lpc1765 NXP Semiconductors, lpc1765 Datasheet - Page 27

• Manufacturer Part Number: lpc1765
• Description: 32-bit Arm Cortex-m3 Microcontroller Up To 512 Kb Flash And 64 Kb Sram With Ethernet, Usb 2.0 Host/device/otg, Can
• Manufacturer: NXP Semiconductors

NXP Semiconductors
LPC1768_66_65_64_2
Objective data sheet
7.24.1 Features
7.23 Motor control PWM
7.24 Quadrature Encoder Interface (QEI)
The motor control PWM is a specialized PWM supporting 3-phase motors and other
combinations. Feedback inputs are provided to automatically sense rotor position and use
that information to ramp speed up or down. An abort input is also provided that causes the
PWM to immediately release all motor drive outputs. At the same time, the motor control
PWM is highly configurable for other generalized timing, counting, capture, and compare
applications.
A quadrature encoder, also known as a 2-channel incremental encoder, converts angular
displacement into two pulse signals. By monitoring both the number of pulses and the
relative phase of the two signals, the user can track the position, direction of rotation, and
velocity. In addition, a third channel, or index signal, can be used to reset the position
counter. The quadrature encoder interface decodes the digital pulses from a quadrature
encoder wheel to integrate position over time and determine direction of rotation. In
addition, the QEI can capture the velocity of the encoder wheel.
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Pulse period and width can be any number of timer counts. This allows complete
flexibility in the trade-off between resolution and repetition rate. All PWM outputs will
occur at the same repetition rate.
Double edge controlled PWM outputs can be programmed to be either positive going
or negative going pulses.
Match register updates are synchronized with pulse outputs to prevent generation of
erroneous pulses. Software must ‘release’ new match values before they can become
effective.
May be used as a standard 32-bit timer/counter with a programmable 32-bit prescaler
if the PWM mode is not enabled.
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 (clk and direction).
Connected to APB.
Rev. 02 — 11 February 2009
32-bit ARM Cortex-M3 microcontroller
LPC1768/66/65/64
© NXP B.V. 2009. All rights reserved.
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