am79c974 Advanced Micro Devices, am79c974 Datasheet - Page 2

• Manufacturer Part Number: am79c974
• Description: Pcnettm-scsi Combination Ethernet And Scsi Controller For Pci Systems
• Manufacturer: Advanced Micro Devices

The PCnet-SCSI is part of AMD’s PCI product family of
plug-in and software compatible SCSI and Ethernet
controllers. This product compatibility ensures a low
cost system upgrade path and lower motherboard
manufacturing costs.
Ethernet Specific
The PCnet-SCSI controller includes a complete Ether-
net node integrated into a single VLSI device. It contains
a bus interface unit, a DMA buffer management unit, an
IEEE 802.3-defined Media Access Control (MAC) func-
tion, individual 136-byte transmit and 128-byte receive
FIFOs, an IEEE 802.3-defined Attachment Unit Inter-
face (AUI) and Twisted-Pair Transceiver Media Attach-
ment Unit (10BASE-T MAU), and a Microwire EEPROM
interface. The PCnet-SCSI controller is also register
compatible with the LANCE (Am7990) Ethernet control-
ler, the C-LANCE (Am79C90) Ethernet controller, the
ILACC (Am79C900) Ethernet controller, and all Ether-
net controllers in the PCnet Family, including the PCnet-
ISA controller (Am79C960), the PCnet-ISA+ controller
(Am79C961),
(Am79C965). The buffer management unit supports the
LANCE, ILACC, and PCnet descriptor software models.
The PCnet-SCSI controller is software compatible with
the Novell NE2100 and NE1500 Ethernet adapter card
architectures. In addition, a Sleep function has been in-
corporated to provide low standby current, excellent for
notebooks and Green PCs.
The 32-bit multiplexed bus interface unit provides a di-
rect interface to the PCI local bus applications, simplify-
ing the design of an Ethernet node in a PC system. With
its built-in support for both little and big endian byte
alignment, this controller also addresses proprietary
non-PC applications.
The PCnet-SCSI controller supports auto configuration
in the PCI configuration space. Additional PCnet-SCSI
controller configuration parameters, including the
unique IEEE physical address, can be read from an ex-
ternal non-volatile memory (serial EEPROM) immedi-
ately following system RESET.
The controller also has the capability to automatically
select either the AUI port or the Twisted-Pair trans-
ceiver. Only one interface is active at any one time. The
individual transmit and receive FIFOs optimize system
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AMD
and
the
PCnet-32
controller
P R E L I M I N A R Y
Am79C974
overhead, providing sufficient latency during frame
transmission and reception, and minimizing intervention
during normal network error recovery. The integrated
Manchester encoder/decoder (MENDEC) eliminates
the need for an external Serial Interface Adapter (SIA) in
the system. In addition, the device provides program-
mable on-chip LED drivers for transmit, receive, colli-
sion, receive polarity, link integrity or jabber status.
SCSI Specific
The PCnet-SCSI controller also includes a high-
performance Fast SCSI controller with a glueless inter-
face to the PCI local bus. The PCnet-SCSI integrates its
own 32-bit bus mastering DMA engine with an industry
standard Fast SCSI-2 block. The DMA engine and ac-
companying 96 byte DMA FIFO allow 32-bit burst data
transfers across the high bandwidth PCI bus at speeds
of up to 132 Mbyte/s. Full support for scatter-gather
DMA transfers optimize performance in multi-tasking
system applications.
The PCnet-SCSI’s on-chip state machine controls SCSI
bus sequences in hardware and is coupled with the bus
mastering DMA engine to eliminate the need for an on-
chip RISC processor. This results in a smaller die size
giving the Am79C974 superior price/performance ver-
sus competitive offerings.
AMD supports the Am79C974 with a total system solu-
tion which includes:
For more detailed information on the PCnet-SCSI refer
to the technical manual, PID #18738A.
A full suite of licensable SCSI drivers and utilities
fully tested under the following operating system
environments:
— DOS 5.0 – 6.0
— Windows 3.1
— Windows NT
— OS/2 2.x
— Netware 3.x, 4.x
— SCO UNIX 3.2.4, ODT 2.0
An INT13h Compatible SCSI ROM BIOS
ASPI Compatibility
Complete hardware reference design kit