I have some S3B (xstream) 900MHz Zigbee modules that are experiencing odd behavior. These modules are integrated into a custom board to serve as a wireless UART link between microcontrollers.
Sometimes when the microcontroller boots, it starts receiving data from the radio module even though no traffic is being transmitted. The data received is a 2 byte, increasing counter terminated by a carriage return.
Every module I try shows the same behavior, and the problem does not manifest when the module is plugged into a digi dev board. So I’m convinced the issue is somewhere in the radio initialization routine…possibly the mcu holding some pin high/low during boot that is throwing the module into some special debug mode.
I have looked through the documentation, but cannot find mention of any mode or command that would make the radio continually output this sort of data. Does anyone have an idea what it might be and what would be causing the radio to output it?