Dear Li YiFan
I only have the module, not the development kit.
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:
If you wanna upgrade the FW by using a STLink (but no Serial-connection) make sure you hit the right start adress!
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.
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