I would start with the Digi Connect ME Hardware Reference manual.
Power Management (Digi Connect ME 9210 only)
Using the Digi NET+OS development environment, applications on the Digi Connect ME
9210 are capable of operating the module in several reduced power consumption modes.
These reduced power operating modes utilize the power management mechanisms for the
NS9210 processor for CPU clock scaling and sleep.
In the Clock Scaling mode, the system itself continues to execute instructions, but at a
different clock rate, which can be changed on-the-fly, using Digi’s patented circuitry inside
the NS9210 processor. The clock speed is changed programmatically to lower or raise the
system clock speed, thus reducing or increasing the module’s power footprint, respectively.
Additionally, a Sleep mode is available in which the system stops executing instructions.
Based on the application needs, wake-up triggers can be set up programmatically to
activate the processor back to wherever it left off. In this mode, a drastic power reduction is
realized by reducing the power consumption of the NS9210 processor and the on-module
For sample power consumption figures for normal (typical) and power management related
operation of the Digi Connect ME 9210, see below:
3.3VDC @ 346 mA typical (1.14W)
UART and Ethernet activated
Low Speed Idle Mode (approximate)
3.3VDC @ 186 mA (613 mW)
/16 clock scaling, Ethernet activated
Sleep Mode (approximate)
3.3VDC @ 34 mA (113 mW)