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Regarding ADC capture

vijayabharathi chelladurai
Intellectual 955 points
Other Parts Discussed in Thread: ADS8364Hi Currently in our new design, we are using the 16 bit parallel ADC "ADS8364" for data acquistion. ADC output supposed to be connected to OMAP L138 EMIF. OMAP should read the 16 bit ADC output and write in the SATA in the other side.ADC sampling rate is 200KHz ie 5uS once the data will be present We are planning to devolp software in sense of copying the ADC output to a buffer(ping pong), then transfer to the SATA using EDMA?as well as we plan to use linux Kindly confirm me timing problem should not come while doing this data transfer ie Is this approach will cause loss of any samples. 1. Is it possible to use DMA for EMIF in the ADC capture side, as the ADC have SOC,EOC signals? 2. Is it possible to connect 16 bit ADC output with a GPIO bank for capture instead of EMIF? will the performance be affected because of slow operation of GPIO Regards Vijayabharathi C
  • 0
    TI__Genius 14545 points

    Vijayabharathi,

    vijayabharathi chelladurai said:
    1. Is it possible to use DMA for EMIF in the ADC capture side, as the ADC have SOC,EOC signals?

    I'm not familiar with the ADS8364 or the abbrevitations SOC, EOC. Can you clarify what these mean?

     

    vijayabharathi chelladurai said:
    Is it possible to connect 16 bit ADC output with a GPIO bank for capture instead of EMIF?

    Have you referenced the OMAP-L138 Universal Parallel Port (uPP) peripheral?  This might be exactly what you are looking for.

  • 0 in reply to dabuan
    Intellectual 955 points

    Hi Drew

     

    Thanks for the reply.

     

    >>I'm not familiar with the ADS8364 or the abbrevitations SOC, EOC. Can you clarify what these mean?

    SOC - Start of conversion. There is a signal in the ADC Chip namely Hold which has to be made lo for min 20 ns and then made high.

    EOC -End of conversion  This is interrupt to the processor,,so that processor will identify that conversion in ADC finished, and processor will read after acquitstion time

    So i think some need for hardware circuitry to control automatically, when processor reads automatically through DMA? Is my understanding correct. KIndly advise me

     

    In my application i have 3 channel input, which is simultaneous sampled by the above ADC and digital value will be captured by the processor, written in SATA in some structure. We are planning to operate this ADC in  FIFO mode . KIndly advise us

    We will check the uPP regarding the use

     

    Regards

    Vijayabharathi C

     

  • 0 in reply to vijayabharathi chelladurai
    TI__Genius 14545 points

    Thanks.

    vijayabharathi chelladurai said:
    So i think some need for hardware circuitry to control automatically, when processor reads automatically through DMA? Is my understanding correct.

     

    It certainly sounds like the ADS8364 needs some hardward signals to interface to, however the ADS8364 datasheet should provide you with details of all the signals needed to work with a processors. The uPP has an integrated DMA that can be used to transfer the captured data into memory. The device has a good number of GPIO's that can be used to interface to the ADC.

     

    vijayabharathi chelladurai said:
    In my application i have 3 channel input, which is simultaneous sampled by the above ADC and digital value will be captured by the processor, written in SATA in some structure. We are planning to operate this ADC in  FIFO mode . KIndly advise us

    This sounds like a typical use case, however it would be best to ask questions on the  specifics of the ADC in the Data Converters Forum as they are the experts as the use case of the ADC.