For LPC11U68, you want to use the LPCOpen package for LPC11U68, not code bundles for the older (and different) LPC11U1x/2x/3x parts.
If you are using LPCXpresso IDE, these are includes in the Examples subdirectory of your IDE install. For other toolchains, you can download from: LPCOpen Libraries and Examples|NXP
Regards,
LPCXpresso Support