Datasheet

 2015 Microchip Technology Inc. Preliminary DS60001320B-page 577
PIC32MZ Embedded Connectivity with Floating Point Unit (EF) Family
33.0 POWER-SAVING FEATURES
This section describes power-saving features for the
PIC32MZ EF devices. These devices offer various
methods and modes that allow the user to balance
power consumption with device performance. In all of
the methods and modes described in this section,
power-saving is controlled by software.
33.1 Power Saving with CPU Running
When the CPU is running, power consumption can be
controlled by reducing the CPU clock frequency,
lowering the speed of PBCLK7, or selecting a lower
power clock source (i.e., LPRC or S
OSC).
In addition, the Peripheral Bus Scaling mode is available
for each peripheral bus where peripherals are clocked at
reduced speed by selecting a higher divider for the
associated PBCLKx, or by disabling the clock
completely.
33.2 Power-Saving with CPU Halted
Peripherals and the CPU can be Halted or disabled to
further reduce power consumption.
33.2.1 SLEEP MODE
Sleep mode has the lowest power consumption of the
device power-saving operating modes. The CPU and
most peripherals are Halted and the associated clocks
are disabled. Select peripherals can continue to
operate in Sleep mode and can be used to wake the
device from Sleep. See the individual peripheral
module sections for descriptions of behavior in Sleep.
Sleep mode includes the following characteristics:
• There can be a wake-up delay based on the
oscillator selection
• The Fail-Safe Clock Monitor (FSCM) does not
operate during Sleep mode
• The BOR circuit remains operative during Sleep
mode
• The WDT, if enabled, is not automatically cleared
prior to entering Sleep mode
• Some peripherals can continue to operate at limited
functionality in Sleep mode. These peripherals
include I/O pins that detect a change in the input
signal, WDT, ADC, UART and peripherals that use
an external clock input or the internal LPRC
oscillator (e.g., RTCC, Timer1 and Input Capture).
• I/O pins continue to sink or source current in the
same manner as they do when the device is not in
Sleep
The processor will exit, or ‘wake-up’, from Sleep on one
of the following events:
• On any interrupt from an enabled source that is
operating in Sleep. The interrupt priority must be
greater than the current CPU priority.
• On any form of device Reset
• On a WDT time-out
If the interrupt priority is lower than or equal to the
current priority, the CPU will remain Halted, but the
peripheral bus clocks will start running and the device
will enter into Idle mode.
33.2.2 IDLE MODE
In Idle mode, the CPU is Halted; however, all clocks are
still enabled. This allows peripherals to continue to
operate. Peripherals can be individually configured to
Halt when entering Idle by setting their respective SIDL
bit. Latency, when exiting Idle mode, is very low due to
the CPU oscillator source remaining active.
The device enters Idle mode when the SLPEN bit
(OSCCON<4>) is clear and a WAIT instruction is
executed.
The processor will wake or exit from Idle mode on the
following events:
• On any interrupt event for which the interrupt source
is enabled. The priority of the interrupt event must
be greater than the current priority of the CPU. If the
priority of the interrupt event is lower than or equal
to current priority of the CPU, the CPU will remain
Halted and the device will remain in Idle mode.
• On any form of device Reset
• On a WDT time-out interrupt
Note: This data sheet summarizes the
features of the PIC32MZ EF family of
devices. It is not intended to be a
comprehensive reference source. To
complement the information in this data
sheet, refer to Section 10. “Power-
Saving Features” (DS60001130) in the
“PIC32 Family Reference Manual”, which
is available from the Microchip web site
(
www.microchip.com/PIC32).