Digi Connect ME 9210 Low Power Mode

Embedded Devices NET+OS
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1

I am using the Digi Connect ME 9210 EtherNet embedded system-on-module - but the power consumption is too high for the 3.3V supply I am using.

During power up the ME9210 consumes over 300mA which is too much and shorts the 3.3V supply I have available (resetting the ME9210). Once the ME9210 is powered up this drops to about 100mA which is acceptable.

Can the ME9210 power up current be reduced? - Even if this sacrifices power up time. I can enable low power mode (set BSP_LOW_POWER_MODE_ENABLE to TRUE in NET+OS), however this only reduces power consumption after the power up sequence.

2

I would start with the Digi Connect ME Hardware Reference manual.

http://ftp1.digi.com/support/documentation/90000897_K.pdf
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
PHY.
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)
Wake

3

In NS7520 to NS9210 migration schematics
http://ftp1.digi.com/support/documentation/NS7520_to_NS9210_Migration_Guide.pdf

I see that NS9210 can be operated in NS7520 mode.

@Campbell, is this what you were explaining?

4

Thank you for the answer.
The power saving sample gave me the same results as before.

  • Greater than 300mA during power up (lasts about 2 seconds)
  • Drops to about 100mA after power up sequence when CatNap mode active

By setting BSP_FAST_BOOT_OPTION to TRUE allows for a faster boot up sequence and the 300mA initial current only lasts less than 1 second. However I still have the same problem that 300mA is too much. The 3.3V supply I am using is limited to 250mA.

I assume it would be possible to slow the processor down and therefore consume less current, even if it takes longer to start up. Maybe by altering the PLL or something similar?

5

Thank you for your answer.
Is there a way to use these bootstrapping options on the Digi connect ME9210? It looks like there are only GPIO pins external to the ME9210 and I assume the A1,2,3 pins are internal to the unit?

6

Is there a solution for this problem.
We have the same were upgrading from Digi Connect ME to the Digi Connect ME 9210 causes the 3.3V rail to dip below 3.0V and restarting the ME 9210

Benno