Interfacing Digi OEM RF Modules to Microcontrollers

Digi radios are compatible with microcontrollers from a variety of vendors. For this reason, Digi does not make recommendations for choosing a specific microcontroller to interface with our radios. However, we can offer a few feature suggestions to consider. All Digi serial OEM Modules use a standard CMOS or TTL UART interface, making it important to also choose a microcontroller with a UART interface. In addition to the standard UART, all existing product except legacy XSC and XTend radios supports a SPI interface while the new XBee3 modules supports I2C as well.

Many of the Digi modules have specific power requirements. Integration will be more seamless if a microcontroller with similar power requirements is used. For example, many of the Digi XBee modules require 2.8 - 3.4 VCC input voltage, so it would be beneficial to choose a microcontroller with corresponding input voltage requirements. To be clear,  unless otherwise listed in the product manual, the inputs to the Digi XBee module are NOT 5V tolerant and cannot accept a voltage level higher than the VCC listing for the module on any pin. Applying a voltage higher than the modules VCC limit will damage the module and void the warranty.

If utilizing one of the surface mount (SMT) or (MMT) Digi XBee modules, the XBee SMT and MMT module is designed to be soldered in place. This creates some unique challenges for troubleshooting and reprogramming the XBee. The primary means of updating and configuring the module will be via over-the-air configuration, however there are some factors that will cause the module to not be accessible in this way (bad firmware flash, unknown PAN ID, etc.) Reworking the module after it has been installed will void your warranty, so it is recommended to have a physical programming header installed on your board. This header will need to allow you to access the necessary pins of the Digi XBee to configure the module or perform a recovery if needed. Note that two devices cannot share the same UART connection, so if a programming header is installed there should be some way to allow the header exclusive access to the XBee, either with a physical jumper or software solution.  Please be sure to check the manual for the the recommended pin connections.