Oregon Micro Systems PC46 family User manual

USER’S MANUAL
INTELLIGENT MOTOR CONTROLLERS
PC46 FAMILY
OREGON MICRO SYSTEMS, INC.
TWIN OAKS BUSINESS CENTER
1800 NW 169th PLACE, SUITE C100
BEAVERTON, OR 97006
PHONE [phone]
FAX [phone]
EMAIL [email protected]
WEB SITE www.OMSmotion.com

COPYRIGHT NOTICE
© 2001 Oregon Micro Systems, Inc., A Pro-Dex Company ALL RIGHTS RESERVED
This document is copyrighted by Oregon Micro Systems, Inc. You may not reproduce, transmit, transcribe, store
in a retrieval system, or translate into any language in any form or by any means, electronic, mechanical,
magnetic, optical, chemical, manual, or otherwise, any part of this publication without the express written
permission of Oregon Micro Systems, Inc.
TRADEMARKS
IBM, IBM PC, IBM PC/XT, IBM PC/AT, IBM PS/2 and IBM PC DOS are registered trademarks of International
Business Machines Corporation.
DISCLAIMER
Oregon Micro Systems, Inc. makes no representations or warranties regarding the contents of this document.
We reserve the right to revise this document, or make changes to the specifications of the product described
within it at any time without notice and without obligation to notify any person of such revision or change.
3301-0500000
Revision F

TABLE OF CONTENTS 1. GENERAL DESCRIPTION
PC46 User’s Manual i
TABLE OF CONTENTS
1. GENERAL DESCRIPTION
INTRODUCTION ............................................................................................. 1-1
FUNCTIONAL DESCRIPTION......................................................................... 1-1
VELOCITY PROFILES .................................................................................... 1-3
2. GETTING STARTED
INTRODUCTION ............................................................................................. 2-1
JUMPERS........................................................................................................ 2-2
HARDWARE INSTALLATION ......................................................................... 2-4
SOFTWARE INSTALLATION.......................................................................... 2-5
MOTOR CONTROL CONNECTOR ................................................................. 2-5
3. I/O CHANNEL INTERFACE
I/O CHANNEL.................................................................................................. 3-1
PC/AT DATA BUS................................................................................ 3-1
PC/AT ADDRESS BUS ........................................................................ 3-1
MEMORY AND I/O CONTROL............................................................. 3-1
INTERRUPT REQUEST....................................................................... 3-1
CLOCK AND OSC LINES .................................................................... 3-2
RESET DRV......................................................................................... 3-2
I/O CH RDY.......................................................................................... 3-2
I/O CH CK ............................................................................................ 3-2
ADDRESS SELECTION .................................................................................. 3-3
USING INTERRUPTS...................................................................................... 3-5
I/O REGISTERS .............................................................................................. 3-5
DATA REGISTER ................................................................................ 3-5
DONE FLAG REGISTER ..................................................................... 3-5
INTERRUPT CONTROL REGISTER ................................................... 3-6
STATUS REGISTER............................................................................ 3-6
POWER SUPPLY REQUIREMENTS............................................................... 3-7
4. DRIVER INTERFACE
OUTPUT CONNECTIONS............................................................................... 4-1
MULTI-AXIS SYNCHRONIZATION ................................................................. 4-4
LIMIT AND HOME LINES ................................................................................ 4-5
FUSED PROTECTION .................................................................................... 4-5
5. ENCODER OPTION
INTRODUCTION ............................................................................................. 5-1
MODES OF OPERATION................................................................................ 5-1
ENCODER SELECTION AND COMPATIBILITY ............................................. 5-1

TABLE OF CONTENTS 6. COMMAND STRUCTURE
PC46 User’s Manual
ii
ENCODER INTERFACE ..................................................................................5-1
HOME PROCEDURES.....................................................................................5-3
6. COMMAND STRUCTURE
INTRODUCTION..............................................................................................6-1
COMMAND QUEUES.......................................................................................6-2
COMMAND SUMMARY....................................................................................6-2
AXIS SPECIFICATION COMMANDS...............................................................6-6
SYSTEM CONTROL COMMANDS ................................................................6-10
USER I/O COMMANDS..................................................................................6-16
MOVE SPECIFICATION COMMANDS...........................................................6-21
MOVE EXECUTION COMMANDS .................................................................6-29
MOVE TERMINATION COMMANDS .............................................................6-33
LOOP CONTROL COMMANDS.....................................................................6-35
HOME AND INITIALIZATION CONTROL COMMANDS.................................6-40
MOVE SYNCHRONIZATION COMMANDS....................................................6-43
SYSTEM STATUS REQUEST COMMANDS..................................................6-49
USER UNIT COMMANDS ..............................................................................6-55
POSITION MAINTENANCE COMMANDS .....................................................6-56
SLIP AND STALL DETECTION COMMANDS................................................6-60
ENCODER TRACKING COMMANDS ............................................................6-62
ENCODER HOME CONTROL COMMANDS..................................................6-63
ENCODER STATUS REQUEST COMMANDS ..............................................6-64
VELOCITY STAIRCASE COMMANDS...........................................................6-66
CONSTANT VELOCITY CONTOURING........................................................6-69
7. HOST SOFTWARE
INTRODUCTION..............................................................................................7-1
PROGRAM FILES............................................................................................7-1
DRIVER SUPPORT..........................................................................................7-1
DEVICE DRIVER INSTALLATION........................................................7-1
COMMAND LINE OPTIONS .................................................................7-2
BOARD STATUS MESSAGE HANDLING ............................................7-3
OTHER DEVICE DRIVER FEATURES.................................................7-3
INTERFACING TO THE DEVICE DRIVER...........................................7-4
MULTIPLE BOARDS IN ONE COMPUTER..........................................7-6
8. SERVICE
USER SERVICE...............................................................................................8-1
THEORY OF OPERATION ..............................................................................8-1

TABLE OF CONTENTS A. LIMITED WARRANTY
PC46 User’s Manual iii
A. LIMITED WARRANTY
B. TECHNICAL INFORMATION / RETURN FOR REPAIR PROCEDURES
C. SPECIFICATIONS
INDEX

TABLE OF CONTENTS INDEX
PC46 User’s Manual
iv
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1. GENERAL DESCRIPTION INTRODUCTION
PC46 User’s Manual 1-1
1.
GENERAL DESCRIPTION
1.1. INTRODUCTION
The PC46 family of intelligent motion controls can manage as many as 6 axes of motion
in one I/O slot of a PC/AT or compatible computer. They meet the IBM I/O channel
specifications and can be plugged directly into the backplane of these machines. The
PC46-2E can, for example, simultaneously control two axes of step motors while monitor-
ing their actual position with the built in incremental encoder interface. It can manage
coordinated or independent motion on each of the four axes simultaneously.
The PC46 functions as a motion coprocessor within the PC/AT or compatible computer. It
utilizes a 68332 microprocessor and patented proprietary technology (patent number
4,734,847) to control direction of motion, acceleration, deceleration and velocity of an
associated motor. In response to commands from the host computer, the PC46 controller
will calculate the optimum velocity profile to reach the desired destination in the minimum
time while conforming to the programmed velocity and acceleration parameters.
The PC46 family of controllers, when combined with Oregon Micro Systems’ drivers, can
employ ‘microstepping’ techniques for increased position resolution and decreased low
speed resonance. When combined with the appropriate Oregon Micro Systems’ driver
and step motor, the normal step angle can be divided into as many as 128 microsteps per
step.
Commands may be sent to the PC46 by simple I/O commands using virtually any
language on the PC which has the ability to do I/O. It is easily programmed using ASCII
character strings. For a typical motion requirement of 1,000,000 pulses at 400,000
pulses/sec and an acceleration of 500,000 pulses/sec2the following string would be sent
from the host computer to the PC46:
VL400000 AC500000 MR1000000 GO
For additional programming examples see Section 6.
1.2. FUNCTIONAL DESCRIPTION
The PC46, in response to commands from the host computer, provides controlled
acceleration to a predefined peak speed followed by a constant velocity and controlled
deceleration to a stop. This is achieved by calculating the optimum velocity 1024 times
each second (512 times each second on the PC46-21 and PC46-41 models), providing a
very smooth acceleration curve. This calculation is used to control a variable frequency
pulse train which is derived from a crystal oscillator providing very accurate pulse rates.
The 68332 microprocessor calculates this velocity profile for each of the axes providing
independent but synchronized (if desired) profiles for each axis. The PC46 can perform a

FUNCTIONAL DESCRIPTION 1. GENERAL DESCRIPTION
PC46 User’s Manual
1-2
smooth coordinated move on up to six axes using linear, parabolic or cosine velocity
profiles. It can manage as many as six independent or coordinated processes.
The PC46 will calculate the optimum velocity profile to generate the desired move, while
conforming to the acceleration and velocity data input by the host computer. This move
will consist of a smooth acceleration, followed by a constant velocity section and a smooth
deceleration to the desired distance. A graph of a typical linear velocity is shown in
Figure 1-1.
FIGURE 1-1 TYPICAL VELOCITY PROFILE
If the move parameters do not allow the motor to accelerate to the desired velocity in the
desired distance, the PC46 will automatically generate an optimum triangular velocity
profile. It can also be commanded to accelerate to a velocity and hold that velocity until
told to stop or change to a new velocity. It will then smoothly decelerate to a stop or
accelerate/decelerate to the new velocity.
Several moves of this type may be chained together to provide a more complex pattern.
The PC46 is able to store up to 124 characters in an input character buffer, plus a
separate 200 command and parameter queue for each axis, allowing several moves to be
made without host intervention. A loop counter is provided to repeat desired sections of a
complex move pattern. Loops may be nested up to four levels deep on all axes.

1. GENERAL DESCRIPTION VELOCITY PROFILES
PC46 User’s Manual 1-3
1.3. VELOCITY PROFILES
The PC46 offers three options for ramping the device to speed. The traditional constant
acceleration or linear velocity ramp (see Figure 1-1) is the default at power up or reset.
The half sinusoid acceleration or half cosine velocity ramp (see Figure 1-3) is selected by
the CN command. Since the acceleration is zero at the velocity inflection points, this
offers very smooth operation. It is used in sensitive applications such as wafer handling
on a vacuum chuck. The third option is a reverse ramp of acceleration or parabolic
velocity curve (see Figure 1-2), which can be selected by the PN command. This ramp is
commonly used to compensate for loss of motor torque at high speeds, i.e. since the
acceleration is reduced at higher speeds the required forces are reduced proportionally.
The parabola may be truncated to allow the user to select, under program control, the
reduction in acceleration (force) appropriate for the application.
LINEAR RAMPS. The OMS controls generate a linear velocity ramp in real time, i.e. while
the stage is in motion. There is no table building prior to the move and thus minimal
latency. The controls will accelerate to the specified velocity and hold that speed until just
enough move distance is left, then decelerate to a stop. If the move distance is too short
to reach speed, a triangular velocity ramp will automatically be generated. The
acceleration is a constant Amand the velocity is then:
vAt
m
=
A useful relationship is the distance required to accelerate at acceleration Amto peak
velocity Vpis:
sV
A
p
m
=
2
2
or the acceleration Amrequired to accelerate to peak velocity Vpin distances sis:
AV
s
m
p
=
2
2
PARABOLIC RAMPS. The parabolic ramp is generated in a similar fashion except the
acceleration is reduced as the stage accelerates to speed thus reducing the velocity
slope, as shown in Figure 1-2.
The acceleration follows the equation:
2
00 T
t
AAa −=
and the velocity is then:
2
2
0
02T
tA
tAv −=

VELOCITY PROFILES 1. GENERAL DESCRIPTION
PC46 User’s Manual
1-4
and the distance traveled in the ramp is:
sAt At
T
=−
0
2
0
3
2
26
where A0is the initial acceleration, tis time during the ramp and T2is total ramp time if
the acceleration had reached zero. The parameter supplied with the PN command is 10
times the ratio t
T2
which can take on values from 3 to 10, allowing the final acceleration to
range from 70% to 10% respectively of the programmed or initial value. When a move is
specified, the controls will fit the resulting velocity curve to the desired acceleration profile.
This insures that the desired acceleration is always reached at the programmed velocity,
as long as the move is long enough for the stage to reach the programmed speed. If the
move is too short to reach the programmed speed the curve is truncated, causing the
shape of the velocity curve to remain the same up to the velocity reached by the specific
move. This is consistent with the desired result of compensating for loss of motor torque.
Since the motor has not reached the programmed speed, less compensation is needed.
The parabolic ramp mode may result in reduced move time at high speeds, since a larger
acceleration may be used.
FIGURE 1-2 PARABOLIC VELOCITY PROFILE
COSINE RAMPS. The cosine ramps are generated in a similar fashion to the parabolic
ramps, except the acceleration is:
aA A
Vt
mm
p
=sin 2
Acceleration
Velocity
Time

1. GENERAL DESCRIPTION VELOCITY PROFILES
PC46 User’s Manual 1-5
and the velocity is then:
vVA
Vt
pm
p
=−








212
cos
and the distance traveled in the ramp is:
sVtV
A
At
pp
m
m
=−
24
2
2
sin Vp
where Vpis the peak velocity, Amis the peak acceleration. The distance needed to ramp
up is then:
SV
A
p
m
1
2
4
=
π
and the time required to ramp up is:
TV
A
S
A
p
mm
==
ππ
2
1
and the peak velocity is:
VAS
p
m
=41
π
FIGURE 1-3 COSINE VELOCITY PROFILE
Acceleration
Velocity
Time

VELOCITY PROFILES 1. GENERAL DESCRIPTION
PC46 User’s Manual
1-6
The cosine ramp requires
π
2times longer than a linear ramp to reach the same velocity
when using the same peak acceleration.
Since the purpose of the cosine ramp is smooth operation, it is desirable to adjust the
velocity parameters such that the desired profile is achieved even when the stage does
not reach the programmed speed as opposed to truncating the curve as the parabolic
modes do. The OMS controls look ahead to determine if the stage will be able to reach
speed in the programmed move. If not, the acceleration curve will be adjusted such that
the peak acceleration will be the programmed acceleration and the acceleration curve will
be 360 degrees of a sine wave (see Figure 1-4).
FIGURE 1-4 SHORT MOVE COSINE VELOCITY PROFILE
Acceleration
Velocity
Time

2. GETTING STARTED INTRODUCTION
PC46 User’s Manual 2-1
2.
GETTING STARTED
2.1. INTRODUCTION
The PC46 board requires one half-length slot in the PC/AT. In most cases the jumpers
on the PC46 board will not have to be changed, assuming there are no conflicts with
interrupt and I/O address lines. The factory default settings for the board have it using I/O
addresses 300 to 303 (hex) and the IRQ5 interrupt line. If these do not conflict with any
previously installed hardware in your computer, you will not need to change any jumpers
on the PC46 board.
There are seven available models of the PC46 controller board. Each model offers slightly
different functionality that corresponds to a wide pricing spectrum for the PC46 Family of
controllers. Listed below is a description of the defining characteristics for each PC46
Model.
PC46-21: This model is functionally equivalent to the PC34-2. The physical board utilizes
the latest technology, is slightly smaller and requires less power. Sixteen reconfigurable
general I/O bits are available. The update rate is 512 times per second. Constant velocity
contouring, velocity staircasing and circular interpolation are not available with this
model.1
PC46-22: This model is functionally equivalent to the PCX-2. The physical board utilizes
the latest technology, is approximately half the length and requires less power. Sixteen
reconfigurable general I/O bits are available. The update rate is 1024 times per second.
PC46-2E: This model is functionally equivalent to the PCX-2E. The physical board utilizes
the latest technology, is approximately half the length and requires less power. The board
has two additional input bits available (SYNC0 and SYNC1). The update rate is 1024
times per second.
PC46-41: This model is functionally equivalent to the PC34-4. The physical board utilizes
the latest technology, is slightly smaller and requires less power. Sixteen reconfigurable
I/O bits are available. The update rate is 512 times per second. Constant velocity
contouring, velocity staircasing and circular interpolation are not available with this
model1.
PC46-42: This model is functionally equivalent to the PCX-4. The physical board utilizes
the latest technology, is approximately half the length and requires less power. Sixteen
reconfigurable I/O bits are available. The update rate is 1024 times per second.
1Users of the PC34 should note that the PC46 has pull-up resistors on I/O bits 0-7, where the PC34 has pull-
up resistors on I/O bits 8-15.

JUMPERS 2. GETTING STARTED
PC46 User’s Manual
2-2
PC46-4E: This model is functionally equivalent to the PCX-4E. The physical board utilizes
the latest technology, is approximately half the length and requires less power. The board
has two additional input bits available (SYNC0 and SYNC1). The update rate is 1024
times per second.
PC46-6: This model is functionally equivalent to the PCX-6. The physical board utilizes
the latest technology, is approximately half the length and requires less power. The board
has two additional input bits available (SYNC0 and SYNC1). The update rate is 1024
times per second.
2.2. JUMPERS
There are five blocks of square pin jumpers that are user configurable on the PC46 board
J11, J14, J16, J44 and J86. See Figure 3-1 for the location of the jumpers.
J44, which is half-way up the board above the edge connector, determines whether the
limit inputs to an individual axis are active low or active high. With the jumper in place, the
associated axis will stop moving if the limit line, for the direction the axis is moving, is
grounded. With the jumper removed, the axis will stop if the limit line is at +5VDC. These
lines are internally pulled-up with a 2.2K ohm resistor to +5VDC, so that only a switch is
required to control the limit lines.
FIGURE 2-1 LIMIT SENSE JUMPERS FOR A FOUR AXIS BOARD
J16, just above the edge connector at the bottom of the board, determines the I/O address
range of the board. A jumper across a pair of pins sets that bit in the address low. With
the jumper removed the bit is high. The computers I/O address ranges from 200 to 3FF
(hex). The A0 and A1 address lines are decoded internally by the PC46 board and are
assumed to be 0 for base address calculations. The jumpers set the base address lines
A2 through A9. The factory default address is 300 hex. This requires jumpers across A2
and A3, making all four of the lowest bits a 0 and the least significant hex digit of the
XYZTUV
1
12
A
XIS
J44
A2 A3 A4 A5 A6 A7 A8 A9
1
16
J16
FIGURE 2-1 ADDRESS SELECT JUMPERS (default setting)

2. GETTING STARTED JUMPERS
PC46 User’s Manual 2-3
address a 0. Jumpers across A4, A5, A6 and A7 make the middle four bits 0, making the
middle hex digit of the address a 0. Removing the jumpers from A8 and A9 makes each
of these lines a 1, making the most significant hexadecimal digit a 3.
J14, just above the edge connector, determines which interrupt level the PC46 board will use
when it communicates. IRQ5 is the factory default setting.
FIGURE 2-2 INTERRUPT JUMPERS (default setting)
J11, located at the bottom left of the board, selects the configuration of I/O bits 0 through
15 as inputs or outputs. Jumpers on pins 1&8 and 2&7 of J11 select I/O bits 0-7 as
outputs. No jumpers on pins 3&6 and 4&5 select I/O bits 8 through 15 as inputs. Figure
2-3 shows the default settings for the PC46-21 model. (NOTE: The factory default jumper
setting for J11 varies depending on the model of PC46.)
FIGURE 2-3 I/O CONFIGURATION JUMPERS (default setting)
J86, is used for biasing unused encoder inputs. When a single ended encoder is used,
the unused inputs can be biased using wire-wrap wire or jumpers. J86 is for the X and Y
feed back axes. See Figure 3-1 for jumper locations.
NOTE: Jumpers J20, J21, J62, J80 and J96 are intended for factory use ONLY and are not to be
reconfigured by the user.
IRQ15 IRQ14 IRQ12 IRQ11 IRQ10 IRQ7 IRQ6 IRQ5
1
22
J14
IRQ4 IRQ3 IRQ2
12-13 8-11
4-7
0-3
1
8
J11
I/O BIT

HARDWARE INSTALLATION 2. GETTING STARTED
PC46 User’s Manual
2-4
2.3. HARDWARE INSTALLATION
1. Follow the instructions included in your controller’s support software. (Usually
these can be found in a file called README.TXT)
2. Turn off power to your computer and disconnect its power cord.
3. Remove the computers cover.
4. Choose an empty expansion slot in the motherboard and remove its
associated metal cover from the back of the computer. Be sure to save the
screw.
5. Check the PC46 boards jumpers for proper configuration. Note: It is a good
practice to operate the PC46 at the default jumper settings for the first time
and for trouble-shooting your system, then proceed with the customizing the
jumpers to your specific application.
6. Slide the PC46 board down into the edge connector, insuring the board is lined
up correctly in the card guides and in the connector.
7. Double check the board to insure it is properly seated in the connector.
8. Use the screw removed from the cover to attach the metal bracket of the PC46
board to the chassis of the computer.
9. Replace the cover of the computer.
10. Replace the power cord and turn the computer on. (Do not connect the PC46
to other parts of system until communication is established with the host for
ease in trouble-shooting.)
11. Allow the computer to boot up.
12. Install the OMS Support Software disk in the PC after boot up is complete.
Type: PC4XCOMM at the command prompt with the drive letter corresponding
to the location of the support software disk. This will load the program that will
allow the user to enter PC46 control commands at the keyboard or download a
file of commands. The responses from the PC46 board will be displayed on
the computer’s screen.
13. Press <Enter> when the program asks for a file name.
14. The program will state that you are in the interactive mode. Enter the PC46
commands EN WY on the keyboard. EN turns echoing on which causes the
typed commands to be echoed from the controller to the display. WY asks the
PC46 board “who are you”. The board responds with its model type and
firmware version number (i.e. PC46 ver 3.00-41 ).
15. If a message similar to this is displayed, the board was correctly installed and
you are communicating with the PC46.
16. If no message was displayed, double check the boards installation. If you are
still having a problem contact Oregon Micro Systems for assistance.

2. GETTING STARTED SOFTWARE INSTALLATION
PC46 User’s Manual 2-5
2.4. SOFTWARE INSTALLATION
The Support Software disk contains several versions of a program which allow the user to
interact with an Oregon Micro Systems PC46 motion control board. The user may type
PC46 commands on the computer’s keyboard and they are passed to the PC46 board.
The PC46 board’s responses are displayed on the computer’s screen. The user may,
when prompted, optionally give the program the name of an ASCII text file that contains
PC46 commands. The program will send the contents of the file to the PC46 board.
Example code is included on the disk, allowing PC46 users to use the routines in
application programs using OMS motion controls. No license is required.
See section 7. HOST SOFTWARE of this manual for more information on the software
provided by OMS.
2.5. MOTOR CONTROL CONNECTOR
The motor control connector (J69) on the PC46 board consists of two rows of square pins,
each row has 25 pins for a total of 50 pins. Depending on the PC46 model type, up to
sixteen of the pins are general purpose I/O lines which can be used for any function the
user wishes to define. They can also be used to synchronize motor movement with
external events or vice versa.
Each axis uses a set of eight pins on the motor control connector. Each set is used to
control an individual axis.
The 8 pins of an axis set are: Step Output, +5VDC Output, Auxiliary Output, Direction
Output, Negative Limit Switch Input, Ground, Home Switch Input and Positive Limit Switch
Input. See Section 4. DRIVER INTERFACE for a detailed description of the connector.
Boards with the Encoder Option use two sets of 8 pins as encoder input for the X and Y
axes. The 8 pins of an encoder pin set are: Index +, +5VDC, Phase A -, Phase A +,
Index -, Ground, Phase B - and Phase B +. See Section 5. ENCODER OPTION for a
detailed description of the connector.

MOTOR CONTROL CONNECTOR 2. GETTING STARTED
PC46 User’s Manual
2-6
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3. I/O CHANNEL INTERFACE I/O CHANNEL
PC46 User’s Manual 3-1
3.
I/O CHANNEL INTERFACE
3.1. I/O CHANNEL
The PC system bus has available several slots for interfacing I/O cards such as the PC46.
The AT has an additional connector to make available the 16 bit data bus and additional
address lines. Since the PC46 is an 8 bit I/O device, it uses only the low order 8 bits of
the data bus and the first 10 address lines in this family of computers. It can thus be used
in any computer which meets the IBM I/O channel specification. It may not fit physically in
some XT computers due to conflict of the AT style connector with parts on the mother-
board. The PC46 is half the size of a full-length board. Table 3-1 and Table 3-2 show the
I/O channel signals which are also the descriptions of the pins on the edge connector of
the PC46 board. The front, or component side of the board, is the A side of the connector
on the PC46 while the back, or solder side, is the B side.
3.1.1. PC/AT DATA BUS
The data bus is an 8 bit, bi-directional, 3-state bus. Direction of data is controlled by
the PC/AT host computer. The data bus uses high-level active logic. All data and
commands are passed through this data bus.
3.1.2. PC/AT ADDRESS BUS
The address bus is a 20 bit high-level active bus. This bus is always driven by the
PC/AT host computer. The address bus provides the 20 address lines for decoding
by either memory or I/O. MEMW, MEMR, IOW and IOR control lines distinguish
between memory and I/O transfers and determine the direction of transfer. Since the
PC46 is an I/O device it uses only A0 through A9 and only IOW and IOR to
determine the direction of transfer.
3.1.3. MEMORY AND I/O CONTROL
These lines provide the signals for fundamental memory and I/O operations.
3.1.4. INTERRUPT REQUEST
The PC/AT supports interrupts to the system bus at levels 2 (IRQ2) through 7
(IRQ7), 10 through 12, 14 and 15. These are active high input only signals to the
system bus. They go directly to the system interrupt controller which generates the
vector during an interrupt acknowledge cycle. The PC46 supports all 11 interrupt
levels which can be selected by a jumper at J14. Refer to Section 3.3 for details of
configuration.

I/O CHANNEL 3. I/O CHANNEL INTERFACE
PC46 User’s Manual
3-2
TABLE 3-1 CONTROL LINE DESCRIPTION
SIGNAL DESCRIPTION
MEMW*
This is a low level active signal used to write data from
the system bus into memory and is thus not used by the
PC46
MEMR*
This is a low level active signal used to read data from
memory to the system bus and is thus not used by the
PC46
IOW*
This is a low level active signal used to write data into
I/O. It is driven by the system bus and indicates the
address bus contains a valid I/O address. It is used by
the PC46 as an address qualifier for write operations.
IOR*
This is a low level active signal used to read data from
an I/O device onto the system bus. It is driven by the
system bus and indicates the address bus contains a
valid I/O address. It is used by the PC46 as an address
qualifier for read operations.
ALE
This output only signal driven by the system bus is
decoded by the PC46 to indicate a valid address on the
system bus.
3.1.5. CLOCK AND OSC LINES
These are provided on the system bus. The PC46 has its own on board clock and
does not use either of these signals.
3.1.6. RESET DRV
This line is a reset driver which is provided on the bus. The PC46 has an on board
reset timer and uses the RESET DRV signal to initiate this timer at power up or
during a system reset. This bus signal is not active during a warm boot such as the
CTL-ALT-DEL or CTL-BREAK and thus the PC46 is not reset under these
conditions. It can, however, be reset on computers equipped with a reset push
button.
3.1.7. I/O CH RDY
This line is used in conjunction with memory wait state generation. It is used by the
PC46 since wait states are not required.
3.1.8. I/O CH CK
This signal is used in conjunction with data parity checking. It is used since parity is
not checked by the PC46.