How to write to SHPR2 correctly on cortex M0

Question

What is wrong with this code? When I debug it in DAVE4 with XMC1100 Boot Kit the SHPR2 register not changing in the debugger. The code is based on EasyMain (LED blinking is working for example with a modified main).

I have studied the DDI0419C_arm_architecture_v6m_reference_manual I think it should work.

#include "XMC1100.h"

int main(void)
{
 unsigned int a;

 a = 0x0B << PPB_SHPR2_PRI_11_Pos;
 PPB->SHPR2 |= a;

 while(1);
}

Answer 1

CMSIS functions should be used.