non standard baudrates

XBee & XBee Gateway XBee - 802.15.4
1

Hello. I’ve tried with some non standard baud rates with AT commands using UART, for example “ATBDF424” is for 62500 bps, *note that the hex value for 62500 is F424 (4 digits), and it works well, I receive the “OK” confirmation, but with more high values it doesn’t work, for example with “ATBD1E848” (5 digits) for 125000 bps it doesn’t work, I think the problem is with more than 4 digits, but really I don’t know. Anybody knows something about this?

Thanks.

2

My initial guess is that your PC COM port doesn’t support baud rates above a certian threshold. 115200 should be fine using the serial board, but anyhting above that, and you need to be using the USB interface to support that speed. The radio will support non standard baud rates up to 250Kbps.

The manual makes reference to the fact that the radio’s clock resolution will adjust to as close a it can to the rate you chose.

3

Hi again. Thanks for your answer Gworle, I know the baud rates supported by the Xbee, but when I send the
“ATBD1E848” command (125kbps), the module responds with “ERROR”. I use a PIC microcontroller with uart connected to the Xbee module. I also use both 9600 and 19200 bps uart connection for communicate between modules, all commands works ok except more than 4 digits after ATBD command. I’m trying more things.

Thanks.

4

The fact that the command issues you an “ERROR” indicates that the parameter value is not supported in the version of firmware you are using on your module. I suspect you have version 1083. To support the non-standard baud rates that you need, you must update the firmware in your radio. Anything greater than the 1083 firmware version will do. 10CD is the latest version downloadable from the web I believe.

5

Thanks very much, then I will continue with 62500 bps, maybe one day I will update the firmware.

Thanks.

6

I have updated modules to 10CD firmware version and now I can work at 125kbps, at 250kb is also supported by the module, but AT commands don’t work at this speed, so I think is required hardware flow control for work with it.

Thanks!!