ADS131M02: ADC

Hi ABI BHARATHI,

The example code in the following link can be a good start for you. 

SBAC254 — ADS131M0x Example C Code

Also, please check the details in the session of 8.5.1.7 SPI Communication Frames in ADS131M02 datasheet. The following figure is a typical SPI timing for this ADC, you can monitor /DRDY signal or use that signal as an interrupt to your AM243x processor, the falling edge of /DRDY indicates that the data is ready to read, then you can send RREG, WREG command to read or write registers, or just send send out SCLK clocks by sending enough 0 data (NULL) to retrieve conversion data from the ADC via SPI interface.

Regards,

Dale

Hi Dale li,

Thankyou for your valuable response..

In a weighing application, an ADS1235 (Analog-to-Digital Converter) and a 1022 load cell are used. However, at first, we have an ADC 15 click driver module itself  ADS131M02 and we need to figure out how to collect data with that ADC in SPI interface, including ADC configuration, calibration, and filtering.

You prefer that link ads131m02 code is a MSP430 controller but we work with that AM243x launchpad

we still need your help on how to interpret the analogue data.

Thankyou,

Abinaya

Hi ABI BHARATHI,

This is C code, it should be able to be used for other processor with some modifications. This is the only example code we have for ADS131M0x. As I said, you can also check the timing and the details in ADS131M02 datasheet, I can help you if you have any trouble to collect the data form the ADC.

Regards,

Dale

Hi Dale Li,

Thanks a lot for your help!

Yes, I made changes to that c code in AM243x Launchpad, but I'm not sure where the adc data is supposed to be received in that function.  

This is modified c file in ads131m0x 

...  

Hi ABI BHARATHI,

The example code has a detailed description and explanation for each function and most code lines. I hope you can check the details first.

The function to read conversion data is "readData(adc_channel_data *DataStruct)" in ads131m0x.c file, you have to call this function in your main program. However, you have to check if the flag of "flag_nDRDY_INTERRUPT" is true in your main program loop before you call  "readData(adc_channel_data *DataStruct)" function to read data. The flag of "flag_nDRDY_INTERRUPT" is set to "True" when the /DRDY signal triggers the interrupt and the "void GPIO_DRDY_IRQHandler()" interrupt routine is executed in hal.c file. 

There is another alternative solution to read data, you can call "readData(adc_channel_data *DataStruct)" function in the "void GPIO_DRDY_IRQHandler()" interrupt routine in hal.c file instead of calling it in your main program loop.

I also strongly recommend you to check README file which has already shown how to use this example code step by step:

Hi Dale Li,

Thank you, sorry for the delayed response.

Yes, I checked the flag of "flag_nDRDY_INTERRUPT" is true in the main programme loop when I use the "readData(adc_channel_data *DataStruct)" function to read data, however in that debugging session didn't go with that flag, it exited with that function.

Thanks & Regards,

Abinaya

Hi ABI BHARATHI,

Dale is out of the office right now, he will respond to later this week

However, if you have trouble with your serial communication, please send us clearly-labeled logic analyzer or scope shots of your communication so we can help diagnose issues.

-Bryan

Hi Bryan,

Thankyou for your response...

uint8_t spiSendReceiveByte(const uint8_t dataTx)
{
    /*  --- INSERT YOUR CODE HERE ---
     *  This function should send and receive single bytes over the SPI.
     *  NOTE: This function does not control the /CS pin to allow for
     *  more programming flexibility.
     */

    // Remove any residual or old data from the receive FIFO
    uint32_t junk;
    while (SSIDataGetNonBlocking(SSI_BASE_ADDR, &junk));

    // SSI TX & RX
    uint8_t dataRx;
    MAP_SSIDataPut(SSI_BASE_ADDR, (uint32_t) dataTx);
    MAP_SSIDataGet(SSI_BASE_ADDR, (uint32_t *) &dataRx);
 
    return dataRx;
}

The preceding code has a msp430 driver library...How to rebuild this function in Am243x Launchpad? 

Thanks 

Abinaya

Hi ABI BHARATHI,

If you have questions about porting code from one MCU to another, please post that question in the "Microcontrollers" forum and one of our experts will assist you

-Bryan

Hi Bryan,

Ok, Thankyou for your suggestion.

Regards,

Abinaya

Hi,

I am refer that AM243x MCU+ SDK example:mcspi_loopback_am243x-lp_r5fss0-0_nortos_ti-arm-clang. The McSPI instance initialization/open code is generated based on the example.syscfg by syscfg automatically. but I am using MCU_PLUS_SDK_AM243x_09.00.00.30, yet the mcspi driver source file only contains this mcspi transfer function (int32_t MCSPI_transfer(MCSPI_Handle handle, MCSPI_Transaction *transaction).

The SPI write and read functions are not provided...How to send the adc register and receive data?

Thanks,

Abinaya

Hi,

I am refer that AM243x MCU+ SDK example:mcspi_loopback_am243x-lp_r5fss0-0_nortos_ti-arm-clang. The McSPI instance initialization/open code is generated based on the example.syscfg by syscfg automatically. but I am using MCU_PLUS_SDK_AM243x_09.00.00.30, yet the mcspi driver source file only contains this mcspi transfer function (int32_t MCSPI_transfer(MCSPI_Handle handle, MCSPI_Transaction *transaction).

The SPI write and read functions are not provided...How to send the adc register and receive data?

bool readData(adc_channel_data *DataStruct)
{


    uint8_t dataRx[4] = {0};
    //uint8_t bytesPerWord = getWordByteLength();
    /* Set the nCS pin LOW */
    setCS(LOW);

    // Send NULL word, receive response word
    int i;
    dataRx[i] = spiSendReceiveByte(0xA5);

    DataStruct->response = combineBytes(dataRx[0], dataRx[1]);

       // Send 2nd word, receive channel 1 data
     dataRx[i] = spiSendReceiveByte(0x14);

     DataStruct->channel1 = signExtend(&dataRx[0]);

#if (CHANNEL_COUNT > 1)

    // Send 3rd word, receive channel 2 data

        dataRx[i] = spiSendReceiveByte(0x11);
        DataStruct->channel2 = signExtend(&dataRx[0]);


#endif

    /* Set the nCS pin HIGH */
    setCS(HIGH);

    // Returns true when a CRC error occurs
    return 0;
}


uint8_t spiSendReceiveByte( uint8_t dataTx)
{
  uint8_t dataRx;
  MCSPI_Transaction   spiTransaction;

  setCS(LOW);

       MCSPI_Transaction_init(&spiTransaction);
       spiTransaction.channel  = gConfigMcspi0ChCfg[0].chNum;
       spiTransaction.dataSize = 8;
       spiTransaction.csDisable = TRUE;
       spiTransaction.count    = (spiTransaction.dataSize/8);
       spiTransaction.txBuf    = (void *)dataTx;
       spiTransaction.rxBuf    = (void *)dataRx;
       spiTransaction.args     = NULL;

       DebugP_log("transmit data %d\r\n",dataTx);

       dataRx = MCSPI_transfer(gMcspiHandle[CONFIG_MCSPI0],&spiTransaction);
       DebugP_log("receive data %d\r\n",dataRx);


    setCS(HIGH);



    return dataRx;
}

In that preceding code is used in spi communication but that received data is 0. I need your help for solve that issue. 

Thanks,

Abinaya