PIC24EP64MC204-E/PT Microchip Technology, PIC24EP64MC204-E/PT Datasheet - Page 163

• Manufacturer Part Number: PIC24EP64MC204-E/PT
• Description: 16 Bit MCU, 64KB Flash, 8KB RAM, 60 MHz, 44 Pin, MCPWM,QEI, 3 OpAmp, 4 Comp, PTG
• Manufacturer: Microchip Technology

10.3
The
consumption are changing clock speed and invoking
one
circumstances, this cannot be practical. For example, it
may be necessary for an application to maintain
uninterrupted synchronous communication, even while
it is doing nothing else. Reducing system clock speed
can introduce communication errors, while using a
power-saving
completely.
Doze mode is a simple and effective alternative method
to reduce power consumption while the device is still
executing code. In this mode, the system clock
continues to operate from the same source and at the
same speed. Peripheral modules continue to be
clocked at the same speed, while the CPU clock speed
is reduced. Synchronization between the two clock
domains is maintained, allowing the peripherals to
access the SFRs while the CPU executes code at a
slower rate.
Doze mode is enabled by setting the DOZEN bit
(CLKDIV<11>). The ratio between peripheral and core
clock speed is determined by the DOZE<2:0> bits
(CLKDIV<14:12>).
configurations, from 1:1 to 1:128, with 1:1 being the
default setting.
Programs can use Doze mode to selectively reduce
power consumption in event-driven applications. This
allows clock-sensitive functions, such as synchronous
communications, to continue without interruption while
the CPU idles, waiting for something to invoke an
interrupt routine. An automatic return to full-speed CPU
operation on interrupts can be enabled by setting the
ROI bit (CLKDIV<15>). By default, interrupt events
have no effect on Doze mode operation.
For example, suppose the device is operating at
20 MIPS and the ECAN module has been configured
for 500 kbps based on this device operating speed. If
the device is placed in Doze mode with a clock
frequency ratio of 1:4, the ECAN module continues to
communicate at the required bit rate of 500 kbps, but
the CPU now starts executing instructions at a
frequency of 5 MIPS.
 2011-2012 Microchip Technology Inc.
dsPIC33EPXXXGP50X, dsPIC33EPXXXMC20X/50X, AND PIC24EPXXXGP/MC20X
preferred
of
Doze Mode
the
mode
power-saving
strategies
There
can
stop
for
are
modes.
reducing
eight
communications
In
possible
power
some
10.4
The Peripheral Module Disable (PMD) registers
provide a method to disable a peripheral module by
stopping all clock sources supplied to that module.
When a peripheral is disabled using the appropriate
PMD control bit, the peripheral is in a minimum power
consumption state. The control and status registers
associated with the peripheral are also disabled, so
writes to those registers do not have effect and read
values are invalid.
A peripheral module is enabled only if both the
associated bit in the PMD register is cleared and the
peripheral is supported by the specific dsPIC
variant. If the peripheral is present in the device, it is
enabled in the PMD register by default.
10.5
Many useful resources are provided on the main prod-
uct page of the Microchip web site for the devices listed
in this data sheet. This product page, which can be
accessed using this link, contains the latest updates
and additional information.
10.5.1
• Section 9. “Watchdog Timer and Power-Saving
• Code Samples
• Application Notes
• Software Libraries
• Webinars
• All related dsPIC33E/PIC24E Family Reference
• Development Tools
Note:
Note:
Modes” (DS70615)
Manuals Sections
Peripheral Module Disable
Power-Saving Resources
If a PMD bit is set, the corresponding
module is disabled after a delay of one
instruction cycle. Similarly, if a PMD bit is
cleared, the corresponding module is
enabled after a delay of one instruction
cycle (assuming the module control regis-
ters are already configured to enable
module operation).
In the event you are not able to access the
product page using the link above, enter
this URL in your browser:
http://www.microchip.com/wwwproducts/
Devices.aspx?dDocName=en555464
KEY RESOURCES
DS70657F-page 163
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