Microchip Technology MA160014 Data Sheet
PIC18(L)F2X/4XK22
DS41412F-page 48
2010-2012 Microchip Technology Inc.
3.1.3
MULTIPLE FUNCTIONS OF THE
SLEEP COMMAND
SLEEP COMMAND
The power-managed mode that is invoked with the
SLEEP
SLEEP
instruction is determined by the value of the
IDLEN bit at the time the instruction is executed. If
IDLEN = 0, when SLEEP is executed, the device enters
the Sleep mode and all clocks stop and minimum
power is consumed. If IDLEN = 1, when SLEEP is
executed, the device enters the IDLE mode and the
system clock continues to supply a clock to the
peripherals but is disconnected from the CPU.
IDLEN = 0, when SLEEP is executed, the device enters
the Sleep mode and all clocks stop and minimum
power is consumed. If IDLEN = 1, when SLEEP is
executed, the device enters the IDLE mode and the
system clock continues to supply a clock to the
peripherals but is disconnected from the CPU.
3.2
Run Modes
In the Run modes, clocks to both the core and
peripherals are active. The difference between these
modes is the clock source.
peripherals are active. The difference between these
modes is the clock source.
3.2.1
PRI_RUN MODE
The PRI_RUN mode is the normal, full-power
execution mode of the microcontroller. This is also the
default mode upon a device Reset, unless Two-Speed
Start-up is enabled (see
execution mode of the microcontroller. This is also the
default mode upon a device Reset, unless Two-Speed
Start-up is enabled (see
for details). In this mode, the
device is operated off the oscillator defined by the
FOSC<3:0> bits of the CONFIG1H Configuration
register.
FOSC<3:0> bits of the CONFIG1H Configuration
register.
3.2.2
SEC_RUN MODE
In SEC_RUN mode, the CPU and peripherals are
clocked from the secondary external oscillator. This
gives users the option of lower power consumption
while still using a high accuracy clock source.
clocked from the secondary external oscillator. This
gives users the option of lower power consumption
while still using a high accuracy clock source.
SEC_RUN mode is entered by setting the SCS<1:0>
bits to ‘01’. When SEC_RUN mode is active, all of the
following are true:
bits to ‘01’. When SEC_RUN mode is active, all of the
following are true:
• The device clock source is switched to the SOSC
oscillator (see
)
• The primary oscillator is shut down
• The SOSCRUN bit (OSCCON2<6>) is set
• The OSTS bit (OSCCON2<3>) is cleared
On transitions from SEC_RUN mode to PRI_RUN
mode, the peripherals and CPU continue to be clocked
from the SOSC oscillator, while the primary clock is
started. When the primary clock becomes ready, a
clock switch back to the primary clock occurs (see
mode, the peripherals and CPU continue to be clocked
from the SOSC oscillator, while the primary clock is
started. When the primary clock becomes ready, a
clock switch back to the primary clock occurs (see
). When the clock switch is complete, the
SOSCRUN bit is cleared, the OSTS bit is set and the
primary clock is providing the clock. The IDLEN and
SCS bits are not affected by the wake-up and the
SOSC oscillator continues to run.
primary clock is providing the clock. The IDLEN and
SCS bits are not affected by the wake-up and the
SOSC oscillator continues to run.
3.2.3
RC_RUN MODE
In RC_RUN mode, the CPU and peripherals are
clocked from the internal oscillator block using the
INTOSC multiplexer. In this mode, the primary clock is
shut down. When using the LFINTOSC source, this
mode provides the best power conservation of all the
Run modes, while still executing code. It works well for
user applications which are not highly timing-sensitive
or do not require high-speed clocks at all times. If the
primary clock source is the internal oscillator block –
either LFINTOSC or INTOSC (MFINTOSC or
HFINTOSC) – there are no distinguishable differences
between the PRI_RUN and RC_RUN modes during
execution. Entering or exiting RC_RUN mode,
however, causes a clock switch delay. Therefore, if the
primary clock source is the internal oscillator block,
using RC_RUN mode is not recommended.
clocked from the internal oscillator block using the
INTOSC multiplexer. In this mode, the primary clock is
shut down. When using the LFINTOSC source, this
mode provides the best power conservation of all the
Run modes, while still executing code. It works well for
user applications which are not highly timing-sensitive
or do not require high-speed clocks at all times. If the
primary clock source is the internal oscillator block –
either LFINTOSC or INTOSC (MFINTOSC or
HFINTOSC) – there are no distinguishable differences
between the PRI_RUN and RC_RUN modes during
execution. Entering or exiting RC_RUN mode,
however, causes a clock switch delay. Therefore, if the
primary clock source is the internal oscillator block,
using RC_RUN mode is not recommended.
This mode is entered by setting the SCS1 bit to ‘1’. To
maintain software compatibility with future devices, it is
recommended that the SCS0 bit also be cleared, even
though the bit is ignored. When the clock source is
switched to the INTOSC multiplexer (see
maintain software compatibility with future devices, it is
recommended that the SCS0 bit also be cleared, even
though the bit is ignored. When the clock source is
switched to the INTOSC multiplexer (see
the primary oscillator is shut down and the OSTS bit is
cleared. The IRCF<2:0> bits (OSCCON<6:4>) may be
modified at any time to immediately change the clock
speed.
cleared. The IRCF<2:0> bits (OSCCON<6:4>) may be
modified at any time to immediately change the clock
speed.
When the IRCF bits and the INTSRC bit are all clear,
the INTOSC output (HFINTOSC/MFINTOSC) is not
enabled and the HFIOFS and MFIOFS bits will remain
clear. There will be no indication of the current clock
source. The LFINTOSC source is providing the device
clocks.
the INTOSC output (HFINTOSC/MFINTOSC) is not
enabled and the HFIOFS and MFIOFS bits will remain
clear. There will be no indication of the current clock
source. The LFINTOSC source is providing the device
clocks.
If the IRCF bits are changed from all clear (thus,
enabling the INTOSC output) or if INTSRC or MFIOSEL
is set, then the HFIOFS or MFIOFS bit is set after the
INTOSC output becomes stable. For details, see
enabling the INTOSC output) or if INTSRC or MFIOSEL
is set, then the HFIOFS or MFIOFS bit is set after the
INTOSC output becomes stable. For details, see
.
Clocks to the device continue while the INTOSC source
stabilizes after an interval of T
stabilizes after an interval of T
IOBST
.
If the IRCF bits were previously at a non-zero value, or
if INTSRC was set before setting SCS1 and the
INTOSC source was already stable, then the HFIOFS
or MFIOFS bit will remain set.
if INTSRC was set before setting SCS1 and the
INTOSC source was already stable, then the HFIOFS
or MFIOFS bit will remain set.
Note:
The secondary external oscillator should
already be running prior to entering
SEC_RUN mode. If the SOSCGO bit or
any of the TxSOSCEN bits are not set
when the SCS<1:0> bits are set to ‘01’,
entry to SEC_RUN mode will not occur
until SOSCGO bit is set and secondary
external oscillator is ready.
already be running prior to entering
SEC_RUN mode. If the SOSCGO bit or
any of the TxSOSCEN bits are not set
when the SCS<1:0> bits are set to ‘01’,
entry to SEC_RUN mode will not occur
until SOSCGO bit is set and secondary
external oscillator is ready.