AD7091R-8 read/write

Hello

Please let me know  below  about read/write of AD7091R-8

1:  I would like to read  conversion result of particular channel only  without use of sequencer.
Should I use the method  described in datasheet P.35  Figure 54. Channel Sequencer Multiple Channel Write ?

If there is any other method (for example, method without one latency ), please let me know your advice.

2:   When I transfer  read command to AD7091R-8   under sequence (  conversion of selected all channel is not completed ),

     is the result of read command returned at next cycle  after read command?

    Or is it returned at next cycle after sequence is completed ?

Regards,

Terumasa

  • 0
    •  Analog Employees 
    on Aug 8, 2014 12:15 AM

    Hi, Terumasa.

    Let me check on this. I'll get back to you soon.

    Regards,

    Karen

  • 0
    •  Analog Employees 
    on Aug 13, 2014 11:19 PM

    Hi, Terumasa.

    1. If you want to read the results from one channel, then you should only have the sequencer configured to operate on that single channel.  Set the channel register for only the channel of interest as seen in table 13 and table 14 of the datasheet.  If only one channel is enabled, the device will only produce results for that channel.

    2.  Can you clarify this question? What read command are you referring to - a conversion result read command or a register read command?

    Regards,

    Karen

  • Hi Karen,

    Sorro for late reply.

    1

    Thank you

    I understood this
    .

    2

    I woul like to know this about a register read command ( alert indication).

    Datasheet P.26 says" if a conversion happens in the meantime, the conversion result is sent instead of the alert indication register content".

    Then I would like to know when the result of read command is returned.

    Regards,

    Terumasa

  • 0
    •  Analog Employees 
    on Sep 4, 2014 11:11 PM

    Hi, Terumasa.

    As discussed on the Reading Data from the Registers section of the datasheet, a conversion result always trumps a register read and is placed at the head of the line as seen in figure 51 on page 33.  Once the conversion result is read, any register read commands will take effect and additional clocks provided will clock out the register contents.  If the device is in sequencer mode, each convert start will convert a new channel in the sequence, but for each of those convert starts, a register read could also be associated with the conversion assuming no new convert starts come along.

    Hope this answers your second question.

    Regards,

    Karen