I am using this ADS1299 Frontend Board with a Rp2040 Pico, my SPI connections and lib work fine, but I am facing problems in understanding how to use a refference electrode, I am getting good signals but I want to remove/reduce the powerline noise from my sEMG's.
I am getting signals form 8 channels, and need only one more electrode as a refference electrode, which will be connected to the user's arm to reduce poweline/AC noise, where to connect it, and is there any other component or circuit between the ADS1299 chip and the reffernce electrode which I should implement in my custom circuit which I am trying to build nothing else.
Here is my initial settings for the registers:
ADS.verbose = true; // Enable verbose mode for serial feedback
ADS.RESET(); // Send RESET command to default all registers
ADS.SDATAC(); // Exit Read Data Continuous mode to communicate with ADS
ADS.WREG(CONFIG1,0b00000101); // Write to CONFIG1 register, set data rate to 256 SPS
ADS.WREG(CONFIG2,0b11010101); // Write to CONFIG2 register
ADS.WREG(CONFIG3,0b11001100); // Write to CONFIG3 register, enable bias measurement and internal reference buffer
// Write to CHxSET registers, enable all channels and connect them to normal electrode input
ADS.WREG(CH1SET,0b00000000); // Enable channel 1
ADS.WREG(CH2SET,0b00000000); // Enable channel 2
ADS.WREG(CH3SET,0b00000000); // Enable channel 3
ADS.WREG(CH4SET,0b00000000); // Enable channel 4
ADS.WREG(CH5SET,0b00000000); // Enable channel 5
ADS.WREG(CH6SET,0b00000000); // Enable channel 6
ADS.WREG(CH7SET,0b00000000); // Enable channel 7
ADS.WREG(CH8SET,0b00000000); // Enable channel 8
// Write to BIAS_SENSP and BIAS_SENSN registers, select all channels for bias drive signal
ADS.WREG(BIAS_SENSP,0b11111111);
ADS.WREG(BIAS_SENSN,0b11111111);
// Write to LOFF_SENSP and LOFF_SENSN registers, enable lead-off detection on all channels
ADS.WREG(LOFF_SENSP,0b11111111);
ADS.WREG(LOFF_SENSN,0b11111111);
ADS.WREG(CONFIG4,0x02); // Write to CONFIG4 register
ADS.RREGS(0x00,0x17); // Read all registers starting at ID and ending at CONFIG4
ADS.RDATAC(); // Enter Read Data Continuous mode
ADS.START(); // Start the ADS1299 device
