PAA5100JE - Troubleshoot failure to registerRead call

I have 2 PAA5100JE that have been monitoring successfully, the flow rate of coffee beans in my Arduino based, DIY coffee roaster.

A couple weeks ago both failed to initiate, but still partially work. Because these are not cheep (~$25 each – $50 total) I am looking a bit deeper before I throw them away and buy two more.

I have searched the internet and found some information, but nothing about partial failures. I found there is a document with in depth information about this product, not in the public data sheet, but I would have to get it from the manufacture. Perhaps you have it?

My troubleshooting shows the failure is partial. SPI works, and registerWrite functions work. For example I can write to the LED register, to turn the LEDs on and off just fine.

But any calls to registerRead, for any registry, return the same value 255. Even calls to the register for the LED light returns the value 255 - regardless if it is on or off.

How does this registerRead work? Can I use a reset function?

The failures did occur after two power outages - but its does not make sense that a power surge would remove just one function.

Thanks!

Are the two sensors clean and free of dust etc?

Yes they’re very clean.

What I want to see is how they implemented the SPI read protocol.

I’m hoping the devices are not burned out but rather the SPI registers need to be reset. I would need to see the vendor documentation to see if there is a reset option.

I read in a comment to another post in this forum, that the vendor does have some advanced documentation on the SPI protocol they mplemented.

I’m wondering if you have this documentation or can you get it from the manufacturer.

I tried to, but they only want to deal with vendors and companies, not individuals

Here is some new information.

The voltage of devices MISO pin is continuously high - at 3.7. This would explain why all registry read are at 255.