PCI Buses Peripheral Component Interconnect Interface

Typical PCI Card

Most PCs have two sets of buses –System bus or local bus Connects the microprocessor with the system memory –Other buses (ISA, PCI, etc…) Connect to the system bus via a bridge –Bridge integrates the data from the bus with the data from the system bus

Dual Independent Buses

Buses Backside Bus –Provides a fast direct channel between CPU and Level 2 Cache Frontside Bus –Connected to Memory via a memory controller –Connected to CPU –Connected to other buses via a bridge

Another Main Bus Shared Bus –Allows many peripherals connected to it to connect to CPU and memory Modems Hard Drive Sound Card Graphics Card Controller Card Scanner

Bus History Original Bus –8-bits wide –Operated at 4.77MHz ISA (Industry Standard Architecture – 1982) –16 bits wide –8MHz EISA (Extended ISA) –32 bits wide –8 MHz VL –Bus (VESA Local Bus) –32 bits wide –Operated at processor speed

PCI Uses 47 Pins

Bus TypeBus WidthBus SpeedMB/sec ISA16 bits8 MHz16 MBps EISA32 bits8 MHz32 MBps VL-bus32 bits25 MHz100 MBps VL-bus32 bits33 MHz132 MBps PCI32 bits33 MHz132 MBps PCI64 bits33 MHz264 MBps PCI64 bits66 MHz512 MBps PCI64 bits133 MHz1 GBps