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HDC2080: Value return of 0x0 on 1.5ms Delay

Part Number: HDC2080

we were recommended to add a 1.3 ms delay to allow the HDC2080 to take a measurement. We are now testing larger number of samples and have a 1.5 ms delay in place.

 

However, on a small number of units, we are again getting the same values of 0,0 returned for both temperature and humidity. It is intermittent, but on some units we are seeing up to 10 % of measurements with this issue. All testing at the moment is at room temperature. We are still to do larger temperature ranges.

 

Any ideas on the solution? Do we just continue to increase the delay?

  • Calum - 

    The best way to troubleshoot this (if it is possible on your side) with you would be for you to put logic analyzer on the I2C lines and let us see what is being sent and returned, as well as the timings. I personally have not seen much variation in the conversion time, and the DRDY/INT line as well as the register 0x04 (MSbit) can be used to indicate when valid data is ready from the part. I very much recommend using the DRDY/INT line in conjunction with that register for best performance of the overall system. Look forward to seeing these details and helping you. 

  • Calum - 

    Thanks for sending the logic analyzer capture over email - that was most appreciated. 

    As stated in my reply to my email, in looking at that capture, I would recommend they wait >1.3mSec, then send the pointer and read the parts – in the capture you sent over, they start conversion, immediately set the pointer to 0x00, then wait 1.7mSec, then read.

    Obviously it works most of the time, but it seems odd to me.

    I have not ever seen the approach (below and attached) fail and reading the 0x04 register also is equally effective – here (in the attached Saleae logic analyzer capture) I am doing both for redundancy.

    HDC2_timing_DRDY_INT_0x04_usage.logicdata