About bartb_firmwave

Thank you for your response and help, much appreciated. I agree that's probably all we could do here, especially the interface I could use is not responding . I will try to contact the supplier to make physical analysis as it's very important to us to determine what might have been the cause and learn how to avoid those situations. Once again, thank you and I will respond here if we get anywhere with physical analysis. ... View more

Hi, thank you for a quick response. Here's some ansewers for your questions inline: 1- What's the failure rate ? How many devices have you built with no issues ? We have made quite a bit of devices with this sensor but we haven't seen bigger problems with sensor on those (probably around 1k). However just recently we started making some proper long-term testing and currently we have exactly 3 devices that are failing. I think very important thing is that every board is validated after production (including bmp280) and this sensor stoped working after few days of long-term test on  3 out of 6 total. Right new we have another 4 setup with lon term tests with brand new sensors and try to replicate the behavior. The one thing that I can think of what have changed is that we have bumped the driver revision from v2.0.5 to v3.2.0 2- How is the device mounted/operated, etc. Anything special like moisture, vibrations, or shocks that could damage it ? The device was tested  in office environment. No moisture, vibrations or shocks as they were laying on test area and were not moved or touched. No excessive light either. Devices are connected to bench power supply and without any enclosures. 3- Have you tried with SPI communication ? Haven't tried yet mostly that our hardware does not allow it - SDO is shorted to GND to ensure 0x76 address. If you think it's worth to try I could possibly try to take it out of the system and handsolder it to one of the SPIs. If you idea here is that the interface has changed to SPI somehow (short of CS to ground) I have also checked if the address didn't change from 0x76 to 0x77, but without luck. Also in our design if there would be a short of CS to ground it would consume lot's of power as it's directly connected to 3v3. 4- Is the device drawing an unusually large amount of current ? Nothing large. I assume BMP280 would enter sleep mode after it's powered. We have a low power demo made for our device and the current seems around normal (159uA from 139uA typical for this setup) 5- Do you see physical damage under the microscope ? Sensor seems like brand new, no dents or nicks ... View more