UART Data Problem

daveonline · Joined: 10 Jul 2010 Posts: 2

Guys,

I have set up 2 XBEE wireless modules in AT mode, one co-ordinator and one router/end device.

There is data communication between them, however the data in and out just isn't correct.

The baud rate on both is 9600, with an 8N1 setup. I am unsure why the data would be scrambled.

I have included a file that shows in the first column what the coordinator is sending, the second column shows the data i am recieving.

Can anyone understand why it is not correct?

Thanks
Dave

ckielstra · Joined: 18 Mar 2004 Posts: 3680 Location: The Netherlands

daveonline · Joined: 10 Jul 2010 Posts: 2

Hi,

You are right, apologies for that i guess i was in a rush and didn't really give much away.
I am currently sending data from the coordinator using the PC and the XBEE supplied software, the end device is connected to the default UART pins on a PIC18F6680. The TX pin is connected to the XBEE through a level shifter to 3v3, as required. The RX pin is also connected to level shift to allow the 3v3 from the XBEE to be switched to 5V. The level shifter is done with transistors, so nice and simple.

I am monitoring the data on the pic using the fget() cmd, and using the MPLAB ICD breaking the code on data IN, and observing the data in a watch window.

The XBEE modules are series 2, using 2.5 protocol.

I hope this extra information helps.

Thanks
Dave

Data from file is below:
First column: Data OUT from PC
Second column: Data IN at PIC