Asus PCI-SC896 User Manual - Page 11

Introduction, 3 Interface Descriptions

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1. Introduction 1. Introduction 1.3 Interface Descriptions This section provides a more detailed explanation about the PCI Interface, the SCSI Interface, the SCSI Activity LED Interface, and Wide Ultra2 SCSI. 1.3.1 The PCI Interface PCI is a high-speed standard local bus for interfacing a number of I/O components to a PC processor and memory subsystem. The PCI functionality for the PCI-SC896 is contained within the ASUS PCI-SC896 PCI-SCSI I/O Processor chip. The PCI-SC896 connects directly to the PCI bus and generates timing protocol in compliance with the PCI specification. The PCI interface operates as a 32-bit DMA bus master. The connection is made through the edge connector J1. The signal definitions and pin numbers conform to the PCI Local Bus Specification Revision 2.1 standard. The PCI-SC896 conforms to the PCI universal signaling environment for a 5 V or 3.3 V PCI bus. 1.3.2 The SCSI Interface The SCSI functionality for the PCI-SC896 is contained within the ASUS PCISC896 PCI-SCSI I/O Processor chip. The PCI-SC896 connects directly to the two SCSI buses for SE or LVD SCSI applications and generates timing and protocol in compliance with the SCSI standard. Each SCSI interface operates at a burst transfer rate of up to 40 Mbyte per second for wide single-ended transfers, and up to 80 Mbyte per second for wide LVD SCSI transfers. The SCSI interfaces on the PCI-SC896 operates as two 16-bit, synchronous or asynchronous, single-ended or LVD, and supports Ultra2 SCSI protocols and 16-bit arbitration. The PCI-SC896 board provides autosensing, dual mode SE/ LVD SCSI termination. Termination is normally enabled. When a SCSI device is sensed to be connected to both internal and external connectors, termination for that channel is automatically disabled. The PCI-SC896 supplies SCSI bus TERMPWR (termination power) through a blocking diode and self-resetting 1.5 A short circuit protection device. An on-board LED lights up when TERMPWR is shorted and turns off. A 40 MHz oscillator is installed on the PCI-SC896 board to provide the clock frequency to the PCI-SC896 that is necessary to support Wide Ultra2 SCSI transfers of up to 80 Mbytes/s. ASUS PCI-SC896 User's Manual 11

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ASUS PCI-SC896 User’s Manual
11
1. Introduction
1. Introduction
1.3 Interface Descriptions
This section provides a more detailed explanation about the PCI Interface, the
SCSI Interface, the SCSI Activity LED Interface, and Wide Ultra2 SCSI.
1.3.1 The PCI Interface
PCI is a high-speed standard local bus for interfacing a number of I/O compo-
nents to a PC processor and memory subsystem. The PCI functionality for the
PCI-SC896 is contained within the ASUS PCI-SC896 PCI-SCSI I/O Processor
chip. The PCI-SC896 connects directly to the PCI bus and generates timing
protocol in compliance with the PCI specification. The PCI interface operates as
a 32-bit DMA bus master. The connection is made through the edge connector
J1. The signal definitions and pin numbers conform to the PCI Local Bus Speci-
fication Revision 2.1 standard. The PCI-SC896 conforms to the PCI universal
signaling environment for a 5 V or 3.3 V PCI bus.
1.3.2 The SCSI Interface
The SCSI functionality for the PCI-SC896 is contained within the ASUS PCI-
SC896 PCI-SCSI I/O Processor chip. The PCI-SC896 connects directly to the
two SCSI buses for SE or LVD SCSI applications and generates timing and
protocol in compliance with the SCSI standard. Each SCSI interface operates
at a burst transfer rate of up to 40 Mbyte per second for wide single-ended
transfers, and up to 80 Mbyte per second for wide LVD SCSI transfers.
The SCSI interfaces on the PCI-SC896 operates as two 16-bit, synchronous or
asynchronous, single-ended or LVD, and supports Ultra2 SCSI protocols and
16-bit arbitration. The PCI-SC896 board provides autosensing, dual mode SE/
LVD SCSI termination. Termination is normally enabled. When a SCSI device
is sensed to be connected to both internal and external connectors, termination
for that channel is automatically disabled. The PCI-SC896 supplies SCSI bus
TERMPWR (termination power) through a blocking diode and self-resetting
1.5 A short circuit protection device. An on-board LED lights up when
TERMPWR is shorted and turns off. A 40 MHz oscillator is installed on the
PCI-SC896 board to provide the clock frequency to the PCI-SC896 that is
necessary to support Wide Ultra2 SCSI transfers of up to 80 Mbytes/s.