BHI260 - FIFO data format - descriptor and block header issues

[btruden_henway]

Hi, 

I'm working with a BHI260 chip and now I'm developing the FIFO reading feature on my host device which communicates to the BHI over SPI.

Issue 1

Based on the chip's datasheet section 14 (FIFO Data Formats), after getting the FIFO length I'm supposed to get the delta timestamp. According to the datasheet the delta timestamp it's all filled with zeros (16 bits).

I'm getting the following:

Am I missing something?

Issue 2

Again, based on the chip's datasheet section 14 (FIFO Data Formats), in the Block Header and after the "Spacer" Meta Event I'm supposed to get a full timestamp 40 bits of length (5 Bytes).

But in my case I see that the timestamp is 48 bits length (6 Bytes):

Am I missing something?

Thanks!

[BSTRobin]

Hello btruden_henway,

We would like to know some information from you first.
1. Did you use BHI160AB or other sensor part?
2. Which driver and FW you used?
3. Could we know your application code?

[btruden_henway]

Hi Robin,

1) Yes, I use the BHI160AB.

2) I'm using the firmware Bosch_SHUTTLE_BHI260.fw (RAM image). What do you mean by the driver? the one that is running on the host MCU? If that's the question the driver running on the host MCU was entirely written by me.

3) Application code (the driver running on the host MCU): https://drive.google.com/file/d/1h9p5VOSGRplQwA7WTCoEJ5FSb

Thanks!

[BSTRobin · Accepted solution]

Hello btruden_henway,

1.Please refer the delta timestamp format in Table79: Overview of FIFO Event IDs in BHI260 datasheet. From the wave in SPI bus, the delta timestamp is 0xF4 0x00 where 0xF4 is the wake-up Timestamp Small Delta ID and 0x00 is the value.

2.With the above table, we can see the Full Timestamp has 6 bytes in FIFO including the event ID. In the SPI wave, 0xF7 is the wake-up FIFO event ID of full timestamp and the following 5 bytes are timestamp value.

[btruden_henway]

Excellent! thanks!