LM628/LM629 Precision Motion Controller
November 1999
LM628/LM629
Precision Motion Controller
General Description
The LM628/LM629 are dedicated motion-control processors
designed for use with a variety of DC and brushless DC
servo motors, and other servomechanisms which provide a
quadrature incremental position feedback signal. The parts
perform the intensive, real-time computational tasks required
for high performance digital motion control. The host control
software interface is facilitated by a high-level command set.
The LM628 has an 8-bit output which can drive either an
8-bit or a 12-bit DAC. The components required to build a
servo system are reduced to the DC motor/actuator, an in-
cremental encoder, a DAC, a power amplifier, and the
LM628. An LM629-based system is similar, except that it
provides an 8-bit PWM output for directly driving H-switches.
The parts are fabricated in NMOS and packaged in a 28-pin
dual in-line package or a 24-pin surface mount package
(LM629 only). Both 6 MHz and 8 MHz maximum frequency
versions are available with the suffixes -6 and -8, respec-
tively, used to designate the versions. They incorporate an
SDA core processor and cells designed by SDA.
Features
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32-bit position, velocity, and acceleration registers
Programmable digital PID filter with 16-bit coefficients
Programmable derivative sampling interval
8- or 12-bit DAC output data (LM628)
8-bit sign-magnitude PWM output data (LM629)
Internal trapezoidal velocity profile generator
Velocity, target position, and filter parameters may be
changed during motion
Position and velocity modes of operation
Real-time programmable host interrupts
8-bit parallel asynchronous host interface
Quadrature incremental encoder interface with index
pulse input
Available in a 28-pin dual in-line package or a 24-pin
surface mount package (LM629 only)
DS009219-1
FIGURE 1. Block Diagram
TRI-STATE
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© 1999 National Semiconductor Corporation
DS009219
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