Cannot interface XBee with LPC1769 via UART

Question

Hello, I need some help to communicate XBee S2C via UART with my LPC1769. My problem is that when I send "+++" command via UART the XBee module doesn't answer "OK".
The LPC is sending the data fine because if I connect it to Putty I can see the data going out from the MCU fine, besides, if I type "+++" with my PC's keyboard using Putty, the module answer me "OK". Finally, If I connect the XBee to XCTU I can configure it without problem.
Anyone have an idea about this problem? Should I configure the output of the LPC as OpenDrain or Pull-Down? By the moment Tx and Rx pin are configured as Pull-Up.

Thank you!!

Answer 1

Sounds like a voltage issues between the DI and DO lines on how they are connected. Try crossing them so that Di of the XBee is connected to the DO of the processor.

Answer 2

i think u may be forgot to make common GND to each other.i mean connect xbee GND TO CONTROLLER GND, if xbee power with separate power supply.

Answer 3

I finally found the solution, it's was not the voltage either the GND connection. It seems that the XBee don't receive the data from the LPC as the PuTTy does, I change the type of value and I succed in comunnicationg the LPC1769 with my XBee modules.