LM629N-8/NOPB National Semiconductor, LM629N-8/NOPB Datasheet - Page 18

• Manufacturer Part Number: LM629N-8/NOPB
• Description: IC CONTROLLER PREC MOTION 28-DIP
• Manufacturer: National Semiconductor

Specifications of LM629N-8/NOPB

• Applications: DC Motor Controller, Servo
• Number Of Outputs: 1
• Voltage - Supply: 4.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Through Hole
• Package / Case: 28-DIP (0.600", 15.24mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output: -
• Voltage - Load: -
• Other names: *LM629N-8; *LM629N-8/NOPB; LM629N-8

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Data Reporting Commands
divided by the incremental encoder resolution (encoder lines
times four), should always be an integral number. The RDIP
command facilitates acquiring these data for host-based
calculations. The command can also be used to identify/
verify home or some other special position. The bytes are
read in most-to-least significant order.
RDDP COMMAND: READ DESIRED POSITION
This command reads the instantaneous desired (current
temporal ) position output of the profile generator. This is the
“setpoint” input to the position-loop summing junction. The
bytes are read in most-to-least significant order.
RDRP COMMAND: READ REAL POSITION
This command reads the current actual position of the motor.
This is the feedback input to the loop summing junction. The
bytes are read in most-to-least significant order.
RDDV COMMAND: READ DESIRED VELOCITY
This command reads the integer and fractional portions of
the instantaneous desired (current temporal ) velocity, as
used to generate the desired position profile. The bytes are
read in most-to-least significant order. The value read is
properly scaled for numerical comparison with the user-
supplied (commanded) velocity; however, because the two
least-significant bytes represent fractional velocity, only the
two most-significant bytes are appropriate for comparison
with the data obtained via command RDRV (see below).
Also note that, although the velocity input data is constrained
to positive numbers (see command LTRJ), the data returned
by command RDDV represents a signed quantity where
negative numbers represent operation in the reverse direc-
tion.
RDRV COMMAND: READ REAL VELOCITY
This command reads the integer portion of the instanta-
neous actual velocity of the motor. The internally maintained
fractional portion of velocity is not reported because the
reported data is derived by reading the incremental encoder,
which produces only integer data. For comparison with the
result obtained by executing command RDDV (or the user-
supplied input value), the value returned by command RDRV
must be multiplied by 2
(Continued)
Command Code:
Bytes Read:
Data Range:
Executable During Motion: Yes
Command Code:
Bytes Read:
Data Range:
Executable During Motion: Yes
Command Code:
Bytes Read:
Data Range:
Executable During Motion: Yes
Command Code:
Bytes Read:
Data Range:
Executable During Motion: Yes
16
(shifted left 16 bit positions). Also,
08 Hex
Four
C0000000 to 3FFFFFFF Hex
0A Hex
Four
C0000000 to 3FFFFFFF Hex
07 Hex
Four
C0000001 to 3FFFFFFF
0B Hex
Two
C000 to 3FFF Hex, See Text
18
as with command RDDV above, data returned by command
RDRV is a signed quantity, with negative values represent-
ing reverse-direction motion.
RDSUM COMMAND: READ INTEGRATION-TERM
SUMMATION VALUE
This command reads the value to which the integration term
has accumulated. The ability to read this value may be
helpful in initially or adaptively tuning the system.
Typical Applications
PROGRAMMING LM628 HOST HANDSHAKING
(INTERRUPTS)
A few words regarding the LM628 host handshaking will be
helpful to the system programmer. As indicated in various
portions of the above text, the LM628 handshakes with the
host computer in two ways: via the host interrupt output (Pin
17), or via polling the status byte for “interrupt” conditions.
When the hardwired interrupt is used, the status byte is also
read and parsed to determine which of six possible condi-
tions caused the interrupt.
When using the hardwired interrupt it is very important that
the host interrupt service routine does not interfere with a
command sequence which might have been in progress
when the interrupt occurred. If the host interrupt service
routine were to issue a command to the LM628 while it is in
the middle of an ongoing command sequence, the ongoing
command will be aborted (which could be detrimental to the
application).
Two approaches exist for avoiding this problem. If one is
using hardwired interrupts, they should be disabled at the
host prior to issuing any LM628 command sequence, and
re-enabled after each command sequence. The second ap-
proach is to avoid hardwired interrupts and poll the LM628
status byte for “interrupt” status. The status byte always
reflects the interrupt-condition status, independent of
whether or not the interrupts have been masked.
TYPICAL HOST COMPUTER/PROCESSOR INTERFACE
The LM628 is interfaced with the host computer/processor
via an 8-bit parallel bus. Figure 12 shows such an interface
and a minimum system configuration.
As shown in Figure 12, the LM628 interfaces with the host
data, address and control lines. The address lines are de-
coded to generate the LM628 CS input; the host address
LSB directly drives the LM628 PS input. Figure 12 also
shows an 8-bit DAC and an LM12 Power Op Amp interfaced
to the LM628.
LM628 AND HIGH PERFORMANCE CONTROLLER
(HPC)INTERFACE
Figure 13 shows the LM628 interfaced to a National HPC
High Performance Controller. The delay and logic associated
with the WR line is used to effectively increase the write-data
hold time of the HPC (as seen at the LM628) by causing the
WR pulse to rise early. Note that the HPC CK2 output
Command Code:
Bytes Read:
Data Range:
Executable During Motion: Yes
0D Hex
Two
00000 Hex to
Value of the Integration Limit
±
the Current