
bit (HFIOFL) of the OSCSTAT register indicates when
the HFINTOSC is running within 2% of its final value.
The High-Frequency Internal Oscillator Status Stable
bit (HFIOFS) of the OSCSTAT register indicates when
the HFINTOSC is running within 0.5% of its final value.
(HFIOFR) of the OSCSTAT register indicates when the
HFINTOSC is running and can be utilized.
The High-Frequency Internal Oscillator Status Locked
bit (HFIOFL) of the OSCSTAT register indicates when
the HFINTOSC is running within 2% of its final value.
The High-Frequency Internal Oscillator Status Stable
bit (HFIOFS) of the OSCSTAT register indicates when
the HFINTOSC is running within 0.5% of its final value.
5.2.2.2
MFINTOSC
The Medium-Frequency Internal Oscillator
(MFINTOSC) is a factory calibrated 500 kHz internal
clock source. The frequency of the MFINTOSC can be
altered via software using the OSCTUNE register
(
(MFINTOSC) is a factory calibrated 500 kHz internal
clock source. The frequency of the MFINTOSC can be
altered via software using the OSCTUNE register
(
The output of the MFINTOSC connects to a postscaler
and multiplexer (see
and multiplexer (see
frequencies derived from the MFINTOSC can be
selected via software using the IRCF<3:0> bits of the
OSCCON register. See
selected via software using the IRCF<3:0> bits of the
OSCCON register. See
for more information.
The MFINTOSC is enabled by:
• Configure the IRCF<3:0> bits of the OSCCON
• Configure the IRCF<3:0> bits of the OSCCON
register for the desired HF frequency, and
• FOSC<2:0> = 100, or
• Set the System Clock Source (SCS) bits of the
• Set the System Clock Source (SCS) bits of the
OSCCON register to ‘1x’
The Medium-Frequency Internal Oscillator Ready bit
(MFIOFR) of the OSCSTAT register indicates when the
MFINTOSC is running and can be utilized.
(MFIOFR) of the OSCSTAT register indicates when the
MFINTOSC is running and can be utilized.