Quatech Asynchronous Communications Adapter... User manual

DSC-200/300
Two Channel RS-422/485 Asynchronous
Communications Adapter
for PCI bus
User's Manual
QUATECH, INC. TEL: [phone]
5675 Hudson Industrial Parkway FAX: [phone]
Hudson, Ohio 44236 http://www.quatech.com

WARRANTY INFORMATION
Quatech, Inc. warrants the DSC-200/300 to be free of defects for five(5) years
from the date of purchase. Quatech, Inc. will repair or replace any board that fails to perform
under normal operating conditions and in accordance with the procedures outlined in this
document during the warranty period. Any damage that results from improper installation,
operation, or general misuse voids all warranty rights.
Please complete the following information and retain for your records. Have this
information available when requesting warranty service.
DATE OF PURCHASE:
MODEL NUMBER: DSC-200/300
PRODUCT DESCRIPTION: Two Channel RS-422/485 Asynchronous
PCI Bus Communications Adapter
SERIAL NUMBER:

(c) 1998 - 2000, Quatech, Inc.
NOTICE
The information contained in this document cannot be reproduced in any form
without the written consent of Quatech, Inc. Likewise, any software programs that might
accompany this document can be used only in accordance with any license agreement(s)
between the purchaser and Quatech, Inc. Quatech, Inc. reserves the right to change this
documentation or the product to which it refers at any time and without notice.
The authors have taken due care in the preparation of this document and every
attempt has been made to ensure its accuracy and completeness. In no event will Quatech,
Inc. be liable for damages of any kind, incidental or consequential, in regard to or arising out of
the performance or form of the materials presented in this document or any software
programs that might accompany this document.
Quatech, Inc. encourages feedback about this document. Please send any written
comments to the Technical Support department at the address listed on the cover page of this
document.
DOS, Windows ME, Windows 2000, Windows 98, Windows 95, Windows NT are trademarks
or registered trademarks of Microsoft Corporation. OS/2 is a registered trademark of IBM
Corporation. All other trademarks or registered trademarks are property of their respective
owners.

Declaration of Conformity
Manufacturer's Name: Quatech Inc.
Manufacturer's Address: 55675 Hudson Industrial Parkway
Hudson, Ohio 44236 (USA)
Application of Council Directive: 89/336/EEC
Standards to which
Conformity is Declared: * EN50081-1 (EN55022,
EN60555-2, EN60555-3)
* EN50082-1 (IEC 801-2,
IEC 801-3, & IEC 801-4)
Type of Equipment: Information Technology
Equipment
Equipment Class: Commercial, Residential, & Light
Industrial
Product Name: PCI Dual Serial Communications
Card
Model Number : DSC-200/300 (750,IND)

328.5 Half-Duplex/Full-Duplex Selection ......................... 318.4 AUXIN/AUXOUT Loopback ................................ 318.3 XCLK .......................................................... 308.2 RCLK .......................................................... 308.1 RTS/cts Handshake .......................................... 29
8 External Connections .....................................
28
7 OS/2 ............................................................
256.1.1 QTPCI.EXE ................................................. 25
6 DOS and Other Operating Systems ..................
245.6 Windows NT ................................................. 235.5 Using the "New Hardware Found" Wizard ................ 215.4 Windows 95 .................................................. 205.3 Windows 98 ................................................... 195.2 Windows 2000 ................................................ 185.1 Windows Millennium ........................................ 18
5 Windows Configuration .................................
174.4.2 Clock Rate Multiplier ..................................... 164.4.1 Enhanced Serial Adapter Identification ................. 164.4 Options Register .............................................. 154.3 Interrupt Status Register ..................................... 154.2 Enabling the Special Registers .............................. 144.1 Base Address and Interrupt Level (IRQ) ................... 14
4 Address Map and Special Registers .................
13
3 Hardware Installation ....................................
12
2.4.2 Force High-Speed UART Clock (X2, X4, or X8,
J10-J12) ...........................................................
112.4.1 Enable Scratchpad Register (SPAD, J13) ................. 112.4 Clock Rate and Optional Registers .......................... 102.3 Full-duplex/Half-duplex Operation ........................ 102.2 Signal Connections ........................................... 92.1 RS-422 or RS-485 Signal Line Termination .................. 9
2 Hardware Configuration .................................
81.1.1 "IND" Option --- Surge Suppression Upgrade ........... 81.1 Features ........................................................ 7
1 General Information ........................................

38
11 Troubleshooting .........................................
37
10 Specifications ..............................................
36
9 PCI Resource Map ..........................................
358.7 RS-422/485 Peripheral Connection .......................... 348.6 Termination Resistors ........................................

1General Information
The Quatech, Inc. DSC-200/300 provides two RS-422 or RS-485 asynchronous
serial communication interfaces for IBM-compatible personal computer systems using
the PCI expansion bus. The DSC-200/300 uses Quatech's new Enhanced Serial Adapter
design. Legacy serial port data rates are limited to a maximum of 115,200 bits per
second. Quatech Enhanced Serial Adapters can achieve data rates as high as 921,600
bits per second.
As a PCI device, the DSC-200/300 requires no hardware configuration. The card
is automatically configured by the computer's BIOS or operating system. The two
serial ports share a single interrupt line and are addressed in a contiguous block of 16
bytes. Aspecial interrupt status register is provided to help software to manage the
shared interrupt.
The DSC-200/300's serial ports are using 16750 Universal Asynchronous
Receiver/Transmitters (UARTs). These UARTs contain hardware buffers (FIFOs) which
reduce processing overhead and allow higher data rates to be achieved. The 16750
contains a 64-byte FIFO and can transmit and receive data at a rate of up to 921,600 bits
per second. The 16750 is recommended for heavy multitasking environments and for
applications involving high data rates.
The DSC-200/300 is supported under several popular operating systems and
environments. Contact the sales department for details on current software offerings.
Most device drivers are available for download from the Quatech world wide web site
at http://www.quatech.com.
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1.1Features
The standard DSC-200/300 implements each of its communication channels with
a 16750 UART and uses standard line driver and receiver components. For improved
performance and industrial-grade reliability.
1.1.1"IND"Option --- Surge Suppression Upgrade
The "IND"upgrade provides the protection essential for reliable use in an
industrial environment. Each communication line has a surge suppressor capable of
sustaining up to 40A20us peak transient surges, a clamping voltage of 30V and a peak
energy dissipation of 0.1 Joules.
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2Hardware Configuration
The DSC-200/300 is automatically configured at boot time by the computer's
BIOS or operating system. There are no required switches or jumpers to set for
installation.
This chapter lists a number of jumper settings that control various hardware
features. Jumpers J1-J4, located in a column near the D-9 connectors, control the RS-422
or RS-485 signal line termination. Jumpers J5-J8, located in a column just to the right of
J1-J4, control how signals are routed from the UARTs to the connector, as well as full- or
half- duplex operation. Jumpers J10-J13, grouped together at the end of the board
opposite the D-9connectors, control special options.
Any changes from the factory default should be made before installing the
DSC-200/300 in the computer.
2.1RS-422 or RS-485 Signal Line Termination
Jumpers J1-J4 allow the selection of 100-ohm RS-422 termination, 120-ohm RS-485
termination, or no termination at all. The factory default, shown in Figure 1, is RS-422
termination. For full details, see page 24.
1
2
3
RS-422 termination
(100 ohms)
(factory default)
Jumpers J1-J4
Figure 1--- Factory default signal termination settings
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2.2Signal Connections
The DSC-200/300 provides each of two serial ports with four differential signal
pairs: TxD, RxD, AUXOUT, and AUXIN. TxD and RxD are always present at the
connector. The AUXOUT and AUXIN signals can be used to support RTS/CTS
handshaking, external clocking, or external signal loopback. The factory default
configuration, as shown in Figure 2, is a loopback of AUXOUT to AUXIN at the
connector, with RTS and CTS looped back on the board. There is an extensive
discussion of this topic starting on page 19.
2.3Full-duplex/Half-duplex Operation
The DTR or RTS modem control output of the UART can be used to enable and
disable the transmit drivers. The inverse of these signals can also be used to enable
and disable the receivers. These options are selectable per channel. The factory
default, as shown in Figure 2, is for both the drivers and receivers of both channels to
be continuously enabled. Two spare jumpers are installed in neutral positions. For
details, refer to page 22.
The DSC-200/300 is shipped from the factory with each channel configured as
shown in Figure 2.
Loopback RTS to CTS
Loopback AUXOUT to AUXIN
Loopback XCLK to RCLK
CTS
AUXIN
XCLK
RTS
AUXOUT
RCLK
1
2
36
5
4
Full Duplex Operation
1
2
3
6
5
4
RTS
DTR
Tx ENABLE
Tx ENABLE
Tx ENABLE Rx ENABLE
(spare jumpers supplied)
JumpersJ5,J7
JumpersJ6,J8
Figure 2--- Factory default signal interface settings
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2.4Clock Rate and Optional Registers
Figure 3 shows the jumper configuration as shipped from the factory, with two
spare jumpers applied in neutral positions. Remove one or both and apply as shown
in following subsections to set optional features.
SPAD
X2
X4
X8
J10
J11
J12
J13
Figure 3--- Factory default clock rate and options settings
2.4.1Enable Scratchpad Register (SPAD, J13)
In the default configuration, an Interrupt Status Register and an Options Register
(see page 10) replace the scratchpad (base address + 7) of each UART. If the SPAD
jumper is applied as in Figure 4, the UART scratchpad registers are enabled, and the
Interrupt Status Register and the Options Register are not available.
SPAD
X2
X4
X8
J10
J11
J12
J13
Figure 4--- Enable scratchpad registers
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2.4.2Force High-Speed UART Clock (X2, X4, or X8, J10-J12)
These jumpers force an increase of the UART input clock frequency by a factor of
two, four, or eight. This feature can allow legacy software to use baud rates above
115,200 bits per second. It is also useful if the serial port device driver does not directly
support setting the higher baud rates through the Options Register (see page 10).
If one of these jumpers is applied, it overrides any value written to the Options
Register to set the clock multiplier by software. The effective baud rate will be either
two, four, or eight times the value for which the UART itself is programmed.
The factory default is none of these jumpers applied, which allows for software
control of the clock multiplier via the Options Register. The Options Register powerup
default is for a standard times-1 clock of 1.8432 MHz for compatibility with standard
serial ports.
SPAD
X2
X4
X8
J10
J11
J12
J13
Force times-eight clock
Baud rates up to 921.6 kbps
SPAD
X2
X4
X8
J10
J11
J12
J13
Force times-two clock
Baud rates up to 230.4 kbps
SPAD
X2
X4
X8
J10
J11
J12
J13
Factory default
software control
SPAD
X2
X4
X8
J10
J11
J12
J13
Force times-four clock
Baud rates up to 460.8 kbps
Figure 5--- Clock multiplier jumper options
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3Hardware Installation
1. Turn off the power of the computer system in which the DSC-200/300 is to be
installed.
2. Remove the system cover according to the instructions provided by the
computer manufacturer.
3. Make any desired optional jumper setting changes.
4. Install the DSC-200/300 in any empty PCI expansion slot. The board should be
secured by installing the Option Retaining Bracket (ORB) screw.
5. Replace the system cover according to the instructions provided by the
computer manufacturer.
6. Attach and secure the cable connectors to the desired equipment.
7. Turn on the power of the computer system.
The output of the DSC-200/300 is two female 9-pin D-connectors.
J10
J11
J12
J13
X2
X4
X8
SPAD
Clock multiplier/
scratchpad select
Termination select
Interface configuration
J1
J2
J3
J4
J5
J6
J7
J8
port 1
port 2
Serial
Port
2
Serial
Port
1
Figure 6--- Jumper/connector locations
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4Address Map and Special Registers
This chapter explains how the two UARTs and special registers are addressed,
as well as the layout of those registers. This material will be of interest to programmers
writing driver software for the DSC-200/300.
4.1Base Address and Interrupt Level (IRQ)
The base address and IRQ used by the DSC-200/300 are determined by the BIOS
or operating system. Each serial port uses 8 consecutive I/O locations. The two ports
reside in a single block of I/O space in eight byte increments, for a total of 16
contiguous bytes, as shown in Figure 7.
Base Address + 8
to
Base Address + 15
Port
2
Base Address + 0 to Base Address + 7Port 1
I/O Address Range
Channel
Figure 7--- Port Address Map
All two serial ports share the same IRQ. The DSC-200/300 signals a hardware
interrupt when any port requires service. The interrupt signal is maintained until no
port requires service. Interrupts are level-sensitive on the PCI bus.
The base address and IRQ are automatically detected by the device drivers
Quatech supplies for various operating systems. For cases where no device driver is
available, such as for operation under DOS, Quatech supplies the "QTPCI" DOS
software utility for manually determining the resources used. See page 17 for details.
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4.2Enabling the Special Registers
The DSC-200/300 contains two unique registers, an Interrupt Status Register and
an Options Register. These registers are enabled when the SPAD jumper (J13) is
removed (factory default). They replace the UART Scratchpad Register on accesses to
register address 7.
The Interrupt Status Register and Options Register are accessed through the
scratchpad location of any UART. The DLAB bit of the UART (Line Control Register,
bit 7) is used to select between the two registers. The most recent write of a DLAB bit in
any UART selects between the two registers as shown in Figure 8.
Scratchpad RegistersappliedX
Options Register
removed
1
Interrupt Status Register
removed
0
Register selected for
address 7 accesses
SPAD JumperDLAB Bit
Figure 8--- DLAB bit selects between special registers
4.3Interrupt Status Register
The read-only Interrupt Status Register can be used to quickly identify which
serial ports require servicing after an interrupt. Reading the Interrupt Status Register
will return the interrupt status of the entire DSC-200/300, as shown in Figure 9. The
individual bits are cleared as the interrupting ports are serviced. The interrupt service
routine should ensure that the interrupt status register reads zero before exiting.
Port 1 --- 1 if interrupt pending
0
Port 2 --- 1 if interrupt pending
1
0 (not used)2
0 (not used)3
0 (not used)
4
0 (not used)
5
0 (not used)6
0 (not used)7 (MSB)
Description
Bit
Figure 9--- Interrupt Status Register
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4.4Options Register
The Options Register allows software to identify the DSC-200/300 as a Quatech
Enhanced Serial Adapter. It also allows software to set the UART clock rate multiplier.
Figure 10 shows the structure of the Options Register.
The powerup default of the Options Register is all bits zero.
Clock rate multiplier bit 0RR00
Clock rate multiplier bit 1
RR1
1
(reserved, 0)-2
(reserved, 0)-3
(reserved, 0)
-
4
(reserved, 0)-5
ID bit 0
ID0
6
ID bit 1ID17 (MSB)
Description
Name
Bit
Figure 10--- Options Register bit definitions
4.4.1Enhanced Serial Adapter Identification
The ID bits are used to identify the DSC-200/300 as a Quatech Enhanced Serial
Adapter. Logic operations are performed such that the values read back from these bits
will not necessarily be the values that were written to them. Bit ID1 will return the
logical-AND of the values written to ID[1:0], while bit ID0 will return their
exclusive-OR.
Software can thus identify a Quatech Enhanced Serial Adapter by writing the ID
bits with the patterns shown in the "write" column of Figure 11, then reading the bits
and comparing the result with the patterns in the "read" column. Matching read
patterns verify the presence of the Options Register.
0111 1001
1
0
1
0
0000 ID0ID1ID0ID1
R
ead
W
rite
Figure 11 --- ID bit write/read table
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4.4.2Clock Rate Multiplier
A standard serial port operates at a clock speed of 1.8432 MHz. In order to
achieve higher data rates, Quatech Enhanced Serial Adapters can operate at two times,
four times, or even eight times this standard clock speed. This is controlled by the
clock rate multiplier bits in the Options Register.
Software can determine the UART clock frequency by reading the clock rate
multiplier bits RR1 and RR0 in the Options Register as shown in Figure 12. RR1 and
RR0 can be set by writing to the Options Register if the X2, X4, and X8 jumpers (J10-J12)
are all removed. If one of these jumpers is applied, the RR1 and RR0 bits are forced to
the appropriate value. Reading the Options Register will always return the clock rate
multiplier at which the board is operating.
* 16750 UART only
921.6 kbaud *14.7456 MHzX811
460.8 kbaud *
7.3728 MHz
X4
0
1
230.4 kbaud3.6864 MHzX210
115.2 kbaud1.8432 MHz
X1
(default)
00
M
aximum Data
Rate
UART Clock
Frequency
Clock Rate
Multiplier
RR0RR1
Figure 12 --- Rate Register bit definition
At powerup and reset, the Options Register is initialized to 0. The DSC-200/300
will thus powerup in the x1 mode with software control of the clock rate multiplier
enabled as long as the X2, X4, and X8 jumpers are not installed.
Software can control high baud rates through a combination of changing the
clock rate multiplier and the UART baud rate divisor. For example, a baud rate of
230.4 kbps could be achieved by setting the clock rate multiplier to X2 mode (or by
applying the X2 jumper) and setting a software application for 115.2 kbps.
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5Windows Configuration
5.1Windows Millennium
1. After inserting the DSC 200/300 for the first time the "Add New Hardware
Wizard" will begin. Select "Search for the best driver for your device.". Check the
"Removable media" and "Specify location" box. Click the "Next" button.
3. Window will locate the proper INF file and copy the file from the CD. Click
the "Next" button.
4. The final dialog screen will verify the file copy from the CD. Click the
"Finish" button.
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5.2Windows 2000
1. After inserting a DSC-200/300 for the first time, the "Add New Hardware
Wizard will appear at start up. Click the "OK" button.
2. The following dialog box insert the Quatech COM CD (shipped with the device).
Click the "OK" button.
4. The following dialog box will display the appropriate INF file on the CD in
drive. Click the "OK" button.
5. Window will copy the INF file from the CD and display a final dialog
indication that the process is complete. Click the "Finish" button.
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5.3Windows 98
1. After inserting a DSC-200/300 for the first time, the "Add New Hardware
Wizard will appear at start up. Click the "Next" button.
2. Select "Search for the best driver for you device". Click the "Next" button.
3. On the next dialog, select the "CD-ROM DRIVE" check box. Insert the Quatech
COM CD (shipped with the device) into the CD-ROM drive.
Click the "Next" button.
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