No signal on APM2.0 UART0 and XBEE issue

Hi

My setup is as following:

APM 2.0

XBee-PRO 900 extended range module w/ RPSMA connector  (Laptop Side)  XBP09-DM Firmware 1061

DIYDrone XtreamBee USB Adapter (Laptop Side)

XBee-PRO 900 extended range module w/ wire antenna (APM 2.0 side) XBP09-DM Firmware 1061

DIYDrone XtreamBee Board (APM 2.0 Side).

  • I’m able to successfully test Airlink between the two XBEEs using X-CTU and loopback.
  • I’m able to receive test text over the air link when I use serial testing sketch on APM2.0 board, connecting the XBEE to the side UART0
  • I soldered the UART0/2 MUX jumpers on the bottom of APM 2.0 to select UART0

My 1st Issue is I’m not able to see any signal on the back UART0 connector even when I load the serial test sketch which is giving perfect output on the side UART0. Is this a known bug in APM 2.0 board ?

My 2nd Issue is that I’m not able to establish telemetry over the airlink, I tried 57K & 115K baud rates, I tried HKGCS & APM Planner but no luck (Even when using the long side UART0 port)

Please help me.

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Replies

  • Hi Guys!

    I'm having the same problem as you! The Uart0/2 stopped sending data to my xbee! I haven't tried the UART0 solo... If that does not work do you have other solutions?

    I'm also having some sort of problem when loading a new firmware, when verifying it gives me a strange error, something related to the port not being found or in use, I am not sure! Tomorrow I will post a picture.

    Best Regards,

    AS

  • OK, after i was able to establish a link via the hardwired UART0 port, now i just can't. I wonder WHY. it was able to fetch parameters then eventually fail due to (link isn't fast enogh), but i thought it would work using full battery and ESC power as stated by some other client. Now, it won't connect at all!! I even soldered the UART0/2 MUX, but with no success!!

    PLEASE, HELP !! and can anyone explain a workaround or a procedure to follow to detect where the failure is ? and what about the failed MUX problem i read in another thread ?! 

  • My 2.4.1 board appears to have no micro traces in place (I have a second that is identical with no traces) and the UART does not work. Can connect with USB and flies fine, have a separate issue with the TX/RX LED's that I think may be related. Can you include within the WIKI a good high resolution image of the PCB's so that all the relevant default micro links are visible ? I have a feeling I have to solder a few back in....3692425244?profile=original

  • I just want to get this straight as well regarding the mapping of serial ports on the APM2 (V 2.4.1). Can someone confirm the following:

    Description; Label on Board; Physical position on PCB; Mapping in source code

    USB/FTDI; None; USB connector below SD IF;  FastSerialPort0(Serial):  #define xxx_PORT 0 

    GPS Port; UART1; Next to IN1; FastSerialPort1(Serial):  #define xxx_PORT 1 

    Telemetry Port (When USB not connected); UART0/2;  Next to OUT8; FastSerialPort3(Serial);  #define xxx_PORT 3 

    Telemetry Port (Hardwired); UART2; Side of board next to RESET; FastSerialPort3(Serial);  #define xxx_PORT 3

    Why would the telemetry port (either UART0/2 or UART2) not be named  a logical FastSerialPort2(Serial); #define xxx_PORT 2?  

  • Chris,

    UART0 is as shown, no need to change the wiki if the issue is not common. 3692406550?profile=original

  • 3D Robotics

    Muthanna,

    I'm not sure I'm following. Where is the UART0 that you're referring to? The images in the wiki refer to the standard setup, which is what I use.

    Maybe some boards shipped from the factory with a missing/broken microtrace for the UART selection? If so, we'll correct that. But I'm not understanding why the manual recommendations should change, since that's what thousands of people already use.

  • Chris,

    APM2.0 photo you just posted has Ver 2.4.1 on it, mine is Ver 2.4 (I bought it from 3DR almost one month ago); is there any difference related to our issue ??

  • Known issue in a number of threads. I have the same problem on 2 APM 2.0s. The workaround is to use the hardwired uart 0 on the long side of the board right next to the 2x3 row ICSP header. There is something up with the one listed in the directions as there is a jumper solder pad on the bottom of the APM to connect the port to either uart0 or 2. I have tried without succes to to find the right combination to get uart0 out of the port listed in the directions but jsut use the hardwired one for now.

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