Hello,
I did not know you use SDK based project. Unfortunately, this project use different header file and it is not recommended to use your own header file. Please delete your header file and please use following way, how to access registers:
/*Set SRC = 3, OBE = 1 and SSS = 1 */
SIUL2->MSCR[37] = 0x32000001;
or you can use included macros. The same result as the code above:
SIUL2->MSCR[37] = SIUL2_MSCR_SSS(1)| SIUL2_MSCR_OBE(1) | SIUL2_MSCR_SRC(3);
Regards,
Martin