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Selecting and Testing 32.768 kHz Crystal Oscillators for AVR® Microcontrollers AN2648
Introduction
Features
1 Crystal Oscillator Basics
1.1 Introduction
1.2 The Oscillator
1.3 Electrical Model
1.4 Equivalent Series Resistance (ESR)
1.5 Q-Factor and Stability
1.6 Start-Up Time
1.7 Temperature Tolerance
1.8 Drive Strength
2 PCB Layout and Design Considerations
3 Testing Crystal Oscillation Robustness
3.1 Introduction
3.2 Negative Resistance Test and Safety Factor
3.3 Measuring Effective Load Capacitance
4 Test Firmware
5 Crystal Recommendations
6 Oscillator Module Overview
6.1 megaAVR® Devices
6.2 tinyAVR® Devices
6.3 AVR® Dx Devices
6.4 AVR® XMEGA® Devices
7 Revision History
Microchip Information
The Microchip Website
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Microchip Devices Code Protection Feature
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