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ADS1263: SPI Communication with ADS1263 and ATxmega256a3bu

Part Number: ADS1263

Hello,

i'm using the ADS1263 with the atxmega256a3bu microcontroller. I got now problems to configure the SPI communication.

(I've added the schematics in the attachments.)

The problem is, that i cant get any signal at the MISO(DOUT/DRDY) line. 

Im using Spi_mode1, 500kHz and i'm reading directly from the ADC like describted in the datasheet of the ADS1263 on page 68.

Now the problem is, that my DRDY pin (which to synchronisize with) never gets low, even if i toggle the reset-pin for 1s (sleep mode <9ms or so), the DRDY Pin stays always high.

Is it an indication for that the ADS1263 is broken or are there any mistakes in the schematics?

In my C-Code, i pull the CS and MOSI(DIN) line permanently low, and the start pin always high. Than i wait with:

while(!(PORTA.IN & 0x10));

for getting DRDY low (PortA - pin4), to read 6 Bytes (1 Status 4 Data 1 CRC Byte) afterwards and putting them in an array.

But like already mentioned, DRDY never goes low, and the microcontroller stucks in the while loop.

What can i do?

I will be thankful for every reply on this post.

Mikrokontroller_ATXmega256A3BU_Schaltplan.pdfADS1263 + MCxmega.rar

1 Reply

  • Hi Ratimir,

    Welcome to the TI E2E forums!

    Before debugging the SPI communication I would focus on the /DRDY issue. When the ADC is converting, you should see /DRDY pulsing at regular intervals (1/data rate, to be exact). If /DRDY is not pulsing it could be an indication of one of the following problems:

    1. The ADC is not properly powered.

    Looking at your schematic, I didn't see an obvious place to connect the power supply(ies) ground to the GND of the ADC board, particularly if you're using a bipolar supply. If however, you're using the unipolar supply mode (AVDD = 5V and AVSS = 0V), you could connect all of your supply grounds to AVSS...I would double check that your supplies are properly connected and the ADC is powered.

     

    2. The ADC does not have a clock signal.

    You're using the internal oscillator (XTAL1 connected to GND), so this shouldn't be an issue.

     

    3. The ADC is in power-down mode or is not converting.

    Check the logic levels of the PWDN and START pins. Both pins should be high to activate the device.

     

    4. The ADC may be damaged if all of the above conditions are meet, but still no /DRDY signal is seen.

    I would suggest probing the /DRDY signal with an oscilloscope to check if it is toggling, just in case the microcontroller is not registering the /DRDY low condition.

     

    Another note, if you're jumper wiring the MCU board to the ADC board, make sure to keep the jumper wires short and close together to avoid excessive inductance on the SPI signals. Also, don't forget to connect the PCB grounds together (...I have forgotten to make this connection!).
     

    Best Regards,
    Chris


    Christopher Hall | Δ-Σ Data Converter Applications
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