Introduction to ISA, PCI, AGP, And USB Interface Standards || Basic I/O Interfacing || Bcis Notes

Introduction to ISA, PCI, AGP, And USB Interface Standards

Introduction to ISA, PCI, AGP, And USB Interface Standards can explain below.

Introduction to ISA

Short for Industry Standard Architecture, ISA was introduced by IBM and headed by Mark Dean. ISA was originally an 8-bit computer bus that was later expanded to a 16-bit bus in 1984. When this bus was originally released, it was a proprietary bus, which allowed only IBM to create peripherals and the actual interface. However, in the early 1980s, other manufacturers were creating the bus. In 1993, Intel and Microsoft introduced a PnP ISA bus that allowed the computer to automatically detect and setup computer ISA peripherals, such as a modem or sound card. Using the PnP technology, an end-user would have the capability of connecting a device and not having to configure the device using jumpers or dip switches. All modern computers no longer have ISA slots and instead utilizing PCI slots. Below is an example of an ISA expansion card and ISA slot it connects into on the motherboard.

Introduction to PCI

PCI, Stands for “Peripheral Component Interconnect.” PCI is a hardware bus used for adding internal components to a desktop computer. For example, a PCI card can be inserted into a PCI slot on a motherboard, providing additional I/O ports on the back of a computer.

Introduction to AGP

Short for accelerated graphics port, AGP is an advanced port designed for video cards and 3D accelerators. Developed by Intel and introduced in August 1997, AGP introduces a dedicated point-to-point channel that allows the graphics controller direct access to the system memory. Below is an illustration of what the AGP slot may look like on your motherboard.

Introduction to AGP

Accelerated graphics port, AGP is an advanced port designed for video cards and 3D accelerators. Developed by Intel and introduced in August 1997, AGP introduces a dedicated point-to-point channel that allows the graphics controller direct access to the system memory. Below is an illustration of what the AGP slot may look like on your motherboard. The AGP channel is 32-bits wide and runs at 66 MHz, which is a total bandwidth of 266 MBps and much greater than the PCI bandwidth of up to 133 MBps. AGP also supports two optional faster modes, with a throughput of 533 MBps and 1.07 GBps. It also allows 3-D textures to be stored in the main memory rather than video memory. AGP is available in three different versions, the original AGP version mentioned above, AGP 2.0 that was introduced in May 1998, and AGP 3.0 (AGP 8x) that was introduced in November 2000. AGP 2.0 added 4x signaling and was capable of operating at 1.5V, and AGP 3.0 was capable of double the transfer speeds.

Introduction to USB

USB is an interface that connects a device to a computer. With this connection, the computer sends or retrieves data
from the device. USB gives developers a standard interface to use in many different types of applications. A USB
device is easy to connect and use because of a systematic design process. This application note is intended to help
make that process simpler.

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