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CCS/CC3220SF-LAUNCHXL: UART Interfacing using LTE module

Rupam Biswas
Prodigy 130 points

Part Number: CC3220SF-LAUNCHXL
Other Parts Discussed in Thread: CC3220SF

Tool/software: Code Composer Studio

Hello 

I am facing problem while interacting with the UMTS&LTE EVB_V2.2 .

Firstly, I sent "AT/r" to the EVB directly through terminal it's responded with "OK\r\n"

Secondly,I sent "AT\r" to terminal through CC3220SF after programing it,I got the exact in the terminal window .

But,while sending the same to EVB through CC3220SF with same baud rate(115200) and settings(1 stop bit ,flow_control =None,read/write mode=binary) I am not getting any response 

So,Could anyone please suggest me any possible errors that I can rectify to make it work with CC3220SF.  

  • 0
    TI__Mastermind 40965 points

    Hi,

    Does the LTE EVB use the same 3V3 logic as the CC3220? If not, you will need level shifters to change the voltage of the UART signal from the CC3220 as appropriate.

    Are you able to use a logic analyzer to capture the UART signals between the CC3220 and the LTE EVB? That will allow you to see if the "AT\r" is sent correctly, if there is some response that comes out of the LTE EVB that is simply missed by the CC3220, as well as other potential issues with the physical connection.

    Regards,

    Michael

  • 0 in reply to Michael Reymond
    Prodigy 130 points

    Hi Michael,

    Thanks for your quick response But, as I can receive the signal into CC3220SF from the EVB when sending AT\r through the terminal So, I think level shifters are not required and I verified the signal sent by CC3220SF it's correct and intact.

  • 0 in reply to Rupam Biswas
    TI__Mastermind 40965 points

    Hi,

    How are you sending and receiving the UART signal on the CC3220? Are you using a modified example from the SDK? If you could please provide a code snippet showing how you are performing your UART communication that would be useful for debug.

    Also, if you could provide a block diagram of how you are testing the system that would be helpful for me to understand the tests you are running. When you say that you are sending the "AT\r" string to the EVB through the CC3220, do you mean that the CC3220 code sends this string to the EVB without PC terminal interaction using the UART0 interface? Or do you have your PC connected to the CC3220 on UART0, and using the CC3220 to relay commands and UART data to the LTE EVB on UART1?

    Regards,

    Michael

  • 0 in reply to Michael Reymond
    Prodigy 130 points

    Hi,

    Sorry for the bad Hand-Writing, Hope you can understand the attached image below.

  • 0 in reply to Rupam Biswas
    TI__Mastermind 40965 points

    Hi,

    Thanks for drawing that diagram. Your setup is much clearer to me now.

    How are you wiring the CC3220SF to the PC terminal for case-3? Are you using the onboard XDS110 debugger as the UART to USB bridge, or are you using a separate UART to USB device?

    If you are using the XDS110, how are you routing the TX output to the EVB? Are you removing the J5,J6 jumpers, or are you doing something else?

    For case-1, how are you seeing the RX data from the EVB? Do you relay the received data back to the PC for display? 

    Regards,
    Michael

  • 0 in reply to Michael Reymond
    Prodigy 130 points

    Hi,

    Yes, I am using the onboard XDS110 debugger as the UART to USB bridge.

    Yes, I am routing the TX output to the EVB  by removing the J5, J6 jumpers.

    In case-1, I am seeing the RX data from the EVB in my code through debugging it.

    When I got an interrupt for received bytes from UART then I checked the receive buffer, there I looked for the received data from EVB.

  • 0 in reply to Rupam Biswas
    TI__Mastermind 40965 points

    Hi,

    When you are connecting the CC3220 UART to the EVB, are you connecting through the CC3220 launchpad headers, or are you connecting directly to the J5 J6 header? If you are connecting to the CC3220 launchpad headers, then you will need to actually keep jumpers on J5 and J6, just on the pin 2:3 position (in line with the rest of the jumpers). 

    Regards,

    Michael

  • 0 in reply to Michael Reymond
    Prodigy 130 points

    Hello Michael,

    Thanks a lot for your support and suggestions.

    But, I would like to know the reason behind it.

    And if the situation is like, I want to use A1 UART base then also I have to connect the J5 and J6 headers??