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Original question:

ADS8681: Daisy chain in ads8681

ADS8681: Daisy chain in ads8681

Kanchan
Expert 1445 points
Part Number: ADS8681

Dale Li wrote the following post at Feb 12, 2019 5:54 PM:Hi Kanchan,
I assume that you are using below connections to your microcontroller(as a master):
1. Using SDI from CN3 connector to your microcontroller's MOSI.
2. Using SDO from CN5 connector to your microcontroller's MISO.
3. You are not using SDO from CN3 and SDI from CN5.
If my understanding is correct, these connections are right, but you will have to program the configuration register in each ADC device with identical values The device must operate with single SDO-0 output. Also, bits 7-0 in SDO_CTL_REG register must be programmed to 00h.

Thanks.
Regards,
Dale

yes absolutely! the connection are right..i could configure only one of the device couldnt make same the same configurartions for second device..i dont understand where am i mistaking.

see as per datasheet the configuration should be done with 32 bit reg and clock so if i need to make it for 2 devices i just need to repeat the same instruction of configuring registers for the two time? right?

i have done the same procedure..but i could read the output of the second device only not the first device..that i identified from the inputs provided. .

tell me what is the role of reset bar...i have tied both the reset bar to VCC.

  • 0
    TI__Mastermind 45915 points

    Hi Kanchan,
    You will have to program DEVICE_ID_REG register(bits [19-16]) with a unique identification number associated to a device that is used in the daisy-chain configuration, please follow the daisy-chain mode timing in Figure 73 of datasheet, these three configuration data should not be same because different device ID. For normal conversion after configure these two ADC devices properly, three same configuration data(32-bit) can be used to read the conversion data from ADCs, for example, NOP command with all zero data to ADC.
    Please let me know if you have done this, thanks.

    Regards
    Dale