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ADS8329 EOC NOT TOGGLE

reza jadidi
Prodigy 250 points
Other Parts Discussed in Thread: ADS8329, ADS7816

HI.

 I CONNECT ADS8329 TO LPC 1768 PINS.I CONNECT ADS8329 PIN CONVERSION TO OUTPUT GPIO

IF I CLEAR PIN FOR 200NS AND GO UP,EOC PIN OF ADS WHAT DO?

IF AFTER CONVERSION PIN GO LOW ADS8329 EOC(PIN 10) NOT GO DOWN ,WHAT MEAN?

ADS8329 IS CORRUPT??

MY ADS8329 PIN 10 NOT WORK IN THIS MANNER.PLEASE HELP FOR CORRECT MANNER.

 

SINCERELY

  • 0
    TI__Genius 9975 points

    Hello Reza,

    Could you please send digital logic analyzer captures of the ADS8329 interface? We need to see the signal in the the following six lines: SDO, FS/CS, SCLK, SDI, CONVST  and EOC/INT/CDI in order to understand what is going on.

    Thank you and best regards,

    Jose

  • 0 in reply to Jose Duenas
    TI__Genius 9975 points

    Hello Reza,

    I received your private message. My recommendation would be to carefully re-read the ADS8329 datasheet, paying special attention to pages 24 to 37.

    The EOC output goes LOW immediately following CONVST going LOW so a good approach upon start up would be to keep CONVST high, then issue a software reset and then start the conversion cycles.

    Hope this helps.

    Best regards,

    Jose

  • 0 in reply to Jose Duenas
    Prodigy 250 points
    THANKS JOSE.
    ABOUT ABOVE YOUR STATEMENT,YES I POWERD ADS8329 AND MICRO IN SAME TIME.IN SOFTWARE CONVST PIN IS UP AND FOR START CONVESION GO DOWN CONVST PIN FOR 100NS,AND UP.I EXPECTION IMMEDIATELY EOC GO DOWN AND AFTER ABOUT 18 CCLK EOC GO UP.

    MY SOURCE QUESTION AND DIFFICULT WAS THIS =WHEN POWERD ADS8329 PIN9=EOC STAY LOW(I EXPECTION GO UP)BUT SOME TIMES GO UP BUT NOT TRUE WORKS!!??
    I HAVE SOME QUESTIONS.(PLEASE GIVE ANSWER IN SIMPLE ENGLISH)
    IN DATASHEET CCLK MIN=21 AND MAX=24.5
    HOW CAN I KNOWN CCLK FREQUENCY FOR PRECISION TIMING?
    I WANT GET 20 SAMPLE IN 20US!

    IF IN+ SIGNAL GO UP 8V FOR 1US ADS8329 CORRUPT?
    I NEED Consultation FOR CONDITIONING FOR IN+ INPUT IN دثطف یشغ

    THANKS FOR GIVE ME YOUR TIMES
    SINCERELY
  • 0 in reply to reza jadidi
    Prodigy 250 points
    THANKS JOSE.
    ABOUT ABOVE YOUR STATEMENT,YES I POWERD ADS8329 AND MICRO IN SAME TIME.IN SOFTWARE CONVST PIN IS UP AND FOR START CONVESION GO DOWN CONVST PIN FOR 100NS,AND UP.I EXPECTION IMMEDIATELY EOC GO DOWN AND AFTER ABOUT 18 CCLK EOC GO UP.

    MY SOURCE QUESTION AND DIFFICULT WAS THIS =WHEN POWERD ADS8329 PIN9=EOC STAY LOW(I EXPECTION GO UP)BUT SOME TIMES GO UP BUT NOT TRUE WORKS!!??
    I HAVE SOME QUESTIONS.(PLEASE GIVE ANSWER IN SIMPLE ENGLISH)
    IN DATASHEET CCLK MIN=21 AND MAX=24.5
    HOW CAN I KNOWN CCLK FREQUENCY FOR PRECISION TIMING?
    I WANT GET 20 SAMPLE IN 20US!

    IF IN+ SIGNAL GO UP 8V FOR 1US ADS8329 CORRUPT?
    I NEED Consultation FOR CONDITIONING FOR IN+ INPUT IN NEXT DAY

    THANKS FOR GIVE ME YOUR TIMES
    SINCERELY
  • 0 in reply to reza jadidi
    Prodigy 250 points
    Hi.
    IN PAGE 26 WRITE
    (The EOC output goes low for 3 conversion clocks (CCLK) after the previous rising edge of EOC, if auto
    trigger is programmed)

    I SEE FIG2 AND FIG4. FOR 3CCLK GO UP.

    QUIZ: IN ADS7816 AND SOME ADC CONVERTER YOU CAN GET SAMPLE IN PRECISE TIME WHEN GO LOW CS PIN.
    AND GET ADC OUTPUT IN SOME CLOCK AFTER SAMPLING WRITE IN DATASHEET.

    BUT IN ADS8329 HOW CAN GET PRECISE TIME SAMPLE FROM MY SIGNAL.WHEN I GO LOW CONVST PIN ADS8329 CONVERT LAST SAMPLE OF SIGNAL!!

    SINCERELY
  • 0 in reply to reza jadidi
    TI__Genius 9975 points

    Hello Reza,

    The best way to ensure exact CCLK timing is to program the ADS8329 to run based on the external serial clock, SCLK. Please remember that the serial clock SCLK, is first reduced to 1/2 of its frequency before it is used as the conversion clock (CCLK).

    You can find more information on how to design the input circuitry for SAR ADCs in the following TIPD: http://www.ti.com/tool/TIPD151

    If your CONVST pulse has at least 20 ns of setup with respect to the rising edge of SCLK (assuming you programmed the ADS8329 to run based on the external serial clock, SCLK) then you can count on having a result in 42 SCLK cycles.

    Hope this helps.

    Best regards,

    Jose

     

  • 0 in reply to Jose Duenas
    Prodigy 250 points
    Hi.
    thanks.
    i have questions?
    ads8329 EOC CONNECT TO Microcontroller PIN.
    I DO MICRO PIN INPUT PIN STATE BUT EOC INPUT PIN WILL BE PULL UP OR PULL DOWN?
    PUSHPULL OR OPENDERAIN?

    MISO PIN WILL BE PULL UP OR PULL DOWN?

    THANKS