Hi markj,
Thanks for your inquiry.
We suggest that you use a logic analyzer to capture SPI hardware waveforms, which can show the actual host accessing SPI data of BMI 270 and the delay during communication. Instead of observing through printing information, as printing itself can cause delays. Additionally, from your print information, it appears that some registers are not used on the data sheet of BMI270, such as registers 0xA1, 0xB0, etc. in your print information. This requires checking if your code or printing is correct.
Additionally, I have attached the waveform of BMI270 SPI communication captured through Saleae for your reference.
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