CompuScope SDK Manua.. - Egmont Instruments

PCI Bus CompuScopesPCI BusThe PCI bus is a processor-independent, multi-mastering 32 bit synchronous bus running at 33 MHz.The PCI bus can be found in almost any new personal computer, be it a Pentium-based or PowerPC orAlpha-based computer.A 64 bit extension of PCI is also becoming available. Similarly, 66 MHz bus speed will also be supportedby many motherboards.One of the main reasons for the popularity of PCI is the fast data throughput it offers between add-ondevices, such as video and SCSI controllers or CompuScope cards, and the CPU.The CompactPCI bus is electrically almost identical to the PCI bus but has a different mechanical formfactor and comes housed in an industrial quality chassis. CompactPCI (cPCI) card modules are installablefrom the front panel.PCI Local BusA Simplified Block DiagramPCI-ISA BridgePCI Slot 3PCI Slot 2ISA1ISA2ISANPCI Slot 1CPUCACHEPCIChipsetPCIChipsetSystem MemoryPlug-n-PlayAnother impressive feature that PCI brings to the PC platform is true plug-n-play capability. The user nolonger has to play with DIP switches to set addresses on the add-on cards — the system configures itself!At boot-up time, the PCI BIOS queries all add-on cards for the resources they need: I/O space, memoryspace, interrupts lines, etc. All add-on cards must be able to answer this query if they are to be deemed PCIcompatible.Once the BIOS knows the complete list of resources needed by the add-on cards, it configures the systemby assigning mutually exclusive resources to different add-on cards. All add-on cards must be able toaccept the base addresses provided by the BIOS for communicating with their resources.In other words, PCI cards must not be hard-wired to specific I/O or memory addresses or interrupt lines.CompuScope SDK Manual Page 11