am79c961a Advanced Micro Devices, am79c961a Datasheet - Page 2

• Manufacturer Part Number: am79c961a
• Description: Pcnet?-isa Ii Jumperless, Full Duplex Single-chip Ethernet Controller For Isa
• Manufacturer: Advanced Micro Devices

GENERAL DESCRIPTION
The PCnet-ISA II controller, a single-chip Ethernet con-
troller, is a highly integrated system solution for the
PC-AT Industry Standard Architecture (ISA) architec-
ture. It is designed to provide flexibility and compatibil-
ity with any existing PC application. This highly
integrated VLSI device is specifically designed to re-
duce parts count and cost, and addresses applications
where higher system throughput is desired. The PC-
net-ISA II controller is fabricated with AMD’s advanced
low-power CMOS process to provide low standby cur-
rent for power sensitive applications.
The PCnet-ISA II controller can be configured into one
of three different architecture modes to suit a particular
PC application. In the Bus Master mode, all transfers
are performed using the integrated DMA controller.
This configuration enhances system performance by
allowing the PCnet-ISA II controller to bypass the plat-
form DMA controller and directly address the full 24-bit
memory space. The implementation of Bus Master
mode allows minimum parts count for the majority of
PC applications. The PCnet-ISA II can also be config-
ured as a Bus Slave with either a Shared Memory or
Programmed I/O architecture for compatibility with
low-end machines, such as PC/XTs that do not support
Bus Masters, and high-end machines that require local
packet buffering for increased system latency.
The PCnet-ISA II controller is designed to directly inter-
face with the ISA or EISA system bus. It contains an
ISA Plug and Play bus interface unit, DMA Buffer Man-
agement Unit, 802.3 Media Access Control function,
individual 136-byte transmit and 128-byte receive
FIFOs, IEEE 802.3 defined Attachment Unit Interface
(AUI), and a Twisted Pair Transceiver Media Attach-
ment Unit. Full duplex network operation can be
enabled on any of the device’s network ports. The PC-
net-ISA II controller is also register compatible with the
LANCE (Am7990) Ethernet controller and PCnet-ISA
(Am79C960). The DMA Buffer Management Unit sup-
ports the LANCE descriptor software model. External
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Am79C961A
remote boot and Ethernet physical address PROMs
and Electrically Erasable Proms are also supported.
This advanced Ethernet controller has the built-in
capability of automatically selecting either the AUI port
or the Twisted Pair transceiver. Only one interface is
active at any one time. The individual 136-byte transmit
and 128-byte receive FIFOs optimize system over-
head, providing sufficient latency during packet trans-
mission and reception, and minimizing intervention
during normal network error recovery. The integrated
Manchester encoder/decoder eliminates the need for
an external Serial Interface Adapter (SIA) in the node
system. If support for an external encoding/decoding
scheme is desired, the embedded General Purpose
Serial Interface (GPSI) allows direct access to/from the
MAC. In addition, the device provides programmable
on-chip LED drivers for transmit, receive, collision,
receive polarity, link integrity and activity, or jabber
status. The PCnet-ISA II controller also provides an
External Address Detection Interface
allow external hardware address filtering in internet-
working applications.
For power sensitive applications where low stand-by
current is desired, the device incorporates a sleep
function to reduce over-all system power consumption,
excellent for notebooks and Green PCs. In conjunction
with this low power mode, the PCnet-ISA II controller
also has integrated functions to support Magic Packet,
an inexpensive technology that allows remote wake up
of Green PCs.
With the rise of embedded networking applications
operating in harsh environments where temperatures
may exceed the normal commercial temperature (0 C
to +70 C) window, an industrial temperature (–40 C to
+85 C) version is available in all two packages; 132-pin
PQFP and 144-pin TQFP. The industrial temperature
version of the PCnet-ISA II Ethernet controller is
characterized across the industrial temperature range
(–40 C to +85 C) within the published power supply
specification (4.75 V to 5.25 V; i.e., 5% V
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