PIC18F97J60_11 Datasheet, PDF (59/492 Pages) Microchip Technology – 64/80/100-Pin, High-Performance, 1-Mbit Flash Microcontrollers with Ethernet

PIC18F97J60 FAMILY
4.3 Sleep Mode
The power-managed Sleep mode is identical to the
legacy Sleep mode offered in all other PIC MCU
devices. It is entered by clearing the IDLEN bit (the
default state on device Reset) and executing the
SLEEP instruction. This shuts down the selected
oscillator (Figure 4-5). All clock source status bits are
cleared.
Entering the Sleep mode from any other mode does not
require a clock switch. This is because no clocks are
needed once the controller has entered Sleep. If the
WDT is selected, the INTRC source will continue to
operate. If the Timer1 oscillator is enabled, it will also
continue to run.
When a wake event occurs in Sleep mode (by interrupt,
Reset or WDT time-out), the device will not be clocked
until the clock source selected by the SCS<1:0> bits
becomes ready (see Figure 4-6), or it will be clocked
from the internal oscillator if either the Two-Speed
Start-up or the Fail-Safe Clock Monitor is enabled (see
Section 25.0 “Special Features of the CPU”). In
either case, the OSTS bit is set when the primary clock
is providing the device clocks. The IDLEN and SCS bits
are not affected by the wake-up.
4.4 Idle Modes
The Idle modes allow the controller’s CPU to be
selectively shut down while the peripherals continue to
operate. Selecting a particular Idle mode allows users
to further manage power consumption.
If the IDLEN bit is set to ‘1’ when a SLEEP instruction is
executed, the peripherals will be clocked from the clock
source selected using the SCS<1:0> bits; however, the
CPU will not be clocked. The clock source status bits are
not affected. Setting IDLEN and executing a SLEEP
instruction provides a quick method of switching from a
given Run mode to its corresponding Idle mode.
If the WDT is selected, the INTRC source will continue
to operate. If the Timer1 oscillator is enabled, it will also
continue to run.
Since the CPU is not executing instructions, the only exits
from any of the Idle modes are by interrupt, WDT
time-out or a Reset. When a wake event occurs, CPU
execution is delayed by an interval of TCSD
(Parameter 38, Table 28-12) while it becomes ready to
execute code. When the CPU begins executing code, it
resumes with the same clock source for the current Idle
mode. For example, when waking from RC_IDLE mode,
the internal oscillator block will clock the CPU and periph-
erals (in other words, RC_RUN mode). The IDLEN and
SCS bits are not affected by the wake-up.
While in any Idle mode or Sleep mode, a WDT time-out
will result in a WDT wake-up to the Run mode currently
specified by the SCS<1:0> bits.
FIGURE 4-5:
TRANSITION TIMING FOR ENTRY TO SLEEP MODE
OSC1
CPU
Clock
Peripheral
Clock
Q1 Q2 Q3 Q4 Q1
Sleep
Program
Counter
PC
PC + 2
FIGURE 4-6:
TRANSITION TIMING FOR WAKE FROM SLEEP MODE (HSPLL)
Q1
Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
PLL Clock
Output
CPU Clock
Peripheral
Clock
Program
Counter
TOST⁽¹⁾
TPLL⁽¹⁾
PC
PC + 2
PC + 4
PC + 6
Wake Event
OSTS bit Set
Note 1: TOST = 1024 TOSC; TPLL = 2 ms (approx). These intervals are not shown to scale.
 2011 Microchip Technology Inc.
DS39762F-page 59