Dear Li YiFan

I only have the module, not the development kit.

Best regards

So finally I can confirm it was a firmware issue.
Since I updated the SPI-Connection seems working .

For everyone who may have the same problem:
Read this Topic carefully:
https://forum.aceinna.com/topic/93/top-topics-of-common-operations-with-openimu-products
If you wanna upgrade the FW by using a STLink (but no Serial-connection) make sure you hit the right start adress!

Dear all,

Currently I'm trying to get an SPI connection to an OpenIMU300ZI. Unfortunetally it always fails switching to SPI-Mode. It still stays in the UART mode. I verified the signals right on the pins.

1. Power on all components on my external board (supply for IMU depends on this board). Pin 7 connected by 10k to Vcc of bord
2. nRST = 0
3. Set up SPI-Connection of external board
4. Delay 50 ms
5. nRST = 1
6. Delay 750 ms (t_Reset_delay)

But after this procedure I still have the serial communication on the SCK channel (of course with wrong level). Checking the signal by an oscilloscope shows that (as I would expect for the serial communication) with 0x55 0x55, followed by some other values (@ 115200 baud).

Now my Question is:
Are there older units which does not support the SPI in the default firmare? My unit is: P/N 8350-3885-02, barcode: 1908400355. I bought it arround two or three weeks ago on mouser.

I would appreciat your answer, best regards
Jérôme