英特尔MCS-51、MCS-48微控制器的振荡器的设计

CONTENTS PAGE
INTRODUCTION  1
FEEDBACK OSCILLATORS  1
Loop Gain  1
How Feedback Oscillators Work  2
The Positive Reactance Oscillator  2
QUARTZ CRYSTALS  3
Crystal Parameters  3
Equivalent Circuit  3
Load Capacitance  4
``Series'' vs. ``Parallel'' Crystals  4
Equivalent Series Resistance  4
Frequency Tolerance  5
Drive Level  5
CERAMIC RESONATORS  5
Specifications for Ceramic Resonators  6
OSCILLATOR DESIGN
CONSIDERATIONS  6
On-Chip Oscillators  6
Crystal Specifications  6
Oscillation Frequency  7
Selection of CX1 and CX2  7
Placement of Components  7
Clocking Other Chips  7
External Oscillators  8
Gate Oscillators vs. Discrete Devices  10
Fundamental vs. Overtone
Operation  11
``Series'' vs. ``Parallel'' Operation  11
CONTENTS PAGE
MORE ABOUT USING THE ``ON-CHIP''
OSCILLATORS  11
Oscillator Calculations  11
Start-Up Characteristics  13
Steady-State Characteristics  15
Pin Capacitance  16
MCSÉ-51 Oscillator  16
MCSÉ-48 Oscillator  16
CONTENTS PAGE
Pre-Production Tests  19
Troubleshooting Oscillator Problems  20
APPENDIX A: QUARTZ AND CERAMIC
RESONATOR FORMULAS  A-1
APPENDIX B: OSCILLATOR ANALYSIS
PROGRAM  B-1