computer science

Peripheral Interface Adapter

Peripheral Interface Adapter is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Peripheral Interface Adapter rather than just read about it. In short: A Peripheral Interface Adapter (PIA) is a peripheral integrated circuit providing parallel I/O interfacing for microprocessor systems. Description Common PIAs include the Motorola MC6820 and MC6821, and the MOS Technology MCS6520, all of which are functionally identical but have slightly different electrical characteristics.

Key takeaways

Peripheral Interface Adapter belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Peripheral Interface Adapter to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Peripheral Interface Adapter from memory before moving on to harder problems.

Reference excerpt

A Peripheral Interface Adapter (PIA) is a peripheral integrated circuit providing parallel I/O interfacing for microprocessor systems.

Description Common PIAs include the Motorola MC6820 and MC6821, and the MOS Technology MCS6520, all of which are functionally identical but have slightly different electrical characteristics. The PIA is most commonly packaged in a 40 pin DIP package. The PIA is designed for glueless connection to the Motorola 6800 style bus, and provides 20 I/O lines, which are organised into two 8-bit bidirectional ports (or 16 general-purpose I/O lines) and 4 control lines (for handshaking and interrupt generation). The directions for all 16 general lines (PA0-7, PB0-7) can be programmed independently. The control lines can be programmed to generate interrupts, automatically generate handshaking signals for devices on the I/O ports, or output a plain high or low signal. In 1976 Motorola switched the MC6800 family to a depletion-mode technology to improve the manufacturing yield and to operate at a faster speed. The Peripheral Interface Adapter had a slight change in the electrical characteristics of the I/O pins so the MC6820 became the MC6821. The MC6820 was used in the Apple I to interface the ASCII keyboard and the display. It was also deployed in the 6800-powered first generation of Bally electronic pinball machines (1977-1985), such as Flash Gordon and Kiss. The MCS6520 was used in the Atari 400 and 800 and Commodore PET family of computers (for example, to provide four joystick ports to the machine). The Tandy Color Computer uses two MC6821s to provide I/O access to the video, audio and peripherals.

References Leventhal, Lance A. (1986). 6502 Assembly Language Programming 2nd Edition. Osborne/McGraw-Hill. ISBN 0-07-881216-X.

Illustrations

Worked examples

Example 1 — a first encounter with Peripheral Interface Adapter

Start with the simplest possible case. Write down what Peripheral Interface Adapter claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Peripheral Interface Adapter before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Peripheral Interface Adapter ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Peripheral Interface Adapter

In research: Peripheral Interface Adapter appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Peripheral Interface Adapter in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Peripheral Interface Adapter is common in secondary-school and first-year university syllabi. It links to neighbouring topics Computer hardware stubs, Input/output integrated circuits, so understanding it makes those chapters shorter.
In everyday life: Look for Peripheral Interface Adapter outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Peripheral Interface Adapter in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Peripheral Interface Adapter means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Peripheral Interface Adapter out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Peripheral Interface Adapter in simple terms?

A Peripheral Interface Adapter (PIA) is a peripheral integrated circuit providing parallel I/O interfacing for microprocessor systems. Description Common PIAs include the Motorola MC6820 and MC6821, and the MOS Technology MCS6520, all of which are functionally identical but have slightly different…

Why does Peripheral Interface Adapter matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Peripheral Interface Adapter?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Peripheral Interface Adapter.