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ADS8910B: SPI usage

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Part Number: ADS8910B

Do we have any application notes about the usage of SPI interface in ADS8910B?

My MSP432/C2000 SPI is byte bound. In other words, I only can read 1 bytes at a time. I could not read 18 bit at a time. So, I guess I will have to read 3 bytes from ADS and throw away the last 6 bits. And the MCU will hold the CS line LOW for the entire 3 bytes reading period. Will this way work? Will this affect the other register bits inside ADS? 

Thanks

Wen

  • Hello Wen,

    This app note provides the best overview for the Enhanced SPI on the ADS8910B.

    http://www.ti.com/lit/wp/sbay002/sbay002.pdf

    Please note that section 2.2 in the app note talks about  Silent Zones for data transfer.  The ADS8910B only requires that the blue zone be observed.  As shown in Figure 44 of the datasheet, the red zone discussed in the app note does not apply to this device.

    You can send as many SCLK's as necessary in a data frame.  When you just need to read the conversion result, you can hold the DIN line low for the entire data transfer frame (NOP command).  If you are sending a different command using a 24b frame, you would want to pad the first two bits with 0, followed by the 22b command.

    Section 7.5.2 in the datasheet discusses this in more detail.

    Thanks,
    Keith Nicholas
    Precision ADC Applications