software in the device. The device can thus be shipped to end customers, who will be
able to program their own code into the device to access the secure libraries, but without risk ofcompromising the proprietary secure code.
The External Interrupt Controller (EIC) allows pins to be configured as external interrupts. Eachexternal interrupt has its own interrupt request and can be individually masked.The Peripheral Event System allows peripherals to receive, react to, and send peripheral eventswithout CPU intervention. Asynchronous interrupts allow advanced peripheral operation in lowpower sleep modes.
The Power Manager (PM) improves design flexibility and security. The Power Manager supportsSleepWalking functionality, by which a module can be selectively activated based on peripheralevents, even in sleep modes where the module clock is stopped. Power monitoring is supportedby on-chip Power-on Reset (POR), Brown-out Detector (BOD), and Supply Monitor (SM). The
device features several oscillators, such as Digital Frequency Locked Loop (DFLL), Oscillator 0(OSC0), and system RC oscillator (RCSYS). Either of these oscillators can be used as sourcefor the system clock. The DFLL is a programmable internal oscillator from 40 to 150MHz. It can
be tuned to a high accuracy if an accurate refernce clock is running, e.g. the 32KHz crystaloscillator.The Watchdog Timer (WDT) will reset the device unless it is periodically serviced by the software.This allows the device to recover from a condition that has caused the system to beunstable.The Asynchronous Timer (AST) combined with the 32KHz crystal oscillator supports powerful
real-time clock capabilities, with a maximum timeout of up to 136 years. The AST can operate incounter mode or calendar mode.