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HP dc7800 tower manual Parallel Interface Support, Standard Parallel Port Mode

Models: dc7800 tower

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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.

 

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HP dc7800 tower manual Parallel Interface Support, Standard Parallel Port Mode, Enhanced Parallel Port Mode
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dc7800 tower specifications

The HP dc7800 Tower is a powerful desktop computer designed for professional and enterprise environments. Known for its stability, performance, and versatility, this model has secured its place in a variety of business settings. Launched in the mid-2000s, it embodies HP’s commitment to quality and innovation.

One of the main features of the HP dc7800 is its form factor. The tower configuration allows for easy upgrades and maintenance, providing ample space for additional hard drives, memory, and other components. This level of accessibility makes it ideal for businesses that need to adapt their systems to changing requirements.

The dc7800 is powered by Intel's Core 2 Duo processors, offering dual-core technology that enhances multitasking capabilities. With clock speeds ranging from 1.8 GHz to 3.0 GHz, this system can handle demanding applications with relative ease. It also supports Intel's vPro technology, which allows for remote management and security features, making it an excellent choice for organizations prioritizing IT control.

Another notable characteristic is the support for up to 8GB of DDR2 RAM. This allows for efficient data processing and improved performance when running multiple applications simultaneously. Additionally, the dc7800 features multiple storage options, accommodating both SATA hard drives and solid-state drives, which can significantly enhance boot times and overall system responsiveness.

Connectivity options on the HP dc7800 are robust. It includes a variety of USB ports, audio jacks, and optional legacy ports, ensuring compatibility with a wide range of peripherals and accessories. Networking capabilities are also prominent, with built-in Gigabit Ethernet providing high-speed internet access.

Furthermore, the desktop tower is designed with energy efficiency in mind. It meets ENERGY STAR certification standards, which not only helps reduce operational costs but also minimizes environmental impact.

Overall, the HP dc7800 Tower embodies a blend of performance, expandability, and energy efficiency, making it a reliable choice for businesses in need of a robust desktop solution. With its legacy of dependability and its suite of modern technologies, it continues to serve as a valuable asset in enterprise environments.