AP08056
Power Saving Features
Overview
Application Note
4
V1.0, 2006-12
1
Overview
This application note describes the various power saving features in the XC800
architecture. It is intended to provide users of the XC866 and XC886/888 with
information and guidelines on how to apply these features to achieve low power
consumption requirements on applications via a combination of techniques which
include:
•
Stopping the CPU clock (Idle Mode)
•
Reducing clock speed (slow-down Mode)
•
Power down of the entire system (Power-Down Mode)
•
Stopping the clocks of individual system components (Peripheral Management)
•
Operating on a lower frequency clock mode
In this document, users can find measurements of the current consumed by the XC866
and XC886/888 devices operating in different power modes. There is also a breakdown
of the current consumed by the peripherals at different clock speeds. Hopefully with
these measurements, the users will have a better understanding of how the different
power saving features can affect the power consumption of the devices and therefore
apply the power saving features effectively. However, these results were meant to serve
as a reference only as the measurements will vary from device to device. The power
consumption can be affected by various factors such as the type of instructions used in
the code, program flow, peripheral settings, measuring equipment, power supply,
temperature and frequency of the oscillator etc.
The measurements in this document were taken from four different devices, XC866-
1FR, XC866-4FR, XC886 and XC888. The XC866-4FR results can be used as a
reference for XC866-2FR.
Unless otherwise stated, all the results were measured under the following conditions:
1. Power supply of 5 V
2. Room temperature of approximately 25
o
C
3. Port 2 of the devices were set to output to disable the analog driver
4. All the other port pins were configured with internal pull-down enabled
5. Peripherals were not programmed to perform any operations
