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Original question:

LDC1101: RCOUNT, resolution and sample rate

LDC1101: multiple LDC1101 synchronization

Michael9q
Intellectual 565 points
Part Number: LDC1101

Hello there,

I would like to ask for recommendation how to synchronize multiple LDC1101s?

I need to have two or more LDCs running at same conversion interval and based on MCU's decision it is chosen which sensor will be used. No matter which sensor is chosen both must have same response time.

I can see that LDCs would share same oscillator and they would be waken up for conversion mode at same time. They should have data ready at same time as well. But then they got misaligned due to different data read out from data registers. Next conversion interval one sensor is ready earlier since it was read out in previous conversion interval as first and as first it started new conversion interval. Correct?

Please let me know about possible approach.

Thank you very much,

Michael 

  • 0
    TI__Mastermind 18545 points

    Hello Michael, 

    The LDC1101 conversions should operate at the same speed once they are setup and started at the same time. The conversion interval is independent on the SPI communication but the data that you read might not be sequential if you aren't able to read registers faster than the conversion time. The issue with getting the conversions synchronized, is waking up the different devices from sleep. If you can be very precise with your wake up command (or if you can have some tolerance in your synchronization), you could wake up a device to line up the conversion time of an already started one. The timing requirements and SPI programming sections of the datasheet can be used to calculate this time for your application. 

    Hope this helps,