BNO055 peripheral init error problem and BL

Hi.

I have an issue with the Bosch BNO055 chip, where I am receiving an peripheral initialisation error. Pin 10 is connected to GND in my PCB design per the earlier datasheet I used linked from a supplier website (doh!), where this pin was changed to BL_IND, and output in recent revisions of the datasheet. I am not using the bootloader - just running the chip normally.

I need to know if the BL_IND being connected to GND will cause the register SYS_ERR (0x3A) to respond with error code 0x01 (peripheral initialisation error). I can write and read to and from the chip using i2c without issues, but all the readings from the sensors are 0x00. I suspect these zero readings are due to the the peripheral initialisation error. Unfortunately this issue is very urgent. Any help much appreciated.

I could cut the ground trace from pin 10, but unfortunately the track is under the pin. I would have to remove the chip and resolder it - a very difficult thing to do and I opnly have two prototype boards here. So I would like to know in this pin 10 is just benign if I am not using the bootlloader (ie: output never high) and is thus not the cause of the peripheral initialisation error. Also what could cause the perihperal initialisation error?

regards,
David

2014 datasheet.jpg

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Peripheral Init Error.png

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BNO055 schematic.jpg

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Hi.

I found the cause of the error! I had inherited some legacvy sphegetti code and in it they had defaulted to sleep mode. I can now read the acc, gyro and other data no problem, despite the "incorrect" wiring of pin 10 (and pins 15 and 16).

This does raise the question though as to why Bosch thought it was a good idea to change pinouts but provide scant infomration about the changes on 15, 16 and pins 10. Obviously I thought connecting an output (pin 10) to ground was a cause of the issue, but it wasn't. I will remove pins 10, 15 and 16 from ground in the next revision.

Bosch should consdier providing a techncal note clarifying the wiring compatibility of these pins 10, 15 and 16 between brounding and leaving them open.

Also, Bosch's factory lead time of 38 weeks on these chips shows Bosch is a high risk vendor. Such lead times are grossly inadequate in this day and age. Designers will abandon Bosch and look for alternative solutions from competitors. You cannot design when you cannot even get samples from Digikey and Mouser. Fortunately, my PCBs were made a few months ago, so I have 10 chips. Still, I have zero confidence in Bosch being able to provide these chips this year, or even in 2022.

BNO055 peripheral init error problem and BL_IND