AD7091R-8

Hello
I'm trying to set up communication with AD7091R-8. In setup I send following SPI command: 0X0CFF, 0X08FF, 0XFFFF, 0XFFFF, 0X00FF. Then I periodically send 0X0020 and I'm trying to read channel 5. I'd like to read one channeland them sequential readings. I inserted pictures from the logic analyzer into the attachment. I guess I'm getting bad data. Could you help me.

Thank you

Lukáš Mistr

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  • 0
    •  Analog Employees 
    on Mar 13, 2018 5:56 AM

    Hi Mistr,

       Here is what I suggest you can try. After power up, make sure that to initialize the AD7091R-8 properly. Please refer to the Power On Device Initialization section of the datasheet.

       The AD7091R-8 default channel conversion is channel 0. a CONVST pulse initiate a conversion then followed by a /CS low after conversion time elapsed, to frame the conversion result of channel 0. If you want to convert another channel, channel 5 for example, you can write to the  0x0C20. This means you will write to the channel register to convert channel 5. There is latency of one conversion before the channel is updated. The channel 5 conversion result will be clocked out after two CONVST pulse.

    Regards,

    Jonathan

Reply
  • 0
    •  Analog Employees 
    on Mar 13, 2018 5:56 AM

    Hi Mistr,

       Here is what I suggest you can try. After power up, make sure that to initialize the AD7091R-8 properly. Please refer to the Power On Device Initialization section of the datasheet.

       The AD7091R-8 default channel conversion is channel 0. a CONVST pulse initiate a conversion then followed by a /CS low after conversion time elapsed, to frame the conversion result of channel 0. If you want to convert another channel, channel 5 for example, you can write to the  0x0C20. This means you will write to the channel register to convert channel 5. There is latency of one conversion before the channel is updated. The channel 5 conversion result will be clocked out after two CONVST pulse.

    Regards,

    Jonathan

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