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ADC over serial (12 bits, 4 input lines)

Other Parts Discussed in Thread: TLV2544, ADS1015, ADS1115

Good afternoon - hopefully this isn't too tricky of a question:

We desire a 4-input 12-bit ADC controllable entirely over three-wire serial communication (RxD, TxD, GND):

  • Input voltage will be no greater than 0.7 V.
  • Positive voltage rails available at 1.5 V, 3 V, 4.5 V, and 6 V (tapping off a battery pack.)

Currently trying to determine if the TLV2544 is appropriate.  Any input appreciated.

Best,
Adam V.
U of Saskatchewan

  • Hi Adam,

    The TLV2544 needs four control lines - it's /CS input has to toggle and you need a serial clock along with TX and RX data.  Is your RxD, TxD and GND essentially an RS232 port or is this a simple 3-wire SPI interface?  What is your host controller?  Have you looked at the internal ADC of the MSP430 family of micros?

  • Hi Tom,

    Thanks kindly for your reply.  We've been looking at the TLV2544 closer and you are correct, we need control of /CS and a serial clock.

    We are using a GumStix microcontroller and unfortunately do not have an option to switch to the MSP430 family.  The GumStix has an onboard ADC but after weeks of attempting to access it we are seeking an external solution.

    The RxD, TxD, and GND are accessible as serial ports on the micro via a UART interface.  In the past, RS232 was used successfully with these ports.  The board also has an option to use an I2C interface, but we are less familiar with that.

    I hope the above was clear, we are learning as we go and appreciate the help.

    Best regards,
    Adam

  • Hi Adam,

    There are no asynchronous 'UART' type serial interface devices within our portfolio that I am aware of.  We do have a number of devices that have an I2C interface though.  Try taking a look at the ADS1015 or ADS1115, they may suit your needs.

  • Hi Tom,

    Thank you for your help - we have been looking at the ADS1015 and will continue to determine whether our micro can handle the I2C interface.

    Thanks again,
    Adam V.