I am having issues with a 900HP unit on a custom board. I cannot get the radio to communicate in transparent mode. The MCU is running at 5v with a level shifter between the RX/TX and Xbee RX/TX. Converts to 3.3v. Also I am only transmitting a hello world Serial dump.
The PCB is a custom board, running an ATMEGA2560 AU MCU. I have checked at the xbee headers I am getting power +3.3v, I have GND, I also have RX and TX (checked with FTDI cable jumpered into pin 2,3 and GND) I can then get the message ("Hello world Serial3") broadcast every 2 seconds (so shouldn't be anywhere near buffer overrun) This is through the FTDI cable and read in minicom. I have disabled flow control ATD6 0 ATD7 0 and am monitoring from another Xbee in minicom. SO in short or all in all. I have power, I have Serial data but I am not seeing this transmit to the partnered radio. The distance is maybe 5cm between units on the bench, there is no source of interference. I have set the units up in XCTU and can transmit back and forth. Connecting through Serial in XCTU and just sending hello world. I can also use Xbee usb bases and see the info in either direction. It leads me to suspect a connection on the PCB BUT I have also used an XBee breakout board jumpered into the PCB power, ground rx and tx. I have swapped rx and tx just in case there has been a cock up on the PCB but no change. My question is this is there something simple I am missing that would account for this? Like I say I can read a Serial message through FTDI cable, I can read power at the headers but still no comms. Also when I issue an ATND command from the monitoring Xbee it finds the other unit and reports its address etc so they are associating and sharing the same basic settings. I'm getting a little confused over what I should test next for this. I think it must be a setting I need to change but I'm not sure where to head to for it.