Hi guys,
I use an xBee Explorer Regulated with an xBee Pro 802.15.4. The first one has an smd LED hooked up with the APM Tx wire, so I could verify if something is sent from the APM.
It was blinking even with the UART0/2 connection, but quite faintly. (Which is understandable, as there are a few 1k resistors in the MUX circuit). The xBee however did not pick up the signal, because I was not receiving anything on the remote side.
After spending several hours, I've finally hooked up the Tx signal directly from the UART0 outlet on the APM board, and surprise, immediately works, xBee now gets the signal properly. (The LED on the xBee Explorer is now blinking brighter, but once again, I don't believe that's something that could make the difference.)
Because all the xBee Explorer puts in between the Rx pin of xBee and Tx pin of APM is a single diode (5V -> 3.3V), I tend to think this is something the MUX circuit of the APM board messes up.
I'd be curios to check the shape of the signal coming out of UART2/0, but unfortunately I don't have an oscilloscope.
Board otherwise fully functional, APM version 2.5.1.
I can live without it, but we could debug it for the future generation :)
Cheers, Attila
Replies
It's not an APM problem but the XBee adapter boards, lots of complaints in sparkfun comments for this same reason
I have exactly the same problem. Any news from the APM guys if it is a hardware/software problem that we could solve without sending back the boards?