BMG250 not communicating

[Libero]

I have one of your BMG250 gyros on a PCB with other devices, all of which are connected via an SPI bus. I can communicate with all the other devices and the MISO line changes state as expected. When I try to read data from the BMG250 all I get is 0xFF irrespective of which address I am trying to access. The CS is not clashing with the CS of other devices and powr is applied. As specified on your datasheet, I start off with a read of address 0x7F, and even toggled the CS line to ensure the device switches to SPI mode. The signals into the device appear to be correct with all the timings well within you specifications. I have two different devices on two different boards and they both do the same thing. As a test, I am trying to read the chip ID register. It is as though the device is not powered. Have I missed something obvious? Any suggestions?

[FAE_CA1]

Hi,

Thanks for your inquiry. BMG250 SPI interface should work fine. You may purchase a BMG250 shuttle board from https://www.mouser.com/ProductDetail/Bosch-Sensortec/BMG250-Shuttle-Board?qs=sGAEpiMZZMuqBwn8WqcFUj9... and then connect your MCU to the shuttle board through a breadboard to test the SPI communication.

BMG250 SPI interface supports mode 0 and mode 3. At the beginning, you can use your MCU GPIO pin to set CSB pin from high to low, and then from low to high. BMG250 will swtich from default I2C interface to SPI interface automatically. Then when you want to read BMG250 chip ID at register 0x00, you should write value of 0x80 to SPI address for reading after you set CSB pin to low. Then you write value of 0xFF to SPI to issue another 8 pulses of clock. You should get the value of 0xD5 back from BMG250. Then you set CSB pin to high to finish this SPI single byte reading transaction.

Hope it helps. Thanks.

[Libero]

Thank-you for your reply.  I am already doing all you suggested, however there is no communication from the device.  Please see attached file.

[FAE_CA1]

Hi,

I don't see your attached file. Could you please let us know your email address so that we can support you offline?

Thanks.

[Vincent]

Sorry, there is no attachment found in your post.

Please share your schematic around BMG250 and also the voltage level you measured on sensor VDD and VDDIO pin on your board.