course ilt bus structures unit objectives describe the primary types of buses define interrupt, irq,...
TRANSCRIPT
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Bus structures
Unit objectives Describe the primary types of buses Define interrupt, IRQ, I/O address,
DMA, and base memory address Describe the features and functions of
the PCI bus, and install and configure a PCI adapter card
Describe the features and functions of the various video buses, and install and configure an AGP adapter card
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Topic A
Topic A: Buses Topic B: Host system interaction Topic C: The PCI bus Topic D: Video buses
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Buses
Communication pathway Four types
– Address– Data– Expansion– Video
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PCI bus slots
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An AGP video bus slot
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The riser bus
Brings the basic wiring and control of a function to a motherboard
Decreases cost Three riser standards:
– Advanced Communication Riser (ACR) – Audio/Modem Riser (AMR) – Communication and Networking Riser
(CMR)
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Activity A-1
Examining buses
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Topic B
Topic A: Buses Topic B: Host system interaction Topic C: The PCI bus Topic D: Video buses
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System interaction
Gain the attention of the CPU Access shared memory locations Extend the system BIOS Transfer data across the bus
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Interrupts
Signal CPU that attention is needed– CPU stops what it was doing– Services the device request– Returns to its previous task
Polling– Inefficient alternative to interrupts
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Running processes
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IRQs
Numerical addresses Help CPU identify interrupt source Enforce priority of interrupts Common IRQs
– IRQ 1: Keyboard– IRQ2: Cascade IRQs 9-15– IRQ4: COM1– IRQ6: Floppy– IRQ12: PS/2 mouse– IRQ14: Primary IDE hard drive
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Assigning IRQs
Manually assign for older PC designs– DIP switches– Jumpers– Proprietary software
Common for conflicts Plug and Play (PnP) in new PC
designs
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Device Manager - IRQs
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Activity B-1
Examining running processes and IRQ assignments
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I/O addresses
Identify section of shared memory Range of memory addresses Hexadecimal
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Device Manager–I/O addresses
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Activity B-2
Viewing your computer’s I/O address assignments
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DMA channels
DMA controller relieves CPU DMA channels Largely replaced by other techniques
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Device Manager–DMA channels
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Activity B-3
Viewing your computer’sDMA channel assignments
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Base memory addresses
Starting memory address of BIOS extensions– Display adapters– SCSI controllers– IDE controllers
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Device Manager–Base memory
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Activity B-4
Viewing your computer’s base memory address assignments
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Topic C
Topic A: Buses Topic B: Host system interaction Topic C: The PCI bus Topic D: Video buses
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PC/XT bus
8-bit bus– IBM PC and IBM XT
4.77 MHz clock speed 1.6 Mbps maximum data transfer rate
(0.4 MBps) Supported IRQs 0-8 Configured with DIP switches or
jumpers
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PC/XT card
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DIP switches and jumpers
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PC/AT and ISA bus
16-bit bus– IBM AT, clones, 80386/486, current PCs
8 MHz clock speed 8 MBps maximum data transfer rate
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ISA adapter
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ISA expansion bus slot
ISA slot
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PCI bus
32- or 64-bit bus– Pentium PCs
33 or 66 MHz clock speed 133-533 MBps maximum data transfer
rate Up to 8 functions on a single card Up to 5 card/slots per system Requires PnP
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PCI adapter
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PCI slots
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PCIe
Newer standard Uses serial communication Link Lanes x1 (by-one) x1, x2, x4, x8, x12, x16, and x32 bus
widths Can up-plug Can’t down-plug
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Activity C-1
Installing a PCI card
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Topic D
Topic A: Buses Topic B: Host system interaction Topic C: The PCI bus Topic D: Video buses
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Need for video buses
Older PC designs just used expansion bus
Graphical interfaces involve massive amounts of graphics data
Specialized buses developed to be fast enough
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VESA local bus
32- or 64-bit bus– Pentium PCs
33 or 66 MHz clock speed Popular on 80486-based PCs Generally software configurable No longer used
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VLB adapter
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AGP adapter
Note the hook
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AGP
Technically a port, not a bus 32-bit bus 33 or 66 MHz clock speed Speed “pumped” to as much as 533
MHz DIrect Memory Execute (DIME) 266-2133 MBps maximum data
transfer rate PnP configurable
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Activity D-1
Installing an AGP adapter
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Unit summary
Described the primary types of buses Defined interrupt, IRQ, I/O address,
DMA, and base memory address Described the features and functions
of the PCI bus, and installed and configure a PCI adapter card
Described the features and functions of the various video buses, and installed and configure an AGP adapter card