Detailed Installation; Base Address - Omega CIO-CTR10 User Manual

Expansion boards

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Table of Contents

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ELECTRONICS AND INTERFACING

VOLTAGE DIVIDERS

If you wish to measure a signal which varies over a range greater than the input range

of a digital input, a voltage divider can drop the voltage of the input signal to the level

the digital input can measure.

A voltage divider takes advantage of Ohm's law, which states,

Voltage = Current * Resistance

and Kirkoff's voltage law which states,

The sum of the voltage drops around a circuit will be equal to the voltage drop for the

entire circuit.

SIGNAL HIGH

SIGNAL

Vin

VOLTS

SIGNAL LOW

SIMPLE VOLTAGE DIVIDER

Implied in the above is that any variation in the voltage drop for the circuit as a whole

will have a proportional variation in all the voltage drops in the circuit.

Vin

R1 + R2

Vout

A/D BOARD

HIGH INPUT

Vout

A/D BOARD

LOW INPUT

We highly recommend that you use the InstaCAL procedure described in the previous

chapter to guide you through setting up your board. However, the following sections

are provided in case you need to set up your board and you do not have access to the

InstaCAL program.

The CIO-CTR has one bank of switches, a base address switch, and one jumper block

which must be set before installing the board in your computer. The calibration and

test program included with the CIO-CTR will show how these switches are to be set

and should be run before you open your computer.

BASE ADDRESS

Unless there is already a board in your

system which uses address 300 HEX

(768 Decimal) then you can leave the

switches as they are set at the factory.

In the example shown here, the CIO-

CTR is set for base address 300H (768

Decimal).

Certain address are used by the PC, others are free and may be used by the CIO-CTR

and other expansion boards. We recommend BASE = 300H (768D) be tried first.

HEX

FUNCTION

RANGE

000-00F

8237 DMA #1

020-021

8259 PIC #1

040-043

8253 TIMER

060-063

8255 PPI (XT)

060-064

8742 CONTROLLER (AT)

070-071

CMOS RAM & NMI

MASK (AT)

080-08F

DMA PAGE REGISTERS

0A0-0A1

8259 PIC #2

0A0-0AF

NMI MASK (XT)

0C0-0DF

8237 #2 (AT)

0F0-0FF

80287 NUMERIC CO-P

(AT)

1F0-1FF

HARD DISK (AT)