we have a working board with the BNO085, but unfortunately the last time we ordered the BNO085 was not available, so we mounted the BNO055.
We want to communicate via Uart, because the SPI is not available on the BNO055. But unfortunately there is no sign/output from the BNO055, even the TX line stays low. PS1 is high, PS0 is low.
When we start the IC in bootloader mode, the TX line goes high.
The pins 15 and 16 are open.
In the old datasheet they are tied to GND, in the new one they are not connected.
Do you have any idea ?
Is there a way to upgrade the FW ?
Please refer the latest BNO055 data sheet and reference design.
The latest BNO055 can be found at the link: https://www.bosch-sensortec.com/media/boschsensortec/downloads/development_desktop_software/v3_24/de...
And this is a BNO patch for dd2.0, when you install the patch, the firmware in the dd2.0 would be updated. You can try with the new FW to see the version. More details can be found in this link: https://community.bosch-sensortec.com/t5/MEMS-sensors-forum/BNO055-Software-Version/td-p/14001
Please note that the product has been PDN (Product Discontinuation Notice), not recommended for new design. You could select other product, such as BHI160, BHI260 according your application.
thank you for your answer. I just downloaded the software and connected our board to the PC with a usb/uart bridge.
The BNO is started in bootloader mode.
Sniffing the Uart data with the oscilloscope I can see that the PC sends
0xaa 0x06 0x02 0x1f 0x0d 0x0a and
0xaa 0x06 0xB2 0x04 0x0d 0x0a
The BNO055 only responds with 0x6E ('n'), but at least there is a sign from the BNO and its TX line is high in idle state.
What could be the problem? Why is the TX line low if it was not started in the bootloader?
Is there a FW issue ?
Thanks a lot
How to upgrade the FW:
1. The Development Desktop UI provided by BST includes the BNO055 FW upgrade function by default. You can use it to upgrade the BNO055 at your side, refer document "C:\Program Files\Bosch Sensortec\Development Desktop 2.0\DD2.0_BMX055.pdf".
2. Adding the FW upgrade capability on your own board.