Regarding the power management controller on the SAM3U, it’s important to note that at start up the 32 kHz RC and the 4 MHz RC are enabled by default. Contrary to SAM7 products, boot at reset will not occur at 32 kHz on the slow clock. Instead, boot will occur from the fast 4 MHz RC oscillator. This means that after reset, the processor clock and the different peripherals will run at up to 4 MHz. A new feature on the SAM3U useful for debug purposes is the possibility to output on a dedicated pin, programmable clock pin or PCK. This outputs the master clock of the system, so it is possible for debug to check which clock frequency the customer is running on.