Measurement Alpha488 User Manual

Alpha488 (IEA11)

Interface Card

Hardware Guide

Part #: 419-0920

Revision 1.0, 7/96

IOtech, Inc. n 25971 Cannon Road n Cleveland, Ohio 44146 n [phone]

Warranty

Your IOtech warranty is as stated on the product warranty card. You may contact IOtech by
phone, fax machine, or e-mail in regard to warranty-related issues.
Phone: [phone], fax: [phone], email:

[e-mail]

Limitation of Liability

IOtech can not be held liable for any damages resulting from the use of this product.

Copyright Notice

All IOtech documentation, software, and circuit boards are copyrighted with all rights
reserved by IOtech. No part of this product may be copied, reproduced or transmitted by
any mechanical, photographic, electronic or other method without prior written consent of
IOtech, Inc.

Trademark Notice

Alpha488 is a registered trademark of IOtech, Inc. All other product names are
trademarks or registered trademarks of their respective holders.

Printed in the United States of America.

Alpha488 (IEA11) Hardware Guide

Hardware Installation

The following paragraphs explain configuration and physical installation of the interface
card. Software installation and setup are covered in a separate section. After running the
ECU, please make note of the following: the I/O Base Address, the interrupt channel, and
the DMA channel.

The Alpha488 has two DIP switches (S1 and S2), one 22 pin header (IRQ), and two
14-pin headers (DACK and DRQ). The DIP switch settings, along with the arrangement
of the jumpers on the headers, set the hardware configuration.

Default Settings

Notice that S2 and IRQ set the interrupt response level, S1 controls the I/O base address,
and DACK and DRQ select the DMA channel.

Alpha488 I/O Base Address Selection

The I/O base address sets the addresses used by the computer to communicate with the
IEEE 488 interface hardware on the board. The address is normally specified in
hexadecimal and can be 02E1, 22E1, 42E1, or 62E1. The registers of the NEC µPD7210
IEEE 488 controller chip and other auxiliary registers are then located at fixed offsets
from the base address.

The factory default I/O base address is 02E1. To use a different base address, set S1
according to Figure 1.

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Figure 1. Alpha488 I/O Base Address Settings

Interrupt Selection

The main board interrupt may be set to IRQ level 3 through 7, 10, 11, 12, 14, or 15.
When the Alpha488 requires service, the IRQ jumper determines which interrupt level is
triggered. When an interrupt occurs, the interrupting device must be reset by writing to an
I/O address which is different for each interrupt level. The switch settings determine the
I/O address to which the board’s interrupt rearm circuitry responds. The IRQ jumper and
switch settings must both indicate the same interrupt level for correct operation with
interrupts. Figure 2 shows the settings for selected interrupts.

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Figure 2. Alpha488 Interrupt Selection

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DMA Channel Selection

The Alpha488 has seven DMA channels. Channels 0-3 (8-bit), 5, 6, and 7
(16-bit) are available. Both the DRQ and DACK jumpers must be set to the desired DMA
channel for proper operation. Configure the board according to which DMA channel is
available. Figure 3 shows settings for selecting the DMA channels.

Figure 3. Alpha488 DMA Selection

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