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CC2745R10-Q1: Is it possible using RTT ranging in CS with SDK 9.14.0.39

chen jinwei
Intellectual 280 points

Part Number: CC2745R10-Q1

Hi, TI

     In the car_node sample with SDK 9.14.0.39. we notice that RTT data is not used when posting the data to algorithm.  The following is the code snippet. Could you help  to check if the RTT mode work OK now. As we test, the timestamp in mode1 and mode3 is unnormal . 

CS data processing :

1.1.jpg

 

RTT TOD-TOA

3.1.jpg

  • 0
    TI__Genius 9805 points

    Hello, 

    Mode 1 steps are supported in 9.14.00.39. Unfortunately, Mode 1 steps have not been fully incorporated into the application-level APIs. 

    Configuring Mode 1 using the HCI commands will work. 

    The mode 1 data will not be used by the algorithm as the data is a time, and not PCT data. 

    Thanks,

    Isaac

  • 0 in reply to Isaac Larson
    Intellectual 280 points

    Hi Isaac

         We config the CS main mode as 3  and  printf  the value of ToDToA in  CS_modeThreeStep_t.   The value of ToDToA  in  local as initiator  is smaller the ToDToA in remote reported by RAS.  To my understanding,if we want to range with RTT,  ToDToA in local as initiator should be larger the value report by RAS.  Is there any misunderstanding?     Also the real distance between  two TI EVM as initiator and reflector is about 1m. But we found the value of ToDToA is larger than 300ns,  which mean the distance is large than 30m. 

         We noticed that before enable CS procedure ,  the FAE table not be used.  Does this affect RTT value. What we can do if we want to use the RTT to caculate the distance。 Thank you！

  • 0 in reply to chen jinwei
    TI__Genius 9805 points

    Hello Chen, 

    Currently we do not have a function to convert RTT timing data to distance. 

    Your understanding of the initiator ToDToA and reflector ToDToA is correct. The value from the initiator should be larger than the reflector. 

    Can you send me a screenshot of the timing data you are seeing? Additionally, can you show me how you are parsing the RTT data from the CS_modeThreeStep_t struct? 

    Thanks,
    Isaac 

  • 0 in reply to Isaac Larson
    Intellectual 280 points

    Hi, Isaac

           1. First we set main_mode equal 3 in cs_config_params. 

            2. Define two global array to save ToDToA data in the file of App_cs_process.c

                uint16_t  u16LocalRTT[72];  

                uint16_t u16RemoteRTT[72]

            3. In the function of csProcess_ProcessSubeventResultsSteps, we save the ToDToA value when stepMode equal 3. 

               In  the function of csProcess_ProcessSubeventResultsStepsRAS . we save the ToDToA value wen stepMode equal 3. 

            4. Debug in CCS,  observe the value in u16LocalRTT[72]  and u16RemoteRTT. 

                You can see some ToDToa in u16LocalRTT are smaller than the ToDToa in u16RemoteRTT.  

                The RTT timestamp I have printed out and show to you  is the diff  of RTT as  u16LocalRTT[i]-u16RemoteRTT[i ]  ,i is 0 to 71. 

  • 0 in reply to chen jinwei
    TI__Genius 9805 points

    Hello Chen, 

    Let me do some more research on how the RTT values are sent to the application level and get back to you. I will provide a response by Friday (12/15). 

    Thanks,
    Isaac