ADAS1000 pace data readout

Hi All,

One of my customers is making evaluation test by using EVAL-ADAS1000SDZ and EVAL-SDP-CB1Z.

The evaluation boards works well at her desk now.

In addition to this evaluation kit, she wants to read out the pace data separately from this evaluation kit.

She wants to connect SPI bus from her MCU board to EVAL-ADAS1000SDZ J4 connector and read out the pace data from ADAS1000 pace register.

I think that it seems difficult because two controllers (Controller in SDP board and her MCU board) connected to one ADAS1000 and works independently. Data readout collision may occur.

Do you have any advice to export the pace register data to externally located MCU?

Best Regards,

Ricky

  • 0
    •  Analog Employees 
    on Jun 4, 2015 10:33 AM

    Hello Ricky,

    Thank you for your email.

    When you say "Pace data", I believe you are referring to the Secondary SPI interface which provides 128kHz ECG data results. For background, this interface is provided for users that might want access to the high data rate ECG results and process them independently to the ECG results available on the standard SPI interface.

    One reason they might wish to do this is where they have their own digital pace algorithm and wish to have the high speed ECG results to run their algorithm on the data.

    This "Secondary SPI" interface is a Master interface as far as the ADAS1000 is concerned - so the ADAS1000 is generating the SCLK, CS, SDO signals. In this case the Micro needs to be configured as the slave - just reading data back from the ADAS1000.

    This Secondary SPI interface is independent from the primary SPI interface which is used for register control and conversion results readback at 2kHz, 16kHz, 128kHz data rates).

    In the configuration that you have described, your customer is using the ADI ADAS1000 evaluation board and the SDP controller board to interface to the standard SPI interface. She then wishes to connect to the Secondary SPI interface via the J4 header connector on the board. Because the ADAS1000 secondary SPI interface is a master interface and independent to the primary SPI interface, I think that it should be ok to connect the other micro to the J4 connector without concern for data readout collision....The other micro will of course need to be connected into the same ground as the adas1000 evaluation board, it should also be operating at the same IOVDD levels (interface supply voltage).

    If your customer is having issues, can you get a detailed description with configuration drawing of how the system is connected etc.

    I hope this helps, please let us know if you have further questions.

    Best regards,

    Catherine.

  • Hello CatherineR-san,

     

    Thank you very much for your reply.

    Yes, I am referring to the Secondary SPI interface.

    Let me clarify the 128kHz ECG data, is it just a series of A/D converted ECG signal data, and not the pace detected data?

    User must need to get pace data by using the ECG data and her own pace detection algorithm on outside processor.

    Also, user can't access the pace detected data in register of ADAS1000 via the Secondary SPI interface.

    Is this my understanding correct?

     

    Best Regards,

    Ricky.

  • 0
    •  Analog Employees 
    on Jun 8, 2015 7:05 AM

    Hello Ricky,

    That is correct. The secondary SPI interface provides ECG converted data.

    The user can then take this data and implement their own digital pacemaker detection.

    hat are you trying to achieve? Or expecting? If you can explain, perhaps I can help.

    Alternatively, the user can use the regular SPI interface and the internal ADAS1000 pace detection algorithm. This pace detection algorithm assesses the incoming ECG signal and if it finds what it deems to be a valid pace artifact, this will be identified by a pace detection flag and there are also options to read back the measured pace height and width.

    There is an extensive discussion of the pace detection on page 42 of the datasheet.

    Please let us know if you have further questions.

    Best regards,

    Catherine.

  • Hello CatherineR-san,

     

    Thank you very much for the clarification.

    My customer is expecting to read out the pace data registers inside of ADAS1000 by externally connected MCU via 2ndary SPI bus while the user interface of the evaluation board is working on her PC. This expectation rests on the premise that the pace data register can be accessed via 2ndary SPI bus as well as primary SPI bus.

    Now I understood that the 2ndary SPI bus is master SPI bus and will not be able to read out the pace data register via 2ndary SPI bus.

    Is my understanding collect?

    If my understanding above is correct, my advice to her will be that she should detect the pace data by using ECG data via 2ndary SPI bus and referring to the algorithm of figure 74 in data sheet which will run on externally connected MCU.

    Thank you for your help.

    Best Regards,

      Ricky

  • 0
    •  Analog Employees 
    on Jun 9, 2015 9:25 AM

    Hello Ricky,

    Thanks for response.

    Yes, your understanding is correct. The Secondary SPI is a master SPI bus and provides converted ECG results.

    Your customer can use the ADAS1000 Pace algorithm inside of the chip.

    As explained earlier, this algorithm analyses the converted ECG data and searches for a pace signal, if it finds it, there will be a flag that a pace was detected.

    User has control over certain parameters of the ADAS1000 pace algorithm - e.g. See the Pace configuration registers PACECTL,  PACEAMPTH, PACEEDTH, PACELVLTH. (these are accessible through the standard SPI interface). The Pace detected flag and optional width/height of pace are also available through the standard SPI interface.

    best regards,

    Catherine.