until it observed SDONE high. In the case of a write to data that was clean in the cache, the cache would only have to invalidate its copy, and would assert SDONE as soon as this was established. However, if the cache contained dirty data, the cache would have to write it back before the access could proceed. so it would assert SBO# when raising SDONE. This would signal the active target to assert STOP# rather than TRDY#, causing the initiator to disconnect and retry the operation later. In the meantime, the cache would arbitrate for the bus and write its data back to memory. Targets supporting cache coherency are also required to terminate bursts before they cross cache lines. Development tools When developing and/or troubleshooting the PCI bus, examination of hardware signals can be very important. Logic analyzers and bus analyzers are tools which collect, analyze, and decode signals for users to view in useful ways. See also PCI configuration space CompactPCI, PCI-X, PCI Express PCI-SIG, PCI Special Interest Group PICMG, PCI Industrial Computer Manufacturers Group Eurocard (printed circuit board) References Further reading Official technical specifications ($1000 for non-members or $50 for members. PCI-SIG membership is $3000 per year.) ($1000 for non-members or $50 for members. PCI-SIG membership is $3000 per year.) Books 250 pages. 832 pages. 752 pages. 1140 pages. 162 pages. External links Official , PCI Special Interest Group (PCI-SIG) Technical Details Introduction to PCI protocol , electrofriends.com PCI bus pin-out and signals, pinouts.ru PCI card dimensions, interfacebus.com Lists of Vendors, Devices, IDs PCI Vendor and Device Lists, pcidatabase.com PCI ID Repository, a project to collect all known IDs Tips Brief overview of PCI power requirements and compatibility with a nice diagram Good diagrams and text on how to recognize the difference between 5 volt and 3.3 volt slots Linux Linux with miniPCI cards Decoding PCI data and lspci output on Linux hosts Development Tools Active PCI Bus Extender, dinigroup.com FPGA Cores PCI Interface Core, Lattice Semiconductor . . Peripheral Component Interconnect Motherboard expansion slot Macintosh internals IBM PC compatibles Wikipedia articles with ASCII art Computer-related introductions in 1993