HP Workstation x2000 hp workstation x2000 - Technical Reference and Troublesho - Page 61

Figure 2-9 System Board The Input/Output Controller Hub 2 (82801BA) CS4280-CS4297 and CS4299 Architecture Previous Architecture North Bridge South Bridge PCI Slots PCI Bus New Architecture North Bridge South Bridge CS4280 digital controller Audio controller link Audio controller link CS4299 CS4297 Devices on the SMBus The SMBus is a subset of the I2C bus. It is a two-wired serial bus that runs at a maximum speed of 100KHz. The SMBus monitors some of the system board's hardware functions (for example, voltage levels, temperature, fan speed, memory presence, and type), both at system boot and during normal run-time. The SMBus controller, located in the ICH2, controls the SMBus. The following devices are connected to the SMBus: • LCD status panel • One serial EEPROM MaxiLife (also includes backup values of CMOS settings) • PCI slot 5, thus being ready for Alert-On LAN (AOL) from a hardware level • ICH2 SMBus master controller 100KHz maximum • MaxiLife for hardware management, bus master controller • One LM75 thermal sensor on the system board • One ADM1024 hardware-monitoring sensor Chapter 2 61