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ADS1299: ADS1299 Daisy Chain

Sumit Mourya
Expert 1790 points
Part Number: ADS1299

Hello All,

I'am designing a 24 channel EEG System and planning to use 3 ADS1299 in Daisy Chain Mode. I have few doubts regarding sharing common signals between the 3 Chips.

Can I Share the RESET Pin of all 3 IC's together with One GPIO of the MCU or should I dedicate Separate GPIO Pins of the MCU to each ADS1299 RESET Pin?
Can I Share the START Pin of all 3 IC's together with One GPIO of the MCU or should I dedicate Separate GPIO Pins of the MCU to each ADS1299 START Pin?
The CS Pin of all 3 ADC's are connected together. This should further be connected to GPIO of the MCU Or The SPI CS Pin of the Microcontroller?

Also In Daisy Chain Mode I have to send the ADC Registers settings only once for all the 3 ADC's?

  • 0
    TI__Guru 66346 points

    Hello Sumit,

    Thank you for your post!

    /RESET, START, and /CS pins on multiple ADS1299 devices can be tied together and shared with the same pin on the MCU. The /CS pin can be tied to GPIO on the uC or to the dedicated /CS pin of the SPI peripheral. That's up to you, but as long as all timing requirements are satisfied, it makes no difference to our ADS1299.

    In daisy-chain configurations, the /CS and DIN pins will all be tied together and shared with one MOSI pin on the uC. You will only be able to write the same register settings to all ADS1299 devices in this setup. If you require different register settings for each device, you will need to use multiple GPIOs to act as separate /CS signals. DIN can remain shared with all ADS1299 devices. This will allow you to write register settings to one ADS1299 device at a time. When reading data, all /CS signals can be brought low at the same time and data will be clocked out in daisy-chain fashion through the first ADS1299 DOUT pin.


    Best regards,