atxmega128a4-mu ATMEL Corporation, atxmega128a4-mu Datasheet - Page 13

• Manufacturer Part Number: atxmega128a4-mu
• Description: Atxmega16a4 8/16-bit Avr Xmega Microcontroller
• Manufacturer: ATMEL Corporation

10. System Clock and Clock options
10.1
10.2
8069A–AVR–02/08
Features
Overview
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XMEGA A4 has an advanced clock system, supporting a large number of clock sources. It incor-
porates both integrated oscillators, and external crystal oscillators and resonators. A high
frequency Phase Locked Loop (PLL) and clock prescalers can be controlled from software to
generate a wide range of clock frequencies. The clock distribution also enables the possibility to
switch between clock sources from software during run-time. A calibration feature (DFLL) is
available, and can be used for automatic run-time calibration of the internal oscillators. A Crystal
Oscillator Failure Monitor can be enabled to issue a Non-Maskable Interrupt and switch to inter-
nal oscillator if the external oscillator fails.
system in XMEGA A4.
Fast start-up time
Safe run time clock switching
4 Internal Oscillators; 32 MHz, 2 MHz, 32 kHz, 32 kHz Ultra Low Power (ULP)
0.4 - 16 MHz Crystal Oscillator, 32 kHz Crystal Oscillator, external clock
PLL with internal and external clock options and 1 to 31x multiplication
Clock Prescalers with 1 to 2048x division
Fast peripheral clock.
Automatic Run-Time Calibration of internal oscillators
Crystal Oscillator failure detection
Figure 10-1 on page 14
shows the principal clock
ATxmega A4
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