ADS1298 don't express any coherent signal

Luigi Nery

Other Parts Discussed in Thread: ADS1298

Hi,

I'm using ADS1298 in a project and I tried to test it, but the converter do not send a coherent signal. The only I have are random spikes (maybe white noise) on output. I checked SPI and it works fine. This is my configuration vector:

const byte adsConfigRegs[] = {
    0x06, // Config 1 - low power, daisy-chain, 1kS
    0x13, // Config 2
    0xc0, // Config 3
    0x00, // LOFF

    0x15, // CH1SET 11
    0x15, // CH2SET 10
    0x15, // CH3SET 10
    0x15, // CH4SET 11
    0x15, // CH5SET 11
    0x15, // CH6SET 11
    0x15, // CH7SET 11
    0x15, // CH8SET 11

    0x06, // RLD_SENSP
    0x02, // RLD_SENSN

    0x00, // LOFF_SENSP
    0x00, // LOFF_SENSN
    0x00, // LOFF_FLIP

    0x00, // LOFF_STATP
    0x00, // LOFF_STATN

    0x0f, // GPIO
    0x00, // PACE
    0x00, // RESP
    0x00, // Config 4
    0x00, // WCT1
    0x00 // WCT2
};

With this configuration, I put it in RDATAC mode and the triggered interrupt generated by DRDY pin is handled and all output data is read. When I change the switch among the different input signals I can notice some change on output signal behavior, but still a messy signal.

I can send you more datails from my configuration and code.

over 9 years ago

0 Brian Pisani over 9 years ago

TI__Mastermind 38745 points

Hey Luigi,

Your configuration indicates you are converting the internally generated DC test signal. I expect the output to look like a voltage centered at -1mV. Is that the case? Try changing the test signal to one of the ac signals by changing CONFIG2[1:0] to wither 00 or 01. If you have tried that and it does not work. Send me raw data to look at.

Regards,
Brian Pisani

0 Luigi Nery over 9 years ago in reply to Brian Pisani

Prodigy 115 points

Brian,

Now im reading CH2 with your suggested value (CONFIG2[1:0] = 0) and applying sprintf() to the data.

See in the link what I received:

http://pastebin.com/A90iYGe1

Thanks,

0 Brian Pisani over 9 years ago in reply to Luigi Nery

TI__Mastermind 38745 points

Hey Luigi,

I can't access file sharing websites from TI's network. Would you mind attaching it to an e2e post by clicking "Use rich formatting" then clicking the paperclip symbol to browse your directory for the file?

Thanks,
Brian Pisani

Data converters

Data converters forum

ADS1298 don't express any coherent signal