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ADS1299: ADS1299 output error data.

Sangkyu Kim
Intellectual 290 points
Part Number: ADS1299

Hi,

I test my ads1299 evm using stm32MCU.

Next channel of Power on chennel, the unknown hex data(0x10000) output.

For example, Internal test signal output on 1,3,5, and power down 2,4 channel,

output the below waveform.

This is my register setting.

/****************************setup register******************************/
Device_ID=ADS1299_Read(REG_ID);
ADS1299_Write(REG_CONFIG1, 0x95); // default value= 0x96, about Data rate setting
ADS1299_Write(REG_CONFIG2, 0xC0);
ADS1299_Write(REG_CONFIG3, 0xFC); // default value= 0xE0, DRL ON= 0xFC
Spi1WriteByte(RDATAC);

/***********************************************************************/


/****** SQUARE WAVE TEST SIGNAL ******/
Spi1WriteByte(SDATAC);
ADS1299_Write (REG_CONFIG3, 0xE0);
ADS1299_Write (REG_CONFIG2, 0xD0);
ADS1299_Write (REG_CH1SET, 0x65);
ADS1299_Write (REG_CH2SET, 0xE5);
ADS1299_Write (REG_CH3SET, 0x65);
ADS1299_Write (REG_CH4SET, 0xE5);
ADS1299_Write (REG_CH5SET, 0x65);
ADS1299_Write (REG_CH6SET, 0xE5);
ADS1299_Write (REG_CH7SET, 0xE5);
ADS1299_Write (REG_CH8SET, 0xE5);
Spi1WriteByte(RDATAC);
/*************************************/



/************ LOFF Setting ************/
Spi1WriteByte(SDATAC);
ADS1299_Write (REG_LOFF, 0x00); // Lead_off setting (comp_level,current amplitude,DC/AC)
ADS1299_Write(REG_CONFIG4, 0x02); // Lead_off comparator power ON=0x02, OFF=0x00
ADS1299_Write (REG_LOFF_SENSP, 0xFF);
ADS1299_Write (REG_LOFF_SENSN, 0xFF);
ADS1299_Write (REG_LOFF_FLIP, 0x01); // Lead_off curent direction
Spi1WriteByte(RDATAC);
/*************************************/


/************ RLD Setting ************/
ADS1299_Write (REG_RLD_SENSP, 0x06); //CH1P RLD
ADS1299_Write (REG_RLD_SENSN, 0x02); //CH1N RLD
/**************************************/

Off the 1,2,4 channel, output the below waveform.

This is my register setting.

/****************************setup register******************************/
Device_ID=ADS1299_Read(REG_ID);
ADS1299_Write(REG_CONFIG1, 0x95); // default value= 0x96, about Data rate setting
ADS1299_Write(REG_CONFIG2, 0xC0);
ADS1299_Write(REG_CONFIG3, 0xFC); // default value= 0xE0, DRL ON= 0xFC
Spi1WriteByte(RDATAC);

/***********************************************************************/


/****** SQUARE WAVE TEST SIGNAL ******/
Spi1WriteByte(SDATAC);
ADS1299_Write (REG_CONFIG3, 0xE0);
ADS1299_Write (REG_CONFIG2, 0xD0);
ADS1299_Write (REG_CH1SET, 0xE5);
ADS1299_Write (REG_CH2SET, 0xE5);
ADS1299_Write (REG_CH3SET, 0x65);
ADS1299_Write (REG_CH4SET, 0xE5);
ADS1299_Write (REG_CH5SET, 0x65);
ADS1299_Write (REG_CH6SET, 0xE5);
ADS1299_Write (REG_CH7SET, 0xE5);
ADS1299_Write (REG_CH8SET, 0xE5);
Spi1WriteByte(RDATAC);
/*************************************/



/************ LOFF Setting ************/
Spi1WriteByte(SDATAC);
ADS1299_Write (REG_LOFF, 0x00); // Lead_off setting (comp_level,current amplitude,DC/AC)
ADS1299_Write(REG_CONFIG4, 0x02); // Lead_off comparator power ON=0x02, OFF=0x00
ADS1299_Write (REG_LOFF_SENSP, 0xFF);
ADS1299_Write (REG_LOFF_SENSN, 0xFF);
ADS1299_Write (REG_LOFF_FLIP, 0x01); // Lead_off curent direction
Spi1WriteByte(RDATAC);
/*************************************/


/************ RLD Setting ************/
ADS1299_Write (REG_RLD_SENSP, 0x06); //CH1P RLD
ADS1299_Write (REG_RLD_SENSN, 0x02); //CH1N RLD
/**************************************/

Not only internal test signal but also input EEG signal.

Additionally, my square test signal show overshoot....

Is there any problem?

I attach my raw data file, Fs=500Hz.

square wave.txt

  • 0
    TI__Guru 66466 points

    Hello Sangkyu,

    When you power down a channel, it is recommended to short the channel inputs together. This may help to eliminate the unwanted noise for those channels. You can short the inputs by writing 0xE1.

    Sangkyu Kim said:
    Next channel of Power on chennel, the unknown hex data(0x10000) output.

    I did not understand what you meant by "unknown hex data," could you please elaborate?

    Sangkyu Kim said:
    Not only internal test signal but also input EEG signal.

    I think what you meant to say here is that the channels with 0xE5 show unwanted noise, both for internal test signal configuration and for external applied EEG signal. Is that correct? Again, my recommendation is to short the inputs together for all powered-down channels. This should help with the unwanted noise coupling.

    Thanks and regards,