CCS/LAUNCHXL-CC3235S: Unable to send data over UART (cc3235s as master) to slave (works on rs232).

Hi Sarju,

The initialization code looks fine. Running that on my end results in the UART interface being setup and opened correctly. That being said, if you are using a readCallback, please also set the readMode as UART_MODE_CALLBACK. Without that set, you will not get returned data to your callback.

Running your provided sample code also seems to result in the expected behavior occurring.Have you ensured you performed a UART_read() with callback mode enabled?

Have you also checked the UART signals with a logic analyzer to ensure that the TX signals are getting to the slave correctly, and that it is sending back the expected response?

Regards,

Michael

Hi Michael,

Thanks for reply, at this stage i am able to send command to slave and it's changing it's state accordingly. and it should send back response packet of 28 byte. 

but, i am not able to get that packet.

in short my callback function is not getting call ever. i did the changes as you said. have a look..

 UART_init();

        /* Create a UART with data processing off. */
        UART_Params_init(&uartParams);

        uartParams.writeDataMode = UART_DATA_BINARY;
        uartParams.readDataMode = UART_DATA_BINARY;
        uartParams.readReturnMode = UART_RETURN_FULL;
        uartParams.readMode=UART_MODE_CALLBACK;
        uartParams.readCallback=(UART_Callback)readCallback;
//        uartParams.readEcho = UART_ECHO_OFF;
        uartParams.dataLength = UART_LEN_8;
        uartParams.stopBits = UART_STOP_ONE;
        uartParams.parityType = UART_PAR_NONE;
        uartParams.baudRate = 9600;

        uart = UART_open(CONFIG_UART_0, &uartParams);
        uart2 = UART_open(CONFIG_UART_1, &uartParams);

        if (uart2 == NULL)
        {
            /* UART_open() failed */
            while (1)
                ;
        }
        if (uart == NULL)
        {
           /* UART_open() failed */
           while (1)
               ;
        }

and here is my callback function

static void readCallback(UART_Handle handle, void *buffer, size_t size)
{
        UART_write(uart2, echoPrompt, sizeof(echoPrompt));

//    UART_read(uart2, receivedDataPacket, sizeof(receivedDataPacket));
    if(0xFF==(*(uint8_t*)buffer))
    {
        if(size==28)
        {
//            ddress_h = ((uint8_t*)buffer)[1];
//            address_l = ((uint8_t*)buffer)[2];
//            cmd = ((uint8_t*)buffer)[3];
//            data = ((uint8_t*)buffer)[4];
//            checksum = ((uint8_t*)buffer)[5];
            UART_read(uart2, receivedDataPacket, sizeof(receivedDataPacket));
        }
        else // size will always be 28 so this is unneccessary
        {
            UART_readCancel(uart2);
        }
    }
    else
    {
        UART_readCancel(uart2);
    }
//    i=0;
//    while(i<sizeof(receivedDataPacket))
//    {
//        UART_write(uart2, &receivedDataPacket[i], sizeof(receivedDataPacket[i]));
//        i++;
//    }

//    UART_write(uart2, receivedDataPacket, sizeof(receivedDataPacket));

}

this function is not getting call ever.

every time whenever i am running my program , this is what i am getting on the terminal windows.

and slave is changing it's stage immediately, which is good as expected. it means i am able to send data(command), but not able to receive.

please help me to get rid from this problem.

thank you so much for your reply once again.

waiting for your response further...

Br,

sarju bhatnagar

Hi Sarju,

Do you perform a UART_read() call in your application after you write the data to the slave?

As you can see in the original example, you need to perform a UART_read(), and provide an input buffer as well as a total read size before the UART interface will read any data. If you perform a UART_read() in your code after sending the command data do you get the expected data back?

Reworking your code, it should look something like this:

void* mainThread(void *arg0)
{
    uint8_t input;

    const char echoPrompt[] = "Echoing characters from uart:\r\n";
    const char echoPrompt2[] = "Echoing characters from uart2:\r\n";
    UART_Params uartParams;

    /* Call driver init functions */
    GPIO_init();

    switch (interanlLIB_or_externaLIB)
    {
    case INTERNAL_LIBRARY:
        UART_init();

        /* Create a UART with data processing off. */
        UART_Params_init(&uartParams);

        uartParams.writeDataMode = UART_DATA_BINARY;
        uartParams.readDataMode = UART_DATA_BINARY;
        uartParams.readReturnMode = UART_RETURN_FULL;
        uartParams.readCallback=(UART_Callback)readCallback;
//        uartParams.readEcho = UART_ECHO_OFF;
        uartParams.dataLength = UART_LEN_8;
        uartParams.stopBits = UART_STOP_ONE;
        uartParams.parityType = UART_PAR_NONE;
        uartParams.baudRate = 115200;

        uart = UART_open(CONFIG_UART_0, &uartParams);
        uart2 = UART_open(CONFIG_UART_1, &uartParams);

        if (uart2 == NULL)
        {
            /* UART_open() failed */
            while (1)
                ;
        }
        if (uart == NULL)
        {
           /* UART_open() failed */
           while (1)
               ;
        }

        UART_write(uart, echoPrompt, sizeof(echoPrompt));
        UART_write(uart2, echoPrompt2, sizeof(echoPrompt2));
        break;
    case EXTERNAL_LIBRARY:
        InitTerm();
        UART_PRINT("Echoing characters:---\r\n");
        break;
    };

    /* Configure the LED pin */
    GPIO_setConfig(CONFIG_GPIO_LED_0, GPIO_CFG_OUT_STD | GPIO_CFG_OUT_LOW);

    /* Turn on user LED */
    GPIO_write(CONFIG_GPIO_LED_0, CONFIG_GPIO_LED_ON);

    memset((void*) receivedDataPacket, 0, sizeof(receivedDataPacket));

//    sendData();
   setData();
   UART_read(uart2,receivedDataPacket,sizeof(receivedDataPacket));
//    while (1)
//    {
//        usleep(20000);
//        UART_read(uart2, &input, sizeof(input));
//        UART_write(uart2, &input, sizeof(input));
//    }
}


static void readCallback(UART_Handle handle, void *buffer, size_t size)
{
    if(0xFF==(*(uint8_t*)buffer))
    {
        if(size==28)
        {
//            ddress_h = ((uint8_t*)buffer)[1];
//            address_l = ((uint8_t*)buffer)[2];
//            cmd = ((uint8_t*)buffer)[3];
//            data = ((uint8_t*)buffer)[4];
//            checksum = ((uint8_t*)buffer)[5];
            //Signal to application here through a semaphore/mutex/message queue that data is ready
        }
        else // size will always be 28 so this is unneccessary
        {
            //Error state, didn't get correct data from slave
            //UART_readCancel(uart2);
        }
    }
    else
   {
       //UART_readCancel(uart2);
   }

}

Regards,
Michael

Hi Michael,

you: you need to perform a UART_read()

Yes i tried this as well see this

 setData();
    usleep(20000);
    SendToGetStatusRespFromRect2(getStatusFromRect2Packet, sizeof(getStatusFromRect2Packet));
    usleep(20000);
    UART_read(uart2, receivedDataPacket, sizeof(receivedDataPacket));

setData(); functions is able to send the data and salve changes its state. so i can say communication is established.

secondly.

SendToGetStatusRespFromRect2(getStatusFromRect2Packet, sizeof(getStatusFromRect2Packet));

is to get response back from slave.

UART_read(uart2, receivedDataPacket, sizeof(receivedDataPacket)); is the function which used to receive data.

Ques: I need to use only UART_read(uart2, receivedDataPacket, sizeof(receivedDataPacket)); to receive data, but what about to print data on the terminal screen.Ques: when readCallback function will be called?should i use UART_write(uart2, receivedDataPacket, sizeof(receivedDataPacket));inside readcallback function print the data on terminal screen.i tried many ways to get data over uart

1:
setData();
    usleep(20000);
    SendToGetStatusRespFromRect2(getStatusFromRect2Packet, sizeof(getStatusFromRect2Packet));
    usleep(20000);
   // UART_read(uart2, receivedDataPacket, sizeof(receivedDataPacket));
    usleep(20000);

    while(UART_readPolling(uart2, receivedDataPacket, sizeof(receivedDataPacket))!='\0');
    {
      //  i=0;
     //   while(i<sizeof(receivedDataPacket))
       // {
            UART_write(uart2, receivedDataPacket, sizeof(receivedDataPacket));
         //   i++;
       // }
    }

2:

 setData();
    usleep(20000);
    SendToGetStatusRespFromRect2(getStatusFromRect2Packet, sizeof(getStatusFromRect2Packet));
    usleep(20000);
    UART_read(uart2, receivedDataPacket, sizeof(receivedDataPacket));
    usleep(20000);

//    while(UART_readPolling(uart2, &receivedDataPacket, sizeof(receivedDataPacket))!='\0');
//    {
        i=0;
        while(i<sizeof(receivedDataPacket))
        {
            UART_write(uart2, &receivedDataPacket[i], sizeof(receivedDataPacket[i]));
            i++;
        }

3:

 setData();
    usleep(20000);
    SendToGetStatusRespFromRect2(getStatusFromRect2Packet, sizeof(getStatusFromRect2Packet));
    usleep(20000);
//    UART_read(uart2, receivedDataPacket, sizeof(receivedDataPacket));
    UART_readPolling(uart2, &receivedDataPacket, sizeof(receivedDataPacket));
    usleep(20000);

//    while(UART_readPolling(uart2, &receivedDataPacket, sizeof(receivedDataPacket))!='\0');
//    {
        i=0;
        while(i<sizeof(receivedDataPacket))
        {
            UART_write(uart2, &receivedDataPacket[i], sizeof(receivedDataPacket[i]));
            i++;
        }
//    }

but, not able to get data.

please do let me know what else should i try?

Thanks,

sarju bhatnagar

Dear Team,

Waiting for reply?

thanks

sarju

this time i am able to send data to UART0 using pin03 and p04 , 

but as i mentioned above i want to talk to two uart slaves at the same time, in short i want to take data from one uart that is uart0 and same data i want to show to another slave(display) through uart1 . 

but i am unable to show the data on slave(display) through uart1.

how can i use another UART1 on pin55(tx/gp01) and pin57(rx/gp02), please do let me know?

thanks

sarju

Hi Sarju,

I made a simple test program based on the uartecho SDK example to test uart0 + uart1 echo functionality much like what you're trying to do by reading data from slave 0 and passing it to slave 1 and everything works as expected.

I have this code using p55/57 as UART0 through the XDS110 launchpad debugger, as well as p3/4 for UART1 through an FTDI UART to USB adaptor, and I have verified that the functionality works correctly on my CC3235 launchpad.

The example code is attached here, simply import the uartecho project and overwrite the existing uartecho.c with this code: /cfs-file/__key/communityserver-discussions-components-files/968/uartecho2.c

Please use that code as an example of how to have two UART peripherals passing data to each other, and I advise you either to base your UART communication code off of my example or to carefully compare your UART code with the working code provided and debug the changes needed.

Regards,

Michael