UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
893 of 1269
31.1 How to read this chapter
The QEI is available on all LPC435x/3x parts.
31.2 Basic configuration
The QEI is configured as follows:
•
See
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 Features
This 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 and
partial revolution displacement.
•
Digital filter with programmable delays for encoder input signals.
•
Can accept decoded signal inputs (clock and direction).
UM10503
Chapter 31: LPC43xx Quadrature Encoder Interface (QEI)
Rev. 1.3 — 6 July 2012
User manual
Table 722. QEI clocking and power control
Base clock
Branch clock
Operating
frequency
Clock to the QEI register interface and QEI
peripheral clock.
BASE_M4_CLK
CLK_M4_QEI
up to
204 MHz
