AD7683 and Sampling clock

Hi,

I need to know how to vary the sampling frequency of AD7683?

It is written that the sampling clock is internal.

I need to use this for 1KHz and 256Hz sampling,is this possible?

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  • Hi,

    What it means is that I can not sample the ADC continuously !

    What I understood from you is DCLOCK is the one which decides the sampling.

    Is this correct?I mean DCLOCK can go in MHz (1.2MHz) how it will work then?

    Usually it is some down conversion of DCLOCK can sample this.

    This is good for Single Shot mode.

    I have few questions

    1.It means that Micro Controller's SPI will be continuously busy by giving the clock at desired sampling rate.

    2.We can not put anything else on that SPI as the clock will be too slow

    3.Aperture Jitter will be there as the sampling clock is derived from DCLOCK.

    4.What is the use of internal clock mentioned at the start of the Datasheet.

    5.Is there any EOC ?to interrupt the DSP?

    Pls keep this thread alive !

    Usually the SPI clock is just for reading the Sampled data.It can be of any value and periodically DSP will read it by giving a high clock data quickly so that it can use the SPI bus for other ADCs or devices.Sampling is done by an internal or external clock with or without PLLs,results are just made ready in the SPI buffer to read.

    Pls comment in the point of contiuous reading of the ADC ,probably with a seperate crystal.

Reply
  • Hi,

    What it means is that I can not sample the ADC continuously !

    What I understood from you is DCLOCK is the one which decides the sampling.

    Is this correct?I mean DCLOCK can go in MHz (1.2MHz) how it will work then?

    Usually it is some down conversion of DCLOCK can sample this.

    This is good for Single Shot mode.

    I have few questions

    1.It means that Micro Controller's SPI will be continuously busy by giving the clock at desired sampling rate.

    2.We can not put anything else on that SPI as the clock will be too slow

    3.Aperture Jitter will be there as the sampling clock is derived from DCLOCK.

    4.What is the use of internal clock mentioned at the start of the Datasheet.

    5.Is there any EOC ?to interrupt the DSP?

    Pls keep this thread alive !

    Usually the SPI clock is just for reading the Sampled data.It can be of any value and periodically DSP will read it by giving a high clock data quickly so that it can use the SPI bus for other ADCs or devices.Sampling is done by an internal or external clock with or without PLLs,results are just made ready in the SPI buffer to read.

    Pls comment in the point of contiuous reading of the ADC ,probably with a seperate crystal.

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