Computer Architecture CST 250

1. Computer ArchitectureCST 250 BUS & EXPANSION CARDS ARCHITECTURE Prepared by:Omar Hirzallah

2. Contents • BUS Architecture • Data Bus • Address Bus • Control Bus • Expansion Cards • PCI, MCA, ISA • EISA, VESA, AGP

3. BUS ARCHITECTURE PROCESSOR MEMORY Address Bus Data Bus Control Bus Input / Output

4. DATA BUS: The data bus is used to move the data between the various components (e.g. CPU, Memory, Input & Output Devices) in the system. Processor Types and Associated Data Bus Widths Size of 1 Read Operations

5. ADDRESS BUS:The CPU uses it to send the Physical addresses of computer memory to different units of computer. CPU also use it to locate memory or I/O devices. The width of The address determines the maximum size of memory. Processor Types and Associated Address Bus Widths

6. CONTROL BUS:It is used to carry control signals from the processor to other components of the system. Here are some examples of control signal notations generated by processor. W/R ----- Write / Read IRQ ----- Interrupt Request EXPANSION CARDS:

7. Expansion cards • PCI: Peripheral component interconnect. • 32 bit bus card. • Runs at 33Mhz • It has connectors similar to those on MCA and EISA cards. • PCI slot will not accept ISA or 8 bit cards. • Supports PnP ( plug and play) • PCI Express: • MCA: Micro channel • Developed by IBM. • Include circuit which looks like PnP. • ISA: Industry Standard Architecture. • 16 bit data lines. • Speed 8 MHz • Doesn’t support PnP.

8. Expansion cards • EISA: Extended Industry Standard • Compatible with ISA. • 32 bit data line. • Supports PnP. • Performance is low. • VESA: Video Electronic standard Association • 32 data line. • Speed of 33 MHz. • Designed to work with Intel 486 processor and not with Pentium. • Doesn’t support PnP. • AGP: Accelerated Graphics port. • It is designed for graphics communication.