Datasheet

20
XMEGA D3 [DATASHEET]
Atmel-8134N-ATxmega32D3-64D3-128D3-192D3-256D3-384D3_datasheet–03/2014
Figure 9-1. The clock system, clock sources and clock distribution.
9.3 Clock sources
The clock sources are divided in two main groups: internal oscillators and external clock sources. Most of the clock
sources can be directly enabled and disabled from software, while others are automatically enabled or disabled,
depending on peripheral settings. After reset, the device starts up running from the 2MHz internal oscillator. The other
clock sources, DFLLs and PLL, are turned off by default.
The internal oscillators do not require any external components to run. For details on characteristics and accuracy of the
internal oscillators, refer to the device datasheet.
Real Time
Counter
Peripherals RAM AVR CPU
Non-Volatile
Memory
Watchdog
Timer
Brown-out
Detector
System Clock Prescalers
System Clock Multiplexer
(SCLKSEL)
PLLSRC
RTCSRC
DIV32
32kHz
Int. ULP
32.768kHz
Int. OSC
32.768kHz
TOSC
2MHz
Int. Osc
32MHz
Int. Osc
0.4 – 16MHz
XTAL
DIV32
DIV32
DIV4
XOSCSEL
PLL
TOSC1 TOSC2 XTAL1 XTAL2
clk
SYS
clk
RTC
clk
PER2
clk
PER
clk
CPU
clk
PER4