The System Management Bus (abbreviated to SMBus or SMB) is a single-ended simple two-wire bus for the purpose of lightweight communication. Most commonly it is found in computer motherboards for communication with the power source for ON/OFF instructions.
It is derived from I²C for communication with low-bandwidth devices on a motherboard, especially power related chips such as a laptop's rechargeable battery subsystem (see Smart Battery Data). Other devices might include temperature, fan or voltage sensors, lid switches and clock chips. PCI add-in cards may connect to a SMBus segment.
A device can provide manufacturer information, indicate its model/part number, save its state for a suspend event, report different types of error, accept control parameters and return status. The SMBus is generally not user configurable or accessible. Although SMBus devices usually can't identify their functionality, a new PMBus coalition has extended SMBus to include conventions allowing that.
The SMBus was defined by Intel in 1995. It carries clock, data, and instructions and is based on Philips' I²C serial bus protocol. Its clock frequency range is 10 kHz to 100 kHz. (PMBus extends this to 400 kHz.) Its voltage levels and timings are more strictly defined than those of I²C, but devices belonging to the two systems are often successfully mixed on the same bus.
SMBus is used as an interconnect in several platform management standards including: ASF, DASH, IPMI.
Read more about System Management Bus: SMBus/I²C Interoperability, SMBus Support
Famous quotes containing the words system, management and/or bus:
“He is not a true man of science who does not bring some sympathy to his studies, and expect to learn something by behavior as well as by application. It is childish to rest in the discovery of mere coincidences, or of partial and extraneous laws. The study of geometry is a petty and idle exercise of the mind, if it is applied to no larger system than the starry one.”
—Henry David Thoreau (1817–1862)
“The Management Area of Cherokee
National Forest, interested in fish,
Has mapped Tellico and Bald Rivers
And North River, with the tributaries
Brookshire Branch and Sugar Cove Creed:
A fishy map for facile fishery....”
—Allen Tate (1899–1979)
“An actor rides in a bus or railroad train; he sees a movement and applies it to a new role. A woman in agony of spirit might turn her head just so; a man in deep humiliation probably would wring his hands in such a way. From straws like these, drawn from completely different sources, the fabric of a character may be built. The whole garment in which the actor hides himself is made of small externals of observation fitted to his conception of a role.”
—Eleanor Robson Belmont (1878–1979)