SeaLevel COMM+4.PCI User manual

Part # 7401
Sealevel Systems, Inc
155 Technology Place
P.O. Box 830
Liberty, SC 29657 USA
Phone: [phone]
FAX: [phone]
www.sealevel.com
VERSA COMM+4.PCI
USER MANUAL
TM

Contents
INTRODUCTION ........................................................................ 1
OVERVIEW ...........................................................................................1
WHAT’S INCLUDED..............................................................................1
CARD SETUP............................................................................. 2
CLOCK MODES.....................................................................................2
BAUD RATES AND DIVISORS FOR THE ‘DIV1’ MODE............................3
BAUD RATES AND DIVISORS FOR THE ‘DIV2’ MODE............................4
ADDRESS AND IRQ SELECTION.............................................................4
INSTALLATION.......................................................................... 5
OPERATING SYSTEM INSTALLATION ....................................................5
For Windows Users.......................................................................5
Other Operating Systems ..............................................................5
SYSTEM INSTALLATION .......................................................................5
TECHNICAL DESCRIPTION ....................................................... 6
INTERRUPTS.........................................................................................6
WHY USE AN ISP?...............................................................................7
CONNECTOR PIN ASSIGNMENTS...........................................................7
DB-25 (RS-232 DTE) (DB-25 MALE)....................................7
DB-9 (EIA-574 DTE) (DB-9 MALE)......................................8
DB-37 (DB-37 MALE).............................................................8
SPECIFICATIONS....................................................................... 9
ENVIRONMENTAL SPECIFICATIONS.......................................................9
POWER CONSUMPTION........................................................................9
MEAN TIME BETWEEN FAILURES (MTBF)..........................................9
PHYSICAL DIMENSIONS........................................................................9
APPENDIX A -TROUBLESHOOTING....................................... 10
PCI COM NUMBER SELECTION IN WINDOWS 95/98.........11
APPENDIX B -HOW TO GET ASSISTANCE............................. 12
APPENDIX C -ELECTRICAL INTERFACE................................ 13
RS-232.............................................................................................13
APPENDIX D -ASYNCHRONOUS COMMUNICATIONS ............ 14
APPENDIX E -SILK-SCREEN.................................................. 15
APPENDIX F -COMPLIANCE NOTICES ................................... 16

FEDERAL COMMUNICATIONS COMMISSION STATEMENT...................16
EMC DIRECTIVE STATEMENT ...........................................................16
WARRANTY............................................................................ 17
Figures
Figure 1 -Clocking Mode ‘Divide By 4’.........................................................2
Figure 2 -Clocking Mode ‘Divide By 2’.........................................................2
Figure 3 -Clocking Mode ‘Divide By 1’.........................................................2
Figure 4 -Asynchronous Communications Bit Diagram...............................14
© 1999a Sealevel Systems, Incorporated. All rights reserved.

Introduction
Sealevel Systems VERSA COMM+4.PCI Page 1
Introduction
Overview
The Sealevel Systems VERSA COMM+4.PCI provides the PC with four
RS-232 asynchronous ports. The VERSA COMM+4.PCI allows for connection
to any device utilizing the RS-232 electrical interface, such as modems,
data-entry terminals, and plotters.
What’s Included
The VERSA COMM+4.PCI is shipped with the following items. If any of these
items are missing or damaged, contact the supplier.
•VERSA COMM+4.PCI Serial I/O Adapter
•DB-37 to four DB-25 ‘Spider Cable’ (DB-9 Spider Cable is
available)
•Serial Utility Software
•User Manual

Card Setup
Sealevel Systems VERSA COMM+4.PCI Page 2
Card Setup
Clock Modes
The VERSA COMM+4.PCI employs a unique clocking option that allows the
end user to select from divide by 4, divide by 2 and divide by 1 clocking modes.
This mode is selected at J5.
To select the Baud rates commonly associated with COM: ports (i.e. 2400,
4800, 9600, 19.2, … 115.2K Bps) place the jumper in the divide by 4 mode
(silk-screen DIV4).
DIV1
DIV2
DIV4
Figure 1-Clocking Mode ‘Divide By 4’
To double these rates up to a maximum rate for 230.4K bps place the jumper in
the divide by 2 (silk-screen DIV2) position.
DIV1
DIV2
DIV4
Figure 2-Clocking Mode ‘Divide By 2’
To select the maximum data rate (460.8K bps) place the jumper in the divide by
1 (silk-screen DIV1) position.
DIV1
DIV2
DIV4
Figure 3-Clocking Mode ‘Divide By 1’

Card Setup
Sealevel Systems VERSA COMM+4.PCI Page 3
Baud Rates and Divisors for the ‘Div1’ mode
The following table shows some common data rates and the rates you should
choose to match them if using the adapter in the ‘Div1’ mode.
For this Data Rate Choose this Data Rate
1200 bps 300 bps
2400 bps 600 bps
4800 bps 1200 bps
9600 bps 2400 bps
19.2K bps 4800 bps
57.6 K bps 9600 bps
115.2 K bps 19.2K bps
230.4K bps 57.6 K bps
460.8K bps 115.2 K bps
If your communications package allows the use of Baud rate divisors, choose
the appropriate divisor from the following table:
For this Data Rate Choose this Divisor
1200 bps 384
2400 bps 192
4800 bps 96
9600 bps 48
19.2K bps 24
38.4K bps 12
57.6K bps 8
115.2K bps 4
230.4K bps 2
460.8K bps 1

Card Setup
Sealevel Systems VERSA COMM+4.PCI Page 4
Baud Rates and Divisors for the ‘Div2’ mode
The following table shows some common data rates and the rates you should
choose to match them if using the adapter in the ‘Div2’ mode.
For this Data Rate Choose this Data Rate
1200 bps 600 bps
2400 bps 1200 bps
4800 bps 2400bps
9600 bps 4800 bps
19.2K bps 9600 bps
38.4K bps 19.2K bps
57.6 K bps 38.4K bps
115.2 K bps 57.6 K bps
230.4 K bps 115.2 K bps
If your communications package allows the use of Baud rate divisors, choose
the appropriate divisor from the following table:
For this Data Rate Choose this Divisor
1200 bps 192
2400 bps 96
4800 bps 48
9600 bps 24
19.2K bps 12
38.4K bps 8
57.6K bps 4
115.2K bps 2
230.4K bps 1
Address and IRQ selection
The VERSA COMM+4.PCI is automatically assigned I/O addresses and IRQs
by your motherboard BIOS. Only the I/O address may be modified by the user.
Adding or removing other hardware may change the assignment of I/O
addresses and IRQs.

Installation
Sealevel Systems VERSA COMM+4.PCI Page 5
Installation
Operating System Installation
For Windows Users
Start by choosing Install Software at the beginning of the CD. Choose
Asynchronous COM: Port Software, SeaCOM.
Other Operating Systems
Refer to the appropriate section of the Serial Utilities Software.
System Installation
The VERSA COMM+4.PCI can be installed in any of the PCI expansion slots
and contains a single jumper strap that must be set for proper operation. Please
see the Card Setup section of the manual for information on this jumper.
1. When running Windows 9x/NT install software before installing adapter.
2. Turn off PC power. Disconnect the power cord.
3. Remove the PC case cover.
4. Locate an available PCI slot and remove the blank metal slot cover.
5. Gently insert the VERSA COMM+4.PCI into the slot. Make sure that the
adapter is seated properly.
6. Replace the screw.
7. Replace the cover.
8. Connect the power cord.
Installation is complete.

Technical Description
Sealevel Systems VERSA COMM+4.PCI Page 6
Technical Description
The VERSA COMM+4.PCI utilizes the 16C554 UART. This chip features
programmable baud rate, data format, interrupt control and a 16-byte input and
output FIFO, and is functionally 4 16C550 UARTs. The 16C654 UART is also
available on this card, which has a 64-byte FIFO as opposed to the 16-byte
FIFO available in the 16C554.
Interrupts
A good description of an interrupt and its importance to the IBM PC can be
found in the book ‘Peter Norton’s Inside the PC, Premier Edition’:
“ One of the key things that makes a computer different from any other kind of
man-made machine is that computers have the capability to respond to the
unpredictable variety of work that comes to them. The key to this capability is a
feature known as interrupts. The interrupt feature enables the computer to
suspend whatever it is doing and switch to something else in response to an
interruption, such as the press of a key on the keyboard.”
A good analogy of a PC interrupt would be the phone ringing. The phone ‘bell’
is a request for us to stop what we are currently doing and take up another task
(speak to the person on the other end of the line). This is the same process the
PC uses to alert the CPU that a task must be preformed. The CPU upon
receiving an interrupt makes a record of what the processor was doing at the
time and stores this information on the ‘stack’; this allows the processor to
resume its predefined duties after the interrupt is handled, exactly where it left
off. Every main sub-system in the PC has it’s own interrupt, frequently called
an IRQ (short for Interrupt ReQuest). The following IRQ table will define the
system IRQs as well as show typically free IRQs.
In these early days of PCs Sealevel Systems decided that the ability to share
IRQs was an important feature for any add-in I/O card. Consider that in the IBM
XT the available IRQs were IRQ0 through IRQ7. Of these interrupts only IRQ2-
5 and IRQ7 were actually available for use. This made the IRQ a very valuable
system resource. To make the maximum use of these system resources
Sealevel Systems devised an IRQ sharing circuit that allowed more than one
port to use a selected IRQ. This worked fine as a hardware solution but
presented the software designer with a challenge to identify the source of the
interrupt. The software designer frequently used a technique referred to as
‘round robin polling’. This method required the interrupt service routine to
‘poll’ or interrogate each UART as to its interrupt pending status. This method
of polling was sufficient for use with slower speed communications, but as
modems increased their through put abilities this method of servicing shared
IRQs became inefficient.