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ADS1247EVM: Migration to TIPD120

Harikrishnan R S
Expert 1670 points

Part Number: ADS1247EVM

Hi,

I am currently working with the ADS1247 EVM for an RTD measurement application.

  1. I have modified the EVM circuit with reference of TIPD120 Design files and the modifications done are attached.
  2. When I try to read the Analog input, the ADS1247 always returns with zero.
  3. Differential voltage between AIN1 and AIN2 was measured and noted as 110 mV
  4. Reference Voltage between REF0P and REF0N was measured and noted as 1.6 V

  5. The data is polled using the status of DRDY pin.
  6. The following register settings was used for configuration.

     Address        Register       Value

00h            MUX0            0A
01h            VBIAS           00
02h            MUX1            20
03h            SYS0             22
04h            OFC0             00
05h            OFC1             00
06h            OFC2             00
07h            FSC0             00
08h            FSC1             00
09h            FSC2             00
0Ah            IDAC0           96
0Bh            IDAC1           03
0Ch            GPIOCFG     00
0Dh            GPIODIR      00
0Eh            GPIODAT      00

 

Thank you in advance for any help you provide.

 

ADC - RTD.pdf

  • 0
    TI__Guru 51471 points

    Hi Harikrishnan,

    Thanks for your post! 

    Can you provide screenshots of the attempted serial communication showing SCLK, DOUT, CS, and DIN?

    What method is being used to clock data out of the device? Is the device in RDATAC or SDATAC mode? 

  • 0 in reply to Alexander Smith
    Expert 1670 points

    Hi Alex,

    Thanks for the reply.

    The issue was solved. The errors that occurred while reading the ADC data was due to the misconfiguration of the  ADC registers.

    I was writing to the registers with a single WREG command followed by MUX0 Register address and 0x0E (number of registers to be updated). Thereby updating the registers MUX0, MUX1, SYS0, IDAC0 and IDAC1 with the reference values and other registers with zero.

    While doing this, the FSC0, FSC1 and FSC2 registers were also modified. This Resets the Gain Calibration to zero.

    Now I write only to the required registers.