PIC18F23K22 Datasheet, PDF (53/492 Pages) Microchip Technology – 28/40/44-Pin, Low-Power, High-Performance Microcontrollers with nanoWatt XLP Technology

PIC18(L)F2X/4XK22
FIGURE 3-7:
TRANSITION TIMING FOR WAKE FROM IDLE TO RUN MODE
Q1
OSC1
CPU Clock
Peripheral
Clock
Program
Counter
TCSD
PC
Wake Event
Q2
Q3
Q4
3.4.3 RC_IDLE MODE
In RC_IDLE mode, the CPU is disabled but the periph-
erals continue to be clocked from the internal oscillator
block from the HFINTOSC multiplexer output. This
mode allows for controllable power conservation during
Idle periods.
From RC_RUN, this mode is entered by setting the
IDLEN bit and executing a SLEEP instruction. If the
device is in another Run mode, first set IDLEN, then set
the SCS1 bit and execute SLEEP. It is recommended
that SCS0 also be cleared, although its value is
ignored, to maintain software compatibility with future
devices. The HFINTOSC multiplexer may be used to
select a higher clock frequency by modifying the IRCF
bits before executing the SLEEP instruction. When the
clock source is switched to the HFINTOSC multiplexer,
the primary oscillator is shut down and the OSTS bit is
cleared.
If the IRCF bits are set to any non-zero value, or either
the INTSRC or MFIOSEL bits are set, the HFINTOSC
output is enabled. Either the HFIOFS or the MFIOFS
bits become set, after the HFINTOSC output stabilizes
after an interval of TIOBST. For information on the
HFIOFS and MFIOFS bits, see Table 3-2.
Clocks to the peripherals continue while the
HFINTOSC source stabilizes. The HFIOFS and
MFIOFS bits will remain set if the IRCF bits were
previously set at a non-zero value or if INTSRC was set
before the SLEEP instruction was executed and the
HFINTOSC source was already stable. If the IRCF bits
and INTSRC are all clear, the HFINTOSC output will
not be enabled, the HFIOFS and MFIOFS bits will
remain clear and there will be no indication of the
current clock source.
When a wake event occurs, the peripherals continue to
be clocked from the HFINTOSC multiplexer output.
After a delay of TCSD following the wake event, the CPU
begins executing code being clocked by the
HFINTOSC multiplexer. The IDLEN and SCS bits are
not affected by the wake-up. The LFINTOSC source
will continue to run if either the WDT or the Fail-Safe
Clock Monitor is enabled.
 2010 Microchip Technology Inc.
Preliminary
DS41412B-page 53