Hi Nicolaj,
big thanks for response, it works now. Your first line was the solution:
It seems in case of not use any of the SPI-Enable signals the SPI runs only in MultiChannel mode.
(LSB in MCSPI1_MODULCTRL cleared). Due to I use only one channel I enabled Singe channel mode.
Big mistake.
I did not found any explanation for this in the manual. (Any background information TI staff?)
Best regards