B&B Electronics PIOC User Manual

Not Recommended for New Installations.

Please contact Technical Support for more information.

Parallel Printer Card

Model PIOC

Documentation Number PIOC2595

This product

Designed and Manufactured

In Ottawa, Illinois

USA

of domestic and imported parts by

B&B Electronics Mfg. Co. Inc.

707 Dayton Road -- P.O. Box 1040 -- Ottawa, IL 61350

PH [phone] -- FAX [phone]

Internet:

http://www.bb-elec.com

[e-mail]

[e-mail]

 B&B Electronics -- Revised February 1995

Documentation Number PIOC2595 Manual Cover Page

B&B Electronics -- PO Box 1040 -- Ottawa, IL 61350

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Overview

The Parallel Printer Card (Model PIOC) is a bi-directional
parallel port for a standard IBM PC or compatible. The PIOC is
single port card that can be used as a printer interface or as a
general input/output port for any device. The base port address of
the card can be set for any address from 0 to 3FC hexadecimal.
This allows the card to be located at the standard parallel port
addresses, as well as any other unused address.

The PIOC can have up to 12 digital TTL compatible outputs and
up to 17 digital TTL compatible inputs. 12 of these inputs and
outputs share connector pins so you cannot have 12 inputs and 17
outputs at the same time. The input/output lines are available
through a female DB-25 connector.

To understand how the PIOC can be used you must first
understand how the IBM PC parallel port works from inside the
computer. Each parallel port has one main port address for
outputting data, the Base Register. The next two addresses above
that address are used for handshaking control. The first address is
the Status Register, and the second address is the Control Register.
For instance, on a typical computer LPT1 might be located at
hexadecimal address 378h, which is the Base Register. The Status
Register will be located at 379h and the Control Register will be
located at 37Ah. Table 1 shows the functions of each pin on the DB­25 connector when the PIOC is connected to a printer.

Documentation Number PIOC2595 Manual 1

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Table 1 - Printer Functions

PIOC DB-25
Connector

1 Strobe
2 Data Bit 1
3 Data Bit 2
4 Data Bit 3
5 Data Bit 4
6 Data Bit 5
7 Data Bit 6
8 Data Bit 7
9 Data Bit 8
10 Acknowledge
11 Busy
12 Paper End
13 Select
14 Auto Feed
15 Error
16 Initialize Printer
17 Select Input
18 - 25 Ground

Printer
Function

Setting the Address

The base address of the PIOC is set using a eight-position DIP
switch, SW1. The eight positions correspond to the I/O address lines
of A2 through A9 (see Table 2). If you set the a switch OFF the
corresponding I/O address line will be a ZERO and if you set it ON
the corresponding I/O address line will be a ONE. The factory
default address setting is 378h. To set the card to the 378h address
you must set A2 and 7 OFF and A3, 4, 5, 6, 8, and 9 ON. Table 3
shows the settings for LPT1 and LPT2.

2 Documentation Number P I OC2595 Manual

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Table 2 - DIP Switch Functions

SW1 I/O Address

1 A9
2 A8
3 A7
4 A6
5 A5
6 A4
7 A3
8 A2

Table 3 - DIP Switch Weights

SW1 1 2 3 4 5 6 7 8 X X
Address:
Weight:
LPT1 (378h):
LPT2 (278h):

A9 A8 A7 A6 A5 A4 A3 A2 A1 A0

2 1 8 4 2 1 8 4 2 1
1 1 0 1 1 1 1 0 0 0
1 0 0 1 1 1 1 0 0 0

NOTE: A "1" indicates that the switch is ON and a "0"indicates that
the switch is OFF.

Documentation Number PIOC2595 Manual 3

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Table 4 - Hardware I/O Map of AT Class Machines

Hex Address Address Function in AT Class Machines
000-01F
020-03F
040-05F
060-06F
070-07F
080-09F
0A0-0BF
0C0-0DF
0F0-0FF
1F0-1F8
200-20F
258-25F
278-27F
2E8-2EF
2F8-2FF
300-31F
378-37F
380-38F
3A0-3AF
3B0-3BF
3BC-3BE
3C0-3CF
3D0-3D7
3E8-3EF
3F0-3F7
3F8-3FF

DMA controller #1 (8237A-5)
interrupt controller #1 (8259A)
timer (8254)
keyboard (8042)
NMI - non maskable interrupt & CMOS RAM
DMA page register (74LS612)
interrupt controller #2 (8259A)
DMA controller #2 (8237A)
80287 math coprocessor
hard disk
game port joystick controller
Intel Above Board
parallel printer port 2
COM4 serial port
COM2 serial port
prototype card
parallel printer 1
SDLC or bisynch com 2
bisynch com 1
MDA - monochrome adapter
parallel printer on monochrome adapter
EGA - reserved
CGA - color graphics adapter
COM 3 serial port
floppy diskette controller
COM1 serial port

Any four byte space not listed in Table 4 and not used by any
other equipment in your system may be used for the parallel port.
Appendix A shows all the possible addresses and their settings.

4 Documentation Number P I OC2595 Manual

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