This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

ADC1256 not responding

< I am using 8 ADS1256 adc's in a board and through FPGA reading the output to microcontroller on multiplexing basis

but whatever command I give ADC gives output as 00 even no data is coming on DOUT pin.

even I am not able to read configuration registers
> <please give some hints to solve this problem>

Parents
  • "in datasheet it is not given while reading or writing to status registers we have to give reset command or not."

    If the datasheet doesn't mention it, why would you assume that it would be necessary?

    This is what the datasheet says about RESET:

    "On reset, the configuration registers are initialized to their default state..."

    So what would be the point in writing to a register and then resetting the chip?

Reply
  • "in datasheet it is not given while reading or writing to status registers we have to give reset command or not."

    If the datasheet doesn't mention it, why would you assume that it would be necessary?

    This is what the datasheet says about RESET:

    "On reset, the configuration registers are initialized to their default state..."

    So what would be the point in writing to a register and then resetting the chip?

Children
  • Wrong values are read from the chip because we are seeing the output signal coming from ADC output pin on the oscilloscope.
    Input to the ADC is given correctly which we have seen on the oscilloscope with
    120ns setup time
    and 127ns hold time.

    one more thing we have noticed is that on power up even when CLKIN is high and no other pin is having any other clock but still the D0/CLKOUT pin shows a clock of 16MHz clock, which is same as the system clock present for the microcontroller.

    DRDY period doesn't changes according to the data rate,
    sometimes it changes and sometimes it doesn't.
    for example when we made data rate as 30Ksps and 15 ksps the DRDY period was same that was 60us.
    and when we changed it to 1 KSPS DRDY period changed.
    Clock input I am giving as 4.2 MHz.

    Can it be possible because of not providing proper ESD protection the chip got damaged?

  • The analog side of a 24bit ADC is far more likely to be damaged by ESD than the backend computer interface.

    If D0/CLKOUT/DRDY are signals that are expected to be driven by the ADC, have you made sure that it is infact the ADC that are driving them, so the FPGA doesn't do something weird?

    Without looking in your data sheet: Is DRDY a signal that should change based on the baudrate, or is it a signal that should change whenever a new sample has been converted and is possible to read? If the second, then the DRDY frequency should normally not be affected by the baudrate.

  • d0 clkout is not connected to FPGA so no chance of driving that pin by FPGA
    And regarding drdy, signal on power up it shows a periodic signal of particular period depending on the data rate .
    Why it is like that I don't know

  • Initially on power up itself, DRDY pulse starts coming please anybody tell me what may be the possible reason of this.
    I am getting a continous pulse on drdy.

  • It means that the ADC is continuously making conversions, and the signal informs when a conversion is ongoing, and when data is available. Every time the signal goes low, it informs that a new conversion is started.

    This information is available in the datasheet.

  • hi all
    i have to interface the ADS1256 with msc1210 microcontroller but i have no idee for the way to use it! could you help me
    thanks

  • The links to the datasheet & manufacturer's product page have already been given - that would be the place to start!

    Also, I think the msc1210 is an 8051-derivative - not 80251?

  • yes it is the same !!have you got some example?