Adapter ID

5FD8

Name

QUATECH ES-2000 Eight Asynchronous RS-422
QUATECH ES-3000 Eight Asynchronous RS-485

Class

COM SER  Serial Port

Origin

QUAT  Quatech Inc.

Technical information contained in this page are edited excerpts from the QUATECH Reference Manual (es-2000.pdf), Copyright © Quatech Inc.

Specifications

Bus interface	MicroChannel 16-bit
Controller	NS-16552
Interface	High-density D-62 female connector *
Transmit drivers	ES-2000 MC3487 / ES-3000 75174
Receive buffers	ES-2000 MC3486 / ES-3000 75175
I/O address range	0000H - FFFFH
Interrupt levels	IRQ 3-7, 9, 10
Power requirements	1128mA typical, 1264mA maximum at +5V

* Connector pinout is described in the ES-2000 Reference Manual.

Description

The Quatech ES - 2000 provides eight independent asynchronous RS-422 serial communication channels for systems utilizing the MicroChannel architecture. The ES-3000 is an RS-485 version of the adapter. The eight ports of the ES-2000/ES-3000 occupy a contiguous 64 byte block of I/O address space. The base address of this block may be located anywhere within the available I/O address range of the system.

The ES-2000/ES-3000 serial interfaces are realized through four 16552 DUARTs (Dual Universal Asynchronous Receiver/Transmitters). The 16552 is a two channel version of the 16550 used in the IBM PS/2 family of personal computers and is compatible with the 8250 and 16450 UARTs used in the PC/XT/AT models. In addition, the 16550 and 16552 support transmit and receive FIFOs to reduce CPU overhead at higher data rates.

Address and interrupt selections are accessed through the Programmable Option Select using the IBM installation utilities. In addition, jumpers are provided to select input clock frequency and to control the information exchanged on the auxiliary channels.

16552 Features

The 16552 is a two channel version of the 16550 Universal Asynchronous Receiver/Transmitter (UART). The two channels are completely independent except for the common clock oscillator input. Each channel of the 16552 enters character mode after reset and in this mode appears as a 16450 to application software. An additional FIFO mode can be selected to reduce CPU overhead at high data rates. The FIFO mode increases performance by providing two internal 16-byte FIFOs (one transmit and one receive) to buffer data and reduce the number of interrupts issued to the CPU.

Auxiliary Channel Configuration

Channels 1 - 4 of the ES-2000/ES-3000 are equipped with the ability to transmit and receive the RTS/CTS handshake pair on the auxiliary communication lines. Jumpers J2 - J5 are used to enable or disable this feature as discussed below.

Transmission of RTS, when combined with reception of CTS, allows for handshaking between the PC and a peripheral device. RTS is transmitted by connecting pins 1 and 3 of the jumper block. CTS is received by connecting pins 2 and 4. The RTS/CTS handshake can be defeated by looping the RTS output back to the CTS input. This is accomplished by connecting pins 1 and 2.

AUXIN is the auxiliary input from a peripheral device. Connecting AUXIN to AUXOUT provides a loopback mode of operation. That is, whatever transmitted by the peripheral will be fed back out to the peripheral. This is implemented by connecting pins 3 and 4 of the jumper block.

Half Duplex Operation

Jumper J6 on the ES-2000/ES-3000 allows each of the communication channels to operate in half duplex mode. Half duplex mode allows the transmitter to be enabled and disabled using the data terminal ready (DTR)output controlled through the modem control registers of the 16552. When DTR is set (logic 1), the transmitter driver is enabled for both the data an auxiliary channel output (if applicable). When cleared (logic 0), the transmitter outputs enter a high impedance state. Full duplex operation is restored by removing the associated jumper on J6.

CAUTION: When operating in half duplex mode, the transmitter must be disabled before receiving any information. Failure to do so will result in two output drivers being connected together which may cause damage to the adapter, the computer, and/or the peripheral equipment.

Additional Addressing

The ES-2000/ES-3000 supports the entire I/O address range of the PS/2 occupying 64 consecutive I/O locations. This produces 1K possible choices for base address location. Since it would not be feasible or practical to provide all of these choices in the configuration file, 25 addresses have been selected for inclusion in the file. An address installation utility (QTINSTAL.EXE) has been included on the distribution diskette to facilitate the address installation process. QTINSTAL should be used ONLY if the desired base address cannot be found through the IBM installation utilities.

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