LM3S1150-IQC50 Luminary Micro, Inc., LM3S1150-IQC50 Datasheet - Page 405

• Manufacturer Part Number: LM3S1150-IQC50
• Description: Microcontroller
• Manufacturer: Luminary Micro, Inc.

17
17.1
June 14, 2007
Quadrature Encoder Interface (QEI)
QEI
A quadrature encoder, also known as a 2-channel incremental encoder, converts linear displacement
into a pulse signal. By monitoring both the number of pulses and the relative phase of the two signals,
you can track the position, direction of rotation, and speed. In addition, a third channel, or index
signal, can be used to reset the position counter.
The Stellaris
quadrature encoder wheel to integrate position over time and determine direction of rotation. In
addition, it can capture a running estimate of the velocity of the encoder wheel.
The Stellaris
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Block Diagram
Figure 17-1 on page 406 provides a block diagram of a Stellaris
Position integrator that tracks the encoder position
Velocity capture using built-in timer
Interrupt generation on:
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Index pulse
Velocity-timer expiration
Direction change
Quadrature error detection
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quadrature encoder interface (QEI) module interprets the code produced by a
quadrature encoder has the following features:
Luminary Micro Confidential-Advance Product Information
®
QEI module.
LM3S1150 Microcontroller
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