HP dc7900 Parallel Interface Support, Standard Parallel Port Mode, Enhanced Parallel Port Mode

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Input/Output Interfaces

5.5Parallel Interface Support

The SFF and CMT form factors include a system board header (J50) that supports an optional parallel bracket/cable assembly that provides a parallel interface for a peripheral device such as a printer. The parallel interface supports bi-directional 8-bit parallel data transfers with a peripheral device. The parallel interface supports three main modes of operation:

■Standard Parallel Port (SPP) mode

■Enhanced Parallel Port (EPP) mode

■Extended Capabilities Port (ECP) mode

These three modes (and their submodes) provide complete support as specified for an IEEE 1284 parallel port.

5.5.1 Standard Parallel Port Mode

The Standard Parallel Port (SPP) mode uses software-based protocol and includes two sub-modes of operation, compatible and extended, both of which can provide data transfers up to 150 KB/s. In the compatible mode, CPU write data is simply presented on the eight data lines. A CPU read of the parallel port yields the last data byte that was written.

5.5.2 Enhanced Parallel Port Mode

In Enhanced Parallel Port (EPP) mode, increased data transfers are possible (up to 2 MB/s) due to a hardware protocol that provides automatic address and strobe generation. EPP revisions 1.7 and 1.9 are both supported. For the parallel interface to be initialized for EPP mode, a negotiation phase is entered to detect whether or not the connected peripheral is compatible with EPP mode. If compatible, then EPP mode can be used. In EPP mode, system timing is closely coupled to EPP timing. A watchdog timer is used to prevent system lockup.

5.5.3 Extended Capabilities Port Mode

The Extended Capabilities Port (ECP) mode, like EPP, also uses a hardware protocol-based design that supports transfers up to 2 MB/s. Automatic generation of addresses and strobes as well as Run Length Encoding (RLE) decompression is supported by ECP mode. The ECP mode includes a bi-directional FIFO buffer that can be accessed by the CPU using DMA or programmed I/O. For the parallel interface to be initialized for ECP mode, a negotiation phase is entered to detect whether or not the connected peripheral is compatible with ECP mode. If compatible, then ECP mode can be used.

The ECP mode includes several sub-modes as determined by the Extended Control register. Two submodes of ECP allow the parallel port to be controlled by software. In these modes, the FIFO is cleared and not used, and DMA and RLE are inhibited.

 

Technical Reference Guide

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Contents September Technical Reference GuideTechnical Reference Guide Contents Input/Output Interfaces Processor/Memory SubsystemSystem Support Integrated Graphics Subsystem Power and Signal DistributionError Messages and Codes Index System BiosOnline Viewing IntroductionAbout this Guide Additional Information SourcesValues Serial NumberNotational Conventions Special NoticesAcronyms and Abbreviations Acronym or Description Common Acronyms and AbbreviationsCmos CDSCGA CMCEscd EisaEPP EideLCD IRQISA LANPCA ODDPAL PataSgram SdvoSEC SecamAcronym or Abbreviation Description Acronyms and AbbreviationsIntroduction Introduction System OverviewFeatures 1ODD Feature Difference Matrix by Form FactorSodimm Dimm Function System ArchitectureArchitectural Differences By Form Factor HP Compaq dc7900 Business PC Architecture, Block diagram Intel Processor Support Components Function ChipsetChipset Components and Functionality Component Name Function Support ComponentsSystem Memory Support Component FunctionsNetwork Interface Controller Mass StorageSerial Interface Universal Serial Bus InterfaceIntegrated Graphics Controller Graphics SubsystemAudio Subsystem Integrated Graphics Subsystem StatisticsParameter Operating Non-operating SpecificationsEnvironmental Specifications Factory Configuration Power Supply Electrical SpecificationsParameter Usdt SFF CMT Physical SpecificationsCD-RW/DVD-ROM Combo Optical Drive SpecificationsHP SuperMulti LightScribe ParameterParameter 80 GB 160 GB 250 GB Hard Drive SpecificationsProcessor/Memory Subsystem Architecture Processor/Memory SubsystemIntel Processor Overview Intel ProcessorsForm Processor Changing/UpgradingSupported Processors partial listing ClockMemory Subsystem Channel a Channel B Socket Socket 2 Socket 4 Total Memory UpgradingMemory Mapping and Pre-allocation Memory Socket LoadingSystem Memory Map for maximum of 8 gigabytes PCI 2.3 Bus Operation System SupportPCI Bus Overview PCI Component Function # Device # Wired to PCI Component Configuration Access PCI BusPCI Bus Mastering Devices PCI Express Bus OperationSoftware/Driver Layer Transaction Protocol LayerLink Layer PCI Power Management SupportOption ROM Mapping PCI InterruptsPCI 2.3 Bus Connector Pinout PCI ConnectorsPCI 2.3 Connector PCI Express Bus Connector Pinout PCI Express ConnectorsMode Apic ModeSystem Resources InterruptsPCI Interrupt Distribution Direct Memory AccessClearing Cmos Real-Time Clock and Configuration MemorySecurity Functions Configuration Memory Cmos MapSystem Management Standard Cmos LocationsInterface Security Power-On / Setup PasswordSetup Password Cable Lock ProvisionAcpi Wake-Up Event System Wakes From Power ManagementSmart Cover Lock Optional Acpi Wake-Up EventsSystem Operational Status LED Indications System Status PowerLED Beeps Action RequiredSystem Status Thermal Sensing and CoolingSystem I/O Map Register Map and Miscellaneous FunctionsPort Function System I/O MapSIO Controller Functions Gpio FunctionsICH10 Functions Input/Output Interfaces Pin Description Pin Sata Connector PinoutSATA/eSATA Interfaces Sata interfaceESATA interface Optional eSATA Bracket/Cable AssemblyDiskette Drive Interface Pin Signal Description Pin Diskette Drive Connector PinoutSerial Interface DB-9 Serial Connector PinoutParallel Interface Support Standard Parallel Port ModeEnhanced Parallel Port Mode Extended Capabilities Port ModePin Signal Function Parallel Interface ConnectorDB-25 Parallel Connector Pinout Keyboard Interface Operation Keyboard/Pointing Device InterfaceData Keyboard/Pointing Device Interface ConnectorKeyboard/Pointing Device Connector Pinout Pointing Device Interface OperationICH10 USB Port Mapping USB ConnectorController Signals USB Connector Location all form factors Universal Serial Bus InterfaceUSB Color Code USB Connector PinoutUSB Cable Data USB Cable Length DataAudio Subsystem Audio Subsystem Functional Block DiagramAudio Multistreaming HD Audio ControllerHD Audio Link Bus ADC/DAC Audio SpecificationsHD Audio Subsystem Specifications Parameter MeasurementLED Network Interface ControllerAlert Standard Format Support Power Management SupportWake-On-LAN Support Parameter Compatibility standard orprotocol NIC ConnectorNIC Specifications NIC SpecificationsIntegrated Graphics Subsystem RGB Functional DescriptionGMA 4500 Memory Allocation Sdram Installed Maximum Memory AllocationIGC Standard 2D Display Modes Resolution Maximum Refresh Rate Analog Digital MonitorDisplay Modes Upgrading DB-15 Monitor Connector Pinout Monitor ConnectorsAnalog Monitor Connector Pin Signal DisplayPort ConnectorIntegrated Graphics Subsystem Usdt Power Distribution Power and Signal DistributionPower Distribution Usdt 135-Watt Power Supply Unit Specifications 2 SFF/CMT Power DistributionMin Range Current Max Surge Tolerance Loading Ripple SFF 240-Watt Power Supply Unit SpecificationsRange or Min Current Max Surge Tolerance Loading Ripple CMT 365-Watt Power Supply Unit SpecificationsEnergy Star Compliancy Shows the power supply cabling for CMT systemsPressed Power Button Results Power ControlPower Button Power Button ActionsPower LED Indications Condition Wake-On-LAN Wake Up EventsConsumption To S0 by Required System Power StatesPower Transition OS Restart State System ConditionCR1 +5 VDC LED Signal DistributionSystem Board Component Designations Power and Signal Distribution System Bios Changeable Splash Screen ROM FlashingUpgrading Memory Detection and Configuration Boot FunctionsBoot Device Order Network Boot F12 SupportVisual power LED Audible speaker Meaning Boot Error CodesBoot Error Codes Client Management Functions INT15 Function ModeClient Management Functions Subsystem Temperature StatusSystem ID and ROM Type System ID NumbersType Data Smbios FunctionsManagement Engine Functions USB Legacy SupportBeeps Power LED Probable Cause Error Messages and CodesBeep/Power LED Codes Table A-1 Beep/Power LED CodesPower-On Self Test Post Messages Table A-2 Table A-2 Error Message Probable CauseTable A-3 System Error Messages Probable Cause System Error MessagesTable A-4 Memory Error Messages Probable Cause Memory Error MessagesTable A-5 Keyboard Error Messages Probable Cause Keyboard Error MessagesTable A-7 Video Graphics Error Messages Probable Cause Printer Error MessagesVideo Graphics Error Messages Table A-6 Printer Error Messages Probable CauseTable A-8 Diskette Drive Error Messages Probable Cause Diskette Drive Error MessagesTable A-9 Serial Interface Error Messages Probable Cause Serial Interface Error MessagesModem Communications Error Messages Table A-11 System Status Error MessagesSystem Status Error Messages Table A-12 Hard Drive Error Messages Probable Cause Hard Drive Error MessagesXx = 03, Hard drive read/write compare test Table A-13 Hard Drive Error Messages Probable Cause Table A-15 Audio Error Messages Probable Cause Audio Error MessagesTable A-14 Video Graphics Error Messages Probable Cause Table A-17 Network Interface Error Messages Probable Cause 17 DVD/CD-ROM Error MessagesNetwork Interface Error Messages DVD/CD-ROM Error MessagesTable A-18 Scsi Interface Error Messages Scsi Interface Error Messages 65xx-xx, 66xx-xxPointing Device Interface Error Messages 8601-xx Error Messages and Codes Numerics IndexIndex
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dc7900 specifications

The HP dc7900 is a well-regarded desktop solution that serves as a testament to HP's commitment to performance, reliability, and user accessibility. Introduced as part of HP’s Compaq line and designed primarily for business professionals, the dc7900 combines powerful processing capabilities with a compact form factor that suits various office environments.

One of the standout features of the HP dc7900 is its robust configuration options. It typically comes equipped with Intel's Core 2 Duo or Quad processors, giving users the ability to handle demanding applications seamlessly. The inclusion of Intel's technologies, such as Intel vPro, enhances remote management and IT control, making it an ideal choice for businesses looking to streamline their operations.

The dc7900 is designed with flexibility in mind. It offers multiple form factors, including mini-tower, small form factor, and ultra-slim desktop configurations. This variety enables organizations to choose a model that best fits their workspace requirements, maximizing both efficiency and aesthetics. The small footprint models are particularly beneficial in space-constrained environments, while the mini-tower version provides expandability for future upgrades.

In terms of graphics capabilities, the HP dc7900 typically features integrated Intel graphics, with options to install discrete graphics cards for users who require enhanced visual performance. This makes the dc7900 suitable for tasks ranging from standard office applications to more graphics-intensive responsibilities.

Connectivity is another key characteristic of the HP dc7900. It is equipped with a variety of ports, including USB 2.0 and audio jacks, allowing users to connect peripherals easily. Additionally, the dc7900 supports legacy connections, making it easier for businesses with older equipment to integrate new systems without hassle.

Durability and reliability are hallmarks of the HP dc7900. Built with high-quality materials and subjected to rigorous testing, this desktop is designed to withstand the demands of a bustling office environment. Furthermore, HP's comprehensive warranty and support options assure businesses of the reliability of their investment.

The HP dc7900 is not just a powerful desktop; it’s a versatile and dependable solution for modern businesses. With its combination of performance, expandability, and solid build quality, the dc7900 remains a relevant choice for those looking to enhance their productivity and efficiency in the workplace.
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