Programming Embedded Systems, 2nd Edition

Power-Saving Techniques

A major concern in battery-powered embedded systems design is power consumption. In this section, we take a brief look at areas where embedded software can assist in conserving the system’s vital energy source.

Power consumption is a major concern for portable or battery-operated devices. Power issues, such as how long the device needs to run and whether the batteries can be recharged, need to be thought out ahead of time. In some systems, replacing a battery in a device can be a big expense. This means the system must be conscious of the amount of power it uses and take appropriate steps to conserve battery life.

There are several methods to conserve power in an embedded system, including clock control, power-sensitive processors, low-voltage ICs, and circuit shutdown. Some of these techniques must be addressed by the hardware designer in his selection of the different system ICs. There may be lower-power versions of certain peripherals. Some power-saving techniques are under software control.

It might seem ideal to select the fastest and most powerful processor available for a particular embedded system. However, one of the tasks of the hardware designer is to use just enough processing power to enable the device to get its job done. This helps reduce the power consumed by the device. The processor selected plays a key role in determining the amount of power an embedded system will consume. In addition, some processors can automatically shut down different ...