Cannot interface XBee with LPC1769 via UART

XBee & XBee Gateway Interface/Development Boards
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1

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!!

2

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.

3

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.

4

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.

5

Can u send me the code that u have written to interface xbee with LPC1769

6

Try crossing them so that Di of the XBee is connected to the DO of the processor.