Super I/O 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 it is mostly merged with EC.
The functions below are usually provided by the super I/O if they are on the motherboard:
- A floppy-disk controller
- An IEEE 1284-compatible parallel port (commonly used for printers)
- One or more 16C550-compatible serial port UARTs
- 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
- Thermal Zone
- Chassis intrusion detection
- Mainboard power management
- LED management
- PWM fan speed control
- An IrDA Port controller
- A game port (not provided by recent super I/O chips anymore because Windows XP is the last Windows OS to support a game port unless the vendor has a custom driver in the future OS)
- 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.
The original super I/O chips communicated with the central processing unit 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.
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 (has incorporated Winbond), ITE Inc., Fintek Inc. ,ENE Tech. (for laptop) and Microchip Technology (has incorporated SMSC™). National Semiconductor (Now Texas Instruments) 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 and brief
Many models are used for laptops with built-in keyboard controllers
- T8510E series
Microchip Technology (SMSC)
Microchip Technology provides Super I/O components with their SCH, MEC and LPC47 series. Here are some examples:
- lm_sensors contains a tool named sensors-detect that can also detect which Super I/O is used on a mainboard
- Embedded controller (EC)
- "Super I/O Chip Examples". Archived from the original on 2008-05-18.
- Constantine A. Murenin (2007-04-17). Generalised Interfacing with Microprocessor System Hardware Monitors. Proceedings of 2007 IEEE International Conference on Networking, Sensing and Control, 15–17 April 2007. London, United Kingdom: IEEE. doi:10.1109/ICNSC.2007.372901. ISBN 978-1-4244-1076-7. IEEE ICNSC 2007, pp. 901—906.
- Julien Bordet (2003). "it — ITE IT8705F/12F/16F and SiS SiS950 Super I/O Hardware Monitor". BSD Cross Reference. DragonFly BSD. Retrieved 2019-03-07.
- "it -- ITE IT8705F/12F/16F and SiS SiS950 Super I/O Hardware Monitor". DragonFly On-Line Manual Pages.
- Constantine A. Murenin (2010-05-21). OpenBSD Hardware Sensors — Environmental Monitoring and Fan Control (MMath thesis). University of Waterloo: UWSpace. hdl:10012/5234. Document ID: ab71498b6b1a60ff817b29d56997a418.
- Alexander Yurchenko (2005). "fins — Fintek F71805F LPC Super I/O". BSD Cross Reference. OpenBSD. Retrieved 2019-03-07.
- "fins — Fintek F71805F LPC Super I/O". OpenBSD manual page server.
- 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.