The LPC3250 can operate in three modes. If the device is in RUN mode, it indicates that the application needs the CPU, AHB bus, or one of the peripherals that runs faster than SYSCLK. In this mode, the CPU will run typically at 266 MHz and the AHB bus would run at 133 MHz. In the DIRECT RUN mode, the running application does not need the CPU, the AHB bus, and the peripherals to run faster than SYSCLK. This is the default mode after chip reset.