UART Problem

Hi support,

I have been using Xbee Pro S2 version UART to transmit data at a interval of 4s. However, I realize that for every 6-7 minutes minutes. The UART does not response to my transmitted data within 2 seconds. I was wondering if this a known problem for the module? Please advice.

no one there encounter this problem before?

Are you using sleep functionality and/or flow control in the Xbee Pro? We’re using Xbee S2C SMT modules and had quite a few issues with UART communication, though mostly with data flowing out of the module not in. There were some workarounds, but the newest firmware (4053 for the S2C at least) addressed the issue with data hanging in buffers.

The easiest way to update the firmware that I’m aware of is to get an XBIB-U-SS (or the through-hole equivalent) development board and program through the XCTU software. If the Xbee module is already soldered in place you can put a second module in the development board and remotely update the firmware in the first module over the air (ZigBee). The latest firmware may be available through XCTU’s built in update functionality even if it doesn’t show up on the website.

Good Luck!

Hi Jeremy,

I am not using the sleeping function as both my Xbee module are configured to Coordinator and router, so the sleeping function should be disabled. Yes, i do activated the flow control, CTS and RTS to handle the buffer congestion problem if there is. But apparently, the CTS is not activated at all. Also, for both modules, I am using the latest firmware (21A7).

Could you be seeing this issue on the Coordinators UART? IF so, try setting the DL and DH of the Coordinator to match the SL and SH of the router.

I did not monitor the coordinator and so cant tell if the same problem exist for the coordinator. What I have monitored is the communication between microp UART and Xbee data in and out pin. I can see clearly that the router Xbee doesn’t response to the data sent by the microp through UART on a periodic basis and this phenomenon can last up to 20s. Aren’t the UART comm suppose to work 100%?

HI to all,
I have a problem on pic18f66k80 uart (both 1 nd 2). The problem is that sometimes (average every 5K exchange) a received data is corrupted. The hw was based initially over the FT230 (usb to rs32) after I changed using a commercial usb to rs232 adapter but the probem remain.
Furthermore I changed the baud rate from 115200 to 2400 and the faults decreased (at 2400) but are still remaining.
I am not using the library but I am acceding to the uart register directely
Any suggestion

thank you
maurizio stefani

Sounds like you are simply running out of buffer space and dropping part of the packet. Make sure you are using Flow control properly.