Content originally posted in LPCWare by daniel.widyanto on Fri Sep 28 00:34:00 MST 2012
Refer to CMSISv2p00_LPC13xx package (from LPCXpresso example directory: C:\nxp\LPCXpresso_4.2.3_292\lpcxpresso\Examples\NXP\LPC1000\LPC13xx or within the demo project that you use). See the 'SystemInit()' function under 'system_LPC13xx.c' for clock settings and system initialization
SystemCoreClockUpdate() is referring to updating global variable 'SystemCoreClock' with the current core's speed