Need Technical Support on - BNO055 - Difference between silk print A6 and A9
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Thanks for your reply.
We ordered 501PCs in May-2021 at very high unit price from a local web shop (www.icsuns.com)
We contacted with them for the issues already, but they
The silk screen of the chip we received is A6, not A9, We already contacted them for this problem.
but they now claim that the silk screen of the chip sold to us is A9, not A6.
If you can help us recover the payment, we would be very grateful.
For the detailed pehnomonon is the IMU doesn't work at all, all 500PCs not work!
After change A6 chip to A9, then the board can work normally.
Below reports is from my colleagues:
After i further focused on the i2c communication between the uC and the imu, i figured the following:
- The Chip(BNO055) isn't responding to its I2C Address (0x28), nor to its second Address (0x29), screenshots attached.
- The I2C Bus voltage levels are correct and the pullup resistor values are also fine
- I2C timings / frequencies are identical to the ones from the last working batch of pcbas (measured / compared them).
- After probing through the whole address range i figured that the bno055 is responding to i2c address (0x48), also able to reliably read some register values then.
Which is kind wierd, because this address isn't listed in any of the documentation. But maybe i'm missing smt. here.
- Unfortunately i'm not able to check the solder joints of this bga chip, as they're right below the chip.
We definitly need to get this sorted quickly, as we currently aren't able to use these pcbas.
Thank you very much again.