system management bus (SMBus)
The System Management Bus (SMBus) is a control bus that was jointly developed by Intel and Duracell and standardized in 1993. It is used for communication at chip level and essentially corresponds to the I2C bus. This also means that the components of both buses are compatible with each other.
The status of hardware components is transmitted via the SMBus. In addition, messages and control signals for component activation and deactivation can be transmitted via this bus. Used in Smart Batteries and Smart Battery Chargers( SBC), the current status, State of Health ( SoH), and State of Charge( SoC) of batteries can be transmitted via the SMBus. Other connectable components include Electrically Erasable PROMs( EEPROM), temperature sensors, digital potentiometers, etc.
The SMBus is based on the I2C bus, which operates in master- slave mode with several master stations and supports bidirectional communication between master and slaves. Like the I2C bus, the SMBus works with a two- wire line: a data line (SMBDAT) and a line for the clock signal (SMBCLK). There are three additional lines for the supply voltage and ground. In addition, the SMBus has an error control for checking the transmitted data. This procedure is called Packet Error Check( PEC) and works with cyclic block check. In contrast to the I2C bus, the SMBus has timeout and alarm.
The SMBus is used in motherboards, among other things, it has a data rate of 100 kbit/s and is supported by the interface for power management, Advanced Configuration and Power Interface( ACPI).