Atmel Xplained Pro Evaluation Kit for the ATSAMD21J18A Microcontroller ATSAMD21-XPRO ATSAMD21-XPRO Data Sheet
Product codes
ATSAMD21-XPRO
138
Atmel | SMART SAM D21 [DATASHEET]
Atmel-42181C–SAM-D21_Datasheet–07/2014
16.
SYSCTRL – System Controller
16.1 Overview
The System Controller (SYSCTRL) provides a user interface to the clock sources, brown out detectors, on-chip voltage
regulator and voltage reference of the device.
regulator and voltage reference of the device.
Through the interface registers, it is possible to enable, disable, calibrate and monitor the SYSCTRL sub-peripherals.
All sub-peripheral statuses are collected in the Power and Clocks Status register (PCLKSR - refer to
). They can
additionally trigger interrupts upon status changes via the INTENSET (
INTFLAG (
) registers.
Additionally, BOD33 interrupts can be used to wake up the device from standby mode upon a programmed brown-out
detection.
detection.
16.2 Features
z
0.4-32MHz Crystal Oscillator (XOSC)
z
Tunable gain control
z
Programmable start-up time
z
Crystal or external input clock on XIN I/O
z
32.768kHz Crystal Oscillator (XOSC32K)
z
Automatic or manual gain control
z
Programmable start-up time
z
Crystal or external input clock on XIN32 I/O
z
32.768kHz High Accuracy Internal Oscillator (OSC32K)
z
Frequency fine tuning
z
Programmable start-up time
z
32.768kHz Ultra Low Power Internal Oscillator (OSCULP32K)
z
Ultra low power, always-on oscillator
z
Frequency fine tuning
z
Calibration value loaded from Flash Factory Calibration at reset
z
8MHz Internal Oscillator (OSC8M)
z
Fast startup
z
Output frequency fine tuning
z
4/2/1MHz divided output frequencies available
z
Calibration value loaded from Flash Factory Calibration at reset
z
Digital Frequency Locked Loop (DFLL48M)
z
Internal
oscillator with no external components
z
48MHz output frequency
z
Operates standalone as a high-frequency programmable oscillator in open loop mode
z
Operates as an accurate frequency multiplier against a known frequency in closed loop mode
z
Fractional Digital Phase Locked Loop (FDPLL96M)
z
48MHz to 96MHz output clock frequency
z
32KHz to 2MHz input reference clock frequency range
z
Three possible sources for the reference clock
z
Adjustable proportional integral controller
z
Fractional part used to achieve 1/16th of reference clock step
z
3.3V Brown-Out Detector (BOD33)
z
Programmable threshold
z
Threshold value loaded from Flash User Calibration at startup
z
Triggers resets or interrupts
z
Operating modes:
z
Continuous mode