The purpose of the IT-20 is to provide low-cost, flexible technology to introduce computer interfacing to students. The IT-20 consists of two boards-the large board shown above connected via cable to the small buffer board plugged into the ISA bus. Part of the ISA bus is present at the connector on the large board providing the interface signals to the components on the board. The IT-20 can be configured for many different experiments to give students a broad experience in computer interfacing and in writing device drivers.

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IT-20 Training Board Menu (Note: Our remaining inventory is on sale--contact us for a quote)

 IT-20 Board Overview

 IT-20 Components

 Examples of experiments using the IT-20

 Price, ordering, and contact information

 Another photo of the IT-20, including options 

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IT-20 Board Overview 

Connect the IT-20 to the IT-20B buffer board inside the PC via ribbon cable, and you're ready to begin.
The IT-20 lab manual contains self-paced lab exercises, complete circuit descriptions, and a disk of sample programs. Extra copies of the manual may be ordered.
The IT-20's open, tabletop design allows hands-on study of a variety of common interfacing tasks and allows you to monitor signals in real time with a voltmeter or oscilloscope for debugging or educational purposes.
By switching jumpers on the IT-20, you can configure more than 20 different interfacing exercises with no additional components. Furthermore, the board's flexible design provides 24 uncommitted digital I/O pins, expanded interrupts, and 8 A/D channels for custom interfacing designs.
The chips and other components of the IT-20 are widely used in PC technology. By familiarizing students with these components, the IT-20 prepares them to use PCs more effectively in general.
Use of the PC and 80X86 architecture in embedded system and control applications is a large and growing field. Students familiar with PC architecture and interfacing techniques will have a definite advantage.
The IT-20 has been designed with college budgets in mind. The high-quality IT-20 is produced economically, without the packaging and advertising that typically drive up the prices of computer-related products.


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IT-20 Components  

An 8253A counter/timer consisting of 3 independent, 16-bit counter/timers.

Two 8255A peripheral interface adapters, each containing 24 programmable digital I/O pins. One of these chips is used by the board, and the other (24 pins) is free for use by the experimenter.

An electret condenser microphone.

An ADC809 8-bit, analog-to-digital converter containing 8 multiplexed analog inputs.

A DAC831 8-bit, digital-to-analog converter with a settling time of 1 m s.

An LM389 low-power audio amplifier and a 2-inch speaker. The audio amplifier can be fed from the three outputs of the counter/timer or from the DAC831.

An LM335 precision temperature sensor.

An 8259A programmable interrupt controller containing 8 prioritized interrupt request lines for interrupt expansion.

One uncommitted operational amplifier from the LM324 quad op-amp chip.

A simple 16-key, contact-closure keypad.

Eight LEDs.

An optional stepping motor and on-board stepping motor driver. No external power supply is necessary.

A 2x3.5-inch plug-in prototyping area.


IT-20 main board: 8"x10" mounted on 1/2" standoffs.
IT-20B buffer board: fits in a short card slot on the PC's ISA bus.
All IT-20 and IT-20B components are socketed.


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Examples of experiments using the IT-20 (configured using jumpers)

Using the 8253A counter/timer

generating frequencies (sound can be heard on speakers)
driving the stepper motor
generating interrupt requests
initiating A/D conversion

 Using the ADC809 A/D converter

sampling the on-board potentiometer
measuring the temperature, using the supplied LM335
using the end-of-conversion signal to generate an interrupt or DMA request
(all 8 inputs can be connected to the external sources)
sampling sound with the on-board microphone

Using the DAC831 D/A converter

generating waveforms (sound can be heard on speaker)
generating control voltages for external equipment
playing digitally sampled sound 

Using the system DMA controller (8237A)

transferring data from A/D converter to memory buffer on any A/D channel 

Using the two 8255A peripheral interface expanders

reading the on-board keypad
turning on the LEDs
controlling the counter/timer gates
controlling the stepper motor
using the 24 uncommitted digital I/O pins to control external devices 

Using the 8259A programmable interrupt controller

expanding interrupts beyond those in the system
connecting interrupt request lines to the digital I/O or counter/timer outputs 

Using the on-board microphone

digitally recording and playing back sound using A/D and D/A


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Price, ordering, and contact information-(Note: Our remaining inventory is on sale--contact us for a quote)

A. Complete IT-20 including lab manual and disk-- $445.00 

B. Optional stepping motor and driver-- $55.00 

C. Optional wooden case with plexiglass cover-- $85.00 

D. Extra copies of lab manual-- $22.95 

E. "Handbook of Software and Hardware Interfacing for IBM PCs," by Jeffrey P. Royer, 1987-- $28.95 

F. Disk of source programs for the above book-- $19.95

 All products are warranted against defects for 90 days. 

Payments may be by check, money order, or purchase order to:

Royer Associates
542 Santa Barbara Road
Berkeley CA, 94707

Purchase orders will be accepted from institutions and corporations. Include 5% for shipping and handling. California residents add sales tax. Purchase orders may be faxed to (510) 526-7895 (please call first at number below).

Please call (510) 526-7861 if you have questions.


Over 1000 IT-20s are in use in colleges, universities, and technical programs worldwide.

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A photo showing all the components of the IT-20, including the optional stepping motor and hardwood case. 



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