Check SystemCoreClockUpdate() Output

Discussion created by lpcware Employee on Jun 15, 2016
Content originally posted in LPCWare by mohammadyou on Sat Oct 31 01:29:05 MST 2015
I have Chosen MSEL=0x000B [11+1 =12 -> 0x000C], NSEL=0x0000 [0+1=1 -> 0x0001], CCLKSEL=0x0002 [2+1=3 -> 0x0002] and enable Main Oscillator [12 Mhz - and also set it in the "options for target" ] . it is supposed we have 96 Mhz based on the datasheet of LPC1768 [Calculated with the Excel form] 
During the debugging when I want to check the output of  SystemCoreClockUpdate() function in Watch window it gives me the number 0x00000348 [840] !!!
When I check the output of Peripherals  -> clocking & power control -> clock generation schematic during debug time. it gives me the correct frequency !!! (96 mhz)