LM3S9792 Datasheet, PDF (64/1279 Pages) Texas Instruments – Stellaris® LM3S9792 Microcontroller

Architectural Overview
1.1.6.2
1.1.7
■ Synchronization of timers in the PWM generator blocks
■ Synchronization of timer/comparator updates across the PWM generator blocks
■ Synchronization of PWM output enables across the PWM generator blocks
■ Interrupt status summary of the PWM generator blocks
■ Extended fault capabilities with multiple fault signals, programmable polarities, and filtering
■ PWM generators can be operated independently or synchronized with other generators
QEI (see page 1102)
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,
the position, direction of rotation, and speed can be tracked. In addition, a third channel, or index
signal, can be used to reset the position counter. The Stellaris^® quadrature encoder with index (QEI)
module interprets the code produced by a 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 input frequency of the QEI inputs may be as high as 1/4 of the processor
frequency (for example, 20 MHz for a 80-MHz system).
The LM3S9792 microcontroller includes two QEI modules providing control of two motors at the
same time with the following features:
■ Position integrator that tracks the encoder position
■ Programmable noise filter on the inputs
■ Velocity capture using built-in timer
■ The input frequency of the QEI inputs may be as high as 1/4 of the processor frequency (for
example, 12.5 MHz for a 50-MHz system)
■ Interrupt generation on:
– Index pulse
– Velocity-timer expiration
– Direction change
– Quadrature error detection
Analog
The LM3S9792 controller provides analog functions integrated into the device, including:
■ Two 10-bit Analog-to-Digital Converters (ADC) with sixteen analog input channels and sample
rate of one million samples/second
■ Three analog comparators
■ 16 digital comparators
■ On-chip voltage regulator
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June 14, 2010
Texas Instruments-Advance Information