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MSP430F6736: external ADC interfacing

Keval Desai
Intellectual 590 points

Part Number: MSP430F6736
Other Parts Discussed in Thread: ADS1231, MSP430WARE

Hello guys,

I want to interface an external ADC with MSP430F6736 micro-controller. 

The external ADC I am using is ADS1231 (24-bit ADC). I will feed analog data to the ADC and I want to read the data to the micro-controller.

What steps do I need to follow?

Thank you.

  • 0
    Guru 103135 points
    This is an SPI device, so start by reading through the SPI ("usci_spi") examples for your MCU. I don't see any Chip Select (/CS) nor Master Out (SIMO), so you'll connect only SCLK and SOMI.

    When the time comes (see below) transmit 3 "dummy" bytes; the bytes you receive back will be your data (most-significant-byte first).

    "The time comes" when DRDY (which is also DOUT/SOMI) goes low between readings. One headache you should anticipate is the "25th clock" (data sheet SBAS414D p.13) which in effect "releases" DOUT to become DRDY. Sending 1 bit with the SPI isn't easy. On the other hand, you Might be able to send 8 more bits (clocks), rather than just 1, without the device caring about it -- the data sheet doesn't say.

    Also search the Forum. Without looking very hard, I found:
    e2e.ti.com/.../635377
  • 0
    TI__Genius 10860 points

    Hi,

    I can second what Bruce suggested for you. With respect to the code examples: You'll find some code examples wihtin the MSP430Ware, those provide both code for a SPI master configuration as well as a SPI slave configuration.

    Also, have a look at the MSP430x5xx and MSP430x6xx Family User's Guide Chapter 37 on the Universal Serial Communication Interface in SPI mode. This will help you to understand how the module works and how to configure it to your needs.

    Another helpful document could be the Solutions to Common eUSCI and USCI Serial Communication Issues on MSP430 MCUs application report.

    Please let us know in case there are still pending questions after going through the material.

    Best regards,

    Britta

  • 0 in reply to Britta Ruelander
    Intellectual 590 points
    Thank you for the help.
    I'll get back to you once I go through the material and test it.

    Thank you.
    Appreciate it.
  • 0 in reply to Keval Desai
    TI__Genius 10860 points
    Hi,

    as I didn't hear back from you in a while I assume that your issue has been solved.
    Please go ahead and verify the given answer to also help other users that might run into the same issue.

    Note that I'll go ahead and close this thread in the next couple of days if I don't hear back from you. Replying to the thread will re-open it if necessary at some point.

    Best regards,
    Britta

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