Yesterday I decided to install my APM 2.0 board that I bought few years ago (never used) to my FPV plane. I downloaded mission planner, uploaded arduplane 2.78b firmware to APM board from MP, connection with USB cable worked without problems.
Than I connected 3DR radios that worked good with my old APM1 board, but I was not able to connect :(
When I'm trying to read radio parameters from mission planner, it reads ground and remote side without problems, communication between modules is ok (solid green led). All setting are identical and UART data goes from one radio to another without problems.
Then I reflashed both radios from MP - firmware version changed from 1.5 to 1.9. Still no changes. I sniffed communication with USB-UART adapter - while trying to connect mission planner periodically sends some request bytes to APM board and APM board didn't send nothing back to MP. There is no data at TX port of APM board at all - on startup, while trying to connect, never... I checked APM telemetry port speed setting - it is same as radio setting (57600).
Can you give me some advise about solving my problem, please?