NXP Semiconductors LPC43 Series User Manual

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NXP Semiconductors LPC43 Series User Manual Manual pdf 893 page image

UM10503 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2012. All rights reserved.User manual Rev. 1.3 — 6 July 2012 893 of 126931.1 How to read this chapterThe QEI is available on all LPC435x/3x parts.31.2 Basic configurationThe QEI is configured as follows:• See Table 722 for clocking and power control.• The QEI is reset by the QEI_RST (reset #39).• The QEI interrupt is connected to slot # 15 in the Event router.31.3 FeaturesThis Quadrature Encoder Interface (QEI) has the following features:• Tracks encoder position.• Increments/ decrements depending on direction.• Programmable for 2X or 4X position counting.• Velocity capture using built-in timer.• Velocity compare function with less than interrupt.• Uses 32-bit registers for position and velocity.• Three position compare registers with interrupts.• Index counter for revolution counting.• Index compare register with interrupts.• Can combine index and position interrupts to produce an interrupt for whole andpartial revolution displacement.• Digital filter with programmable delays for encoder input signals.• Can accept decoded signal inputs (clock and direction).UM10503Chapter 31: LPC43xx Quadrature Encoder Interface (QEI)Rev. 1.3 — 6 July 2012 User manualTable 722. QEI clocking and power controlBase clock Branch clock OperatingfrequencyClock to the QEI register interface and QEIperipheral clock.BASE_M4_CLK CLK_M4_QEI up to204 MHz