Digi Connect EM  e WI-EM - F.A.Q

1) What must be done with the RESET pin on the Connect EM, EM, Wi-EM and Wi-ME?

If the final product has no need for a reset button for the target project nothing need be done to this pin. All of the Connect modules, EM, ME, Wi-EM and Wi-ME, have an internal 10K pull-up resistors connected to this pin, in order to ensure normal operation.

If, however, there is a need for a reset button, all that must be done is to connect a momentary switch between RESET on the module and ground. The supervisory circuit of the Connect module will hold the processor in reset for the required 250ms (1/4 second).

No, the Connect modules are not 5V tolerant. The acceptable input voltage range is 3.14-3.45, with 3.3 being typical. Operating the module at a voltage above 3.45 holds the potential for damaging the device.

There are a number of 3.3VDC Voltage Regulators available on the market, from companies such as Digi-Key that would be capable to properly regulating the primary voltage down to an acceptable 3.3V for the Connect module. 

3) With regard to the 802.11af (Power Over Ethernet) specification, do the Connect EM and ME families support end or mid-span PoE?

First one should clarify what is meant by mid and end-span.

• Mid-span: +48VDC is delivered across the Ethernet cable using the unused pins (4, 5, 7 & 8).
• End-span: +48VDC is delivered on on the same pins used for data (1,2,3 and 6).

The Connect ME supports only mid-span.

The Connect EM module, itself, does not provide any support for PoE. However, using the version of the module with no onboard Ethernet connector (P/N DC-EM-02T-NC) a full PoE implementation is possible. The EM development board, however, only provides support for mid-span.