LSI SYM8953U - Manual (Page 14)

3.75 pc 10.25 pc 11.25 pc 38.25 pc
4.333 pc
48.583 pc
52.5 pc
34.5 pc
44.25 pc
1-4 Using the SYM8953U Host Adapter
1.3.1 The PCI Interface
PCI, a high-speed standard local bus, interfaces I/O components to the
processor and memory subsystems in equipment ranging from PCs to
servers. The PCI functionality for the SYM8953U is contained within the
Symbios SYM53C895A PCI to Ultra2 Controller with LVD Link Universal
Transceivers. The SYM53C895A connects directly to the PCI bus and
generates signal timing and bus protocol in compliance with the PCI
Specification Revision 2.2.
The PCI interface operates as a 32-bit DMA bus master capable of
64-bit addressing. The connection is made through edge connector J1,
shown in
Figure 2.1 . The signal definitions and pin numbers conform to
the PCI Local Bus Specification Revision 2.2 standard. The SYM8953U
host adapter 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 SYM8953U is contained within the
SYM53C895A. This chip is a PCI to Ultra2 SCSI Controller with LVD Link
Universal Transceivers. It connects directly to the SCSI bus and
generates signal timing and bus protocol in compliance with SCSI
standards.
The SCSI interface on the SYM8953U operates as an 8-bit or 16-bit
interface. It supports 8-bit or 16-bit, synchronous and asynchronous, LVD
or SE, Fast, Ultra and Ultra2 SCSI protocols in various combinations. The
interface is made through connectors J2 and J3 (see
Figure 2.1 ). Internal
connector J2 is a 68-pin HD right angle latching connector. External
connector J3 is a shielded 68-pin HD right angle connector exposed in
the back panel bracket. An on-board LED (labeled Activity) indicates
SCSI bus activity. LVD/SE dual mode, active termination is provided on
the SYM8953U board. Termination is automatically disabled when both
SCSI connectors are used. The SYM8953U supplies SCSI bus
TERMPWR through a blocking diode and a self-resetting 1.5 A short
circuit protection device. A 40 MHz oscillator is installed on the
SYM8953U to provide the clock frequency to the SYM53C895A that is
necessary to support Ultra2 SCSI transfers of up to 80 Mbytes/s.