Set up the PLL/Clock in the start-up file ("Startup.s")in assembly language. I used:
LDR R0, =MMR_BASE MOV R1, #0xAA STR R1, [R0,#PLLKEY1_OFFSET] MOV R1, #PLLCON_Val STR R1, [R0,#PLLCON_OFFSET] MOV R1, #0x55 STR R1, [R0,#PLLKEY2_OFFSET]
This seems to do the trick!