ADS7953: ADS7953 get bad datas in AUTO-1 mode

Hello user3681320

This could be issue related to timing mismatch between SPI signals. Can you capture SDI/CS/SCLK/SDO signals on scope and share the details.

One more way to validate if it is a timing related issue is to set device is manual mode and repeatedly monitor only one channel (preferrably channel on which you are getting incorrect data). Data you get back from ADC should be same in each case. If it is not then it is timing related issue

Thanks & Regards

Abhijeet

Hello, Abhijeet Godbole!

I have resolved the problem because of the power on my board.

But now I have a new problem, I receive data from ADS7953 like this:

xxxx ( first I get this one after ADS7953 initialization )
0xxx
1xxx
2xxx
3xxx
4xxx
5xxx
6xxx
7xxx
8xxx
9xxx
Axxx
Bxxx
Cxxx
Dxxx
Exxx
Fxxx

0xxx
1xxx
2xxx
3xxx
4xxx
5xxx
6xxx
7xxx
8xxx
9xxx
Axxx
Bxxx
Cxxx
Dxxx
Exxx
Fxxx

...

My Code is:

// Request next frame to enter programming mode for Auto Mode 1
spi1_send_data(ADS79XX_PROG_AUTO1);

 
// Program Auto Mode 1 Channel Sequence to include all channels
spi1_send_data(AUTO1_ALL_CHAN_ENABLE);

 
// Program Auto Mode 1 Range and configuration settings
spi1_send_data(ADS79XX_AUTO_MODE1 | AUTO1_PROG_ENABLE | AUTO1_CHAN_COUNT_RESET | AUTO1_5VRANGE_SEL | AUTO1_NORM_OP_SEL | AUTO1_CHAN_ADDY_SEL);

 
while(1)
{
    res = spi1_send_data(0x0000);      // first I get xxxx ( only  once )
    printf("%x\n",res);  
    delay_ms(2000);                    
}

Why do I get the xxxx  in the beginning?  Please help me, thanks!

Hello

First conversion after power up or reset is invalid and should be ignored. Please refer to electrical char table specs on page12 fo datasheet for more information

Thanks

Abhijeet