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Issue with ADS1290 .....

Sandeep Sharma46
Prodigy 60 points
Other Parts Discussed in Thread: ADS1292, MSP430F5529, ADS1292ECG-FE

Hi,

I am facing a issue with ADS1290 interfacing via SPI with MSP430. I am measuring the 4-20 mA current input on channel 2 and configuring the ADS1290 via SPI. I am able to read/write all configuration registers with successfully. MSP is running on 8 Mhz and SPI is using SMCLK.

I am getting aprox half of the ADC count from ADS1290 via SPI e.g. for 0.4 V measuring count is equivalent to 0.22V and for 2.0 V measuring count is equivalent to 1.1 V.

Using Vref 2.44 V internal and using formula to convert counts to Volts = 2.42 / (2^23 - 1).

Could you please help me to resolve this issue?

Following are the registers setting:

ADS1292_Default_Register_Settings[12] =

{

 

                //REG 0: Device ID read Ony

                0x53,

 

                //REG 1: CONFIG1

                0x02,                                       // 010       |               fMOD/256                                               |               500SPS

 

                //REG 2: CONFIG2

                0xE8,                                      // Bit 7 always 1, PDB_LOFF_COMP, PDB_REFBUF, CLKOUT_EN

 

                //REG 3: LOFF

                0x10,                                      // Comparator threshold at 95% and 5%, current source or sink resistor DC lead-off

 

                //REG 4: CH1SET (PGA gain = 6)

                0x81,                      // Power down, input shorted, Channel 1 not in use   2 June

 

                //REG 5: CH2SET (PGA gain = 6)

                0x10,                      // gain set to 1

 

                //REG 6: RLD_SENS (default)

                0x2C,

 

                //REG 7: LOFF_SENS (default)

                0x0F,                      // not required

 

                //REG 8: LOFF_STAT

                0x48,                      // read only

 

                //REG 9: RESP1

                0xEA,                     // not required

 

                //REG 10: RESP2

                0x83,                      // only Calib set to Enabled , rest not required

 

                //REG 11: GPIO

                0x0C                       // not required

};

Regards,

Sandeep

  • 0
    TI__Mastermind 32475 points
    I don't think this is a TIRTOS issue. I'm going to recommend this thread be moved to a MSP43x specific forum.
  • 0 in reply to judahvang
    TI__Guru* 96960 points
    I've moved your thread to the device forum.

    Todd
  • 0
    TI__Guru**** 202106 points
    Hi Sandeep,

    Which MSP430 device derivative are you using? Please provide your ADC initialization, read, and conversion code. Any debugger screenshots further describing the issue you are noticing would be appreciated as well.

    Regards,
    Ryan
  • 0 in reply to Ryan Brown1
    TI__Genius 16740 points

    In addition to Ryan's comments:

    Please make sure you are using the right configuration of the SPI (polarity/phase in UCBxCTLW0). 

    The ADS1292ECG-FE includes code for the MSP430F5529 (you need to install the whole software package); perhaps you use that code as a reference/guide. Based on that code, I can see the following configuration:

      UCB0CTL0 |= UCMSB+UCMST+UCSYNC;			//[b0]   1 -  Synchronous mode 
							//[b2-1] 00-  3-pin SPI
							//[b3]   1 -  Master mode
							//[b4]   0 - 8-bit data
							//[b5]   1 - MSB first
							//[b6]   0 - Clock polarity low.
							//[b7]   1 - Clock phase - Data is captured on the first UCLK edge and changed on the following edge.

    With your current configuration, can you read the ID register properly, or can you read the default configuration of all the other registers?

    If you get incorrect data, then this could be a problem with the MCU configuration. If you get the right data, then this could be a problem with the ADS configuration (either in hardware or registers), and the their team is probably better equipped to help you.

    Regards,

    Luis R

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