HDC2010: Erroneous values for temperature and RH, when RH < 3%

Hi Alex,

Thank you for the fast response. The firmware waits 2ms, so this isn't the case, unless the MCU crystal operation fails for some reason. However, I'll made improvements in that direction, thank you!

Can you guide us to the route cause of the problem on the attached file? Now the values for temperature and RH aren't 0. The RH is 99.6% and the temperature suddenly jumps with around 3 Celsius degrees. Any help is highly appreciated!

That problem looks like that one: https://e2e.ti.com/support/sensors-group/sensors/f/sensors-forum/1017648/hdc2010-erroneous-temperature-data-and-hh_status-1/3761854?tisearch=e2e-sitesearch&keymatch=hdc2010%25200xfe#3761854

I use 8 bit data representation for the humidity, so 99.6% RH in raw is 0xFFFE.

Our device is battery powered, so increasing the current consumption is not an option.

I hope now good solution will be possible.

Best regards,

Martin Peevski

Alex,

Unfortunately we can't read the registers in this moment on the client devices.

Before we was facing bad temperature values and HDC2010 software reset seems to fix that problem.

Do you think just software reset will fix and that problem?

I can make HDC2010 to be reseted when the read RH is above, let's say, 80%. What do you think?

Martin,

If that has worked for you in the past, then I would suggest you implement that. Especially if you cant implement the higher current demanding software fix I sent you. On previous E2E threads about this I have also seen 2 software resets can help, so you can try that as well.

I do suggest that you try the software fix I linked on at least 1 HDC2010 setup, just to see if that will resolve the issue. What supply voltage are you operating at?

Thanks

-Alex Thompson

Alex,

We work on 3V.

Martin,

Would it be possible for the customer to step that down to below 2.2V? The floating node issue will only appear above 2.2V.

Thanks

-Alex Thompson

No, it isn't possible.

I'll try reseting (once) the HDC2010 at invalid humidity, too.

Alex,

Since the document says that the device sleep mode current will be 200uA, using the software workaround, that doesn't work for us. We are battery powered.

Can you say, when we detect invalid humidity value, will be the temperature value also invalid?

Best regards,

Martin Peevski

Alex,

The floating node software fix sequence can't be tried out, the devices are at clients.

Just software resets still not tried out, but that's the only solution we can make.

HI Martin,

Thanks, that makes sense. I may have asked this already, but how many HDC2010s are showing these bad reads? All of the ones your customer has, or only some?

Thanks

-Alex Thompson

Hi Alex,

Not all of the devices the customer have are with the problem.

What that talks to you?

Martin,

It just lends more credit to the floating node bug being the issue. If the customer has a mix of older and newer HDC2010s, that's how this can show up on only some devices. If there was a problem with the communication or PCB on the customer's end, they shouldn't see only some of the parts having this issue.

Could you please elaborate why the other HDC2010 registers cant be read on the client devices? Having the register dump info when a mis-read occurs would be helpful.

Thanks

-Alex Thompson

These are radio devices which our client sale to his clients. Investigating further the problem requires efforts from our client, too.

Martin,

I understand, but we are going to need the customer to try either the floating node software fix or at least provide a register dump to get started on this debug (if they opt for only a register dump, we need the register information when a bad RH read occurs). I cant proceed without this information. We need to see if they are dealing with the floating node issue.

Thanks

-Alex Thompson