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No data out of the ADS1282

Sergio Cruz Perez
Prodigy 50 points
Other Parts Discussed in Thread: ADS1282, ADS131E04

Hi,

I'm trying to communicate a stellaris launchpad to an ads1282 but i don't get data from the converter.

CLK=4.096MHz    OK

Vref positive=2.5V OK

Vref negative=-2.5V OK

AVDD=2.5V OK

AVSS=-2.5V OK

I have a electrolitic capacitor connected to the bypass line

PWD and RESET to 3.3V

Input signal=sin wave 1Vpp @ 1Hz

 a 10nF ceramic capacitor connected to Capn y Capp, each line with a 75kohms to -2.5V and 2.5V (geophone application in the datasheet)

 

Fig. 1 DRDY (yellow signal) and DOUT (blue signal)

 

Fig. 1 SCLK (yellow signal) and DIN(blue signal)

Could the SPI interface of the converter be damaged?  

 


 

 

 

  • 0
    Intellectual 335 points

    If you try to read anything and it doesn't work try to send SDATAC command firts and then read/write other things. I had long battle with ADS131E04 (either a SPI device) and that was the reason. Very poorly described on right-top of page 34 of your ADC datasheet.

  • 0 in reply to Ireneusz Magiera
    Prodigy 50 points

    Hi Ireneusz,

    Thank you for your answer. It was very helpful. I read data by command instead of continuous and i get data from the converter. So, the SPI interface is working correctly.

    After that, I checked the configuration of the SSI module and I saw that the frame format it was the motorola mode 2 (polarity=1 phase=0):

    SSIConfigSetExpClk(SSI0_BASE, SysCtlClockGet(), SSI_FRF_MOTO_MODE_2, SSI_MODE_MASTER, 1000000, 8);

    I changed the format to Motorola mode 0 (polarity=0 and phase=0) and the problem was solved

    SSIConfigSetExpClk(SSI0_BASE, SysCtlClockGet(), SSI_FRF_MOTO_MODE_0, SSI_MODE_MASTER, 1000000, 8);

     

    Thanks

    Regards

     

    Sergio