ATmega32U2 datasheet(32/314 Pages) ATMEL

Part #	ATmega32U2

Description	8-bit Microcontroller with 8/16/32K Bytes of ISP Flash and USB Controller

PDF	314 Pages

Scroll/Zoom	100%

Manufacturer	ATMEL [ATMEL Corporation]

Direct Link	http://www.atmel.com

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32 / 314 page

7799B–AVR–07/09

ATmega8U2/16U2/32U2

8.5

Full Swing Crystal Oscillator

Pins XTAL1 and XTAL2 are input and output, respectively, of an inverting amplifier which can be

configured for use as an On-chip Oscillator, as shown in Figure 8-4. Either a quartz crystal or a

ceramic resonator may be used.

This Crystal Oscillator is a full swing oscillator, with rail-to-rail swing on the XTAL2 output. This is

useful for driving other clock inputs and in noisy environments. The current consumption is

higher than the “Low Power Crystal Oscillator” on page 30. Note that the Full Swing Crystal

Oscillator will only operate for V

CC = 2.7 - 5.5 volts.

C1 and C2 should always be equal for both crystals and resonators. The optimal value of the

capacitors depends on the crystal or resonator in use, the amount of stray capacitance, and the

electromagnetic noise of the environment. Some initial guidelines for choosing capacitors for

use with crystals are given in Table 1. For ceramic resonators, the capacitor values given by the

manufacturer should be used.

ATmega32U2 Datasheet(PDF) 32 Page - ATMEL Corporation