AGP
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AGP

AGP [Accelerated Graphics port] is a Point-to-Point [Chip-to-Chip] bus using 1.5 Volt or 3.3V signaling. The main use of the AGP bus is as a Local Video bus in IBM compatible Personal Computers [PCs]

 132 pin EDGE (AGP bus)
132 pin EDGE (AGP bus) connector  at the computer motherboard

The Accelerated Graphics Port (also called Advanced Graphics Port) is a high-speed point-to-point channel for attaching a single device (generally a graphics card) to a computer"s motherboard, primarily to assist in the acceleration of 3D computer graphics. Many classify AGP as a type of computer bus, but this is something of a misnomer since buses generally allow multiple devices to be connected, while AGP does not. Some motherboards have been built with multiple independent AGP slots.

AGP dynamically allocates the PC"s normal RAM to store the screen image and to support some features. RAM used in this manner is referred to as the AGP Aperture. AGP originated from Intel, and it was first built into a chipset for the Pentium II microprocessor in 1997. AGP cards generally slightly exceed PCI cards in length and can be recognized by a typical "hook" at the inner end of the connector, which does not exist on PCI cards.

AGP versions includes:

  • AGP 1x (AGP 1.0), uses a 32-bit channel operating at 66 MHz with 1.5 V or 3.3 V signaling. This results in a maximum data rate for an AGP 1x slot of 266 megabytes per second. In comparison, a standard 32-bit 33 MHz PCI bus (which can be composed of one or more slots) is limited to 133 MB/s.
  • AGP 2x, using a 32-bit channel operating at 66 MHz double pumped to an effective 133 MHz resulting in a maximum data rate of 533 megabytes per second; signaling voltages the same as AGP 1x;
  • AGP 4x, using a 32-bit channel operating at 133 MHz double pumped to an effective 266 MHz resulting in a maximum data rate of 1066 megabytes per second; 1.5 V signaling;
  • AGP 8x, double pumped at 266 MHz to give a maximum of 2133 megabytes per second; 0.8 V signaling.
  • In addition, AGP Pro cards of various types exist. They require more power and are often longer than standard AGP card (though they only connect to one AGP slot). These cards are usually used to accelerate the professional computer-aided design applications employed in the fields of architecture, machining, engineering, and similar fields.

    Pin Name
    A1+12 V dc
    A2spare
    A3Reserved* Ground
    A4USB-
    A5Ground
    A6INTA#
    A7RST#
    A8GNT#
    A9VCC 3.3
    A10ST1
    A11Reserved
    A12PIPE#
    A13Ground
    A14Spare
    A15SBA1
    A16VCC 3.3
    A17SBA3
    A18Reserved
    A19Ground
    A20SBA5
    A21SBA7
    A22Key
    A23Key
    A24Key
    A25Key
    A26AD30
    A27AD28
    A28VCC 3.3
    A29AD26
    A30AD24
    A31Ground
    A32Reserved
    A33C/BE3#
    A34Vddq 3.3
    A35AD22
    A36AD20
    A37Ground
    A38AD18
    A39AD16
    A40Vddq 3.3
    A41FRAME#
    A42Spare
    A43Ground
    A44Spare
    A45VCC 3.3
    A46TRDY#
    A47STOP#
    A48Spare
    A49Ground
    A50PAR
    A51AD15
    A52Vddq 3.3
    A53AD13
    A54AD11
    A55Ground
    A56AD9
    A57C/BE0#
    A58Vddq 3.3
    A59Reserved
    A60AD6
    A61Ground
    A62AD4
    A63AD2
    A64Vddq 3.3
    A65AD0
    A66SMB1
    B1spare
    B2+5 V dc
    B3+5 V dc
    B4USB+
    B5Ground
    B6INTB#
    B7CLK
    B8REQ#
    B9VCC 3.3
    B10ST0
    B11ST2
    B12RBF#
    B13Ground
    B14Spare
    B15SBA0
    B16VCC 3.3
    B17SBA2
    B18SB_STB
    B19Ground
    B20SBA4
    B21SBA6
    B22Key
    B23Key
    B24Key
    B25Key
    B26AD31
    B27AD29
    B28VCC 3.3
    B29AD27
    B30AD25
    B31Ground
    B32AD STB1
    B33AD23
    B34Vddq 3.3
    B35AD21
    B36AD19
    B37Ground
    B38AD17
    B39C/BE2#
    B40Vddq 3.3
    B41IRDY#
    B42Spare
    B43Ground
    B44Spare
    B45VCC 3.3
    B46DEVSEL#
    B47Vddq 3.3
    B48PERR#
    B49Ground
    B50SERR#
    B51C/BE1#
    B52Vddq 3.3
    B53AD14
    B54AD12
    B55Ground
    B56AD10
    B57AD8
    B58Vddq 3.3
    B59AD STB0
    B60AD7
    B61Ground
    B62AD5
    B63AD3
    B64Vddq 3.3
    B65AD1
    B66SMB0

    The AGP bus is 32 bits wide, just the same as PCI is, but instead of running at half of the system (memory) bus speed the way PCI does, it runs at full bus speed. This means that on a standard Pentium II motherboard AGP runs at 66 MHz instead of the PCI bus"s 33 MHz. This of course immediately doubles the bandwidth of the port; instead of the limit of 127.2 MB/s as with PCI, AGP in its lowest speed mode has a bandwidth of 254.3 MB/s. The AGP specification is in fact based on the PCI 2.1 specification, which includes a high-bandwidth 66 MHz speed that was never implemented on the PC.

    This reserved pin should be connected to Ground

    Source:www.pinouts.ru


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