engineering

Super I/O

Super I/O is a engineering 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 Super I/O rather than just read about it. In short: Super I/O (sometimes Multi-IO) is a class of I/O controller integrated circuits that began to be used on personal computer motherboards in the late 1980s, originally as add-in cards, later embedded on the motherboards. A super I/O chip combines interfaces for a variety of low-bandwidth devices.

Key takeaways

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

Reference excerpt

Super I/O (sometimes Multi-IO) is a class of I/O controller integrated circuits that began to be used on personal computer motherboards in the late 1980s, originally as add-in cards, later embedded on the motherboards. A super I/O chip combines interfaces for a variety of low-bandwidth devices. Now the I/O controller that combined Super I/O function and Embedded Controller function is called embedded Super I/O (eSIO).

Functions The functions below are usually provided by the super I/O if the motherboard has these functions:

A floppy-disk controller An IEEE 1284-compatible parallel port (commonly used for printers) One or more 16C550-compatible serial port UART's Keyboard controller for PS/2 keyboard and/or mouse Most Super I/O chips include some additional low-speed devices, such as:

Temperature, voltage, and fan speed interface Connect temperature and voltage sensors via SMBus Thermal Zone Chassis intrusion detection Mainboard power management, including control voltage regulator module LED management PWM fan speed control An IrDA Port controller A game port (not provided by recent super I/O chips because Windows XP is the last Windows OS to natively support game ports, requiring vendors to supply their own drivers for later Windows operating systems) A watchdog timer A consumer IR receiver A MIDI port Some GPIO pins Legacy Plug and Play or ACPI support for the included devices By combining many functions in a single chip, the number of parts needed on a motherboard is reduced, thus reducing the cost of production.

History The original super I/O chips communicated with the central processing unit (CPU) via the ISA bus. With the evolution away from ISA towards use of the PCI bus, the Super I/O chip was often the biggest remaining reason for continuing inclusion of ISA on the motherboard. Later super I/O chips use the LPC bus instead of ISA for communication with the central processing unit. This normally occurs through an LPC interface on the Southbridge chip of the motherboard. Since Intel is replacing the LPC bus with the eSPI bus, super I/O chips that connect to that bus have appeared on the market. Companies that make super I/O controllers include Nuvoton (spun off from Winbond), ITE Inc., Fintek Inc. ,ENE Tech. (for laptop) and Microchip Technology (which bought SMSC™). National Semiconductor used to make super I/O controllers but sold that business to Winbond at 2005, which already had a competing super I/O controller business. In 2008, Winbond then spun off its logic businesses to a wholly owned subsidiary, Nuvoton. SMSC made super I/O chips and then got acquired by Microchip Technology.

Common models

ENE Tech. Many models are used for laptops with built-in keyboard controllers

KB3930 KB930QF

ITE Inc. T8510E series

Microchip Technology (SMSC) Microchip Technology provides Super I/O components with their SCH, MEC and LPC47 series. Here are some examples:

SCH3112 SCH3114 SCH3116 SCH3223

Nuvoton Technology (Winbond) NCT6776

See also envsys hw.sensors lm_sensors contains a tool named sensors-detect that can also detect which Super I/O is used on a mainboard SpeedFan Embedded controller (EC)

References

External links Superiotool is a Linux user-space tool to detect which Super I/O is used on a mainboard, and it can provide detailed information about its register contents.

Illustrations

Worked examples

Example 1 — a first encounter with Super I/O

Start with the simplest possible case. Write down what Super I/O claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, 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 Super I/O 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 Super I/O 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 Super I/O

In research: Super I/O appears in engineering 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 Super I/O 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: Super I/O is common in secondary-school and first-year university syllabi. It links to neighbouring topics Input/output integrated circuits, Motherboard, so understanding it makes those chapters shorter.
In everyday life: Look for Super I/O 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 Super I/O in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Super I/O 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 Super I/O out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Super I/O in simple terms?

Why does Super I/O matter?

Because it connects several engineering 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 Super I/O?

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 Super I/O.