82595FX Datasheet, PDF (5/54 Pages) Intel Corporation – ISA BUS HIGH INTEGRATION ETHERNET CONTROLLER

82595FX
1 0 INTRODUCTION
1 1 82595FX Overview
The 82595FX is a highly integrated high perform-
ance LAN controller which provides a cost effective
LAN solution for ISA compatible Personal Computer
(PC) motherboards (both desktop and portable) and
add-on ISA adapter boards The 82595FX integrates
all of the major functions of a buffered LAN solution
into one chip with the exception of the local buffer
memory which is implemented by adding one SRAM
component to the LAN solution The 82595FX’s
Concurrent Processing feature significantly enhanc-
es throughput performance Both system bus and
serial link activities occur concurrently allowing the
82595FX to maximize network bandwidth by mini-
mizing delays associated with transmit or receiving
frames The 82595FX’s bus interface is a glueless
attachment to an ISA bus Its serial interface pro-
vides a Twisted Pair Ethernet (TPE) and an Attach-
ment Unit Interface (AUI) connection By integrating
the majority of the LAN solution functions into one
cost effective component production cost saving
can be achieved as well as significantly decreasing
the design time for a solution This level of integra-
tion also allows an 82595FX solution to be ported
between different applications (PC motherboards
and adapters while maintaining a compatible hard-
ware and software base
The 82595FX’s software interface is optimized to re-
duce the number of processing steps that are re-
quired to interface to the 82595FX solution The
82595FX’s initialization and control registers are di-
rectly addressable within one 16-byte IO address
block The 82595FX can automatically resolve any
conflicts to an IO block by moving its IO offset to an
unused location in the case that a conflict occurs
The 82595FX’s local memory is arranged in a simple
ring buffer structure for efficient transfer of transmit
and receive packets The local memory up to
64 Kbytes of SRAM resides as either a 16-bit or 32-
bit IO port in the host systems IO map programma-
ble through configuration The 82595FX provides di-
rect control over the local SRAM The 82595FX per-
forms a prefetch to the SRAM memory allowing CPU
IO cycles to this data with no added wait-states The
82595FX also provides an interface to up to 1 Mbyte
of FLASH or EPROM memory An interface to an
EEPROM which holds solution configuration values
and can also contain the Node ID allows for the
implementation of a ‘‘jumperless’’ design In addi-
tion the 82595FX contains full hardware support for
the implementation of the ISA Plug N’ Play specifica-
tion Plug N’ Play eliminates jumpers and complicat-
ed setup utilities by allowing peripheral functions to
be added to a PC automatically (such as adapter
cards) without the need to individually configure
each parameter (e g Interrupt IO Address etc)
This allows for configuration ease-of-use which re-
sults in minimal time associated with installation
The 82595FX’s packaging and power management
features are designed to consume minimal board
real estate and system power This is required for
applications such as portable PC motherboard de-
signs which require a solution with very low real es-
tate and power consumption The 82595FX package
is a 160-lead PQFP (Plastic Quad Flat Pack) Its di-
mensions are 28 mm by 28 mm and 3 5 mm in
height The 82595FX contains two power down
modes an SL compatible power down mode which
utilizes the SL SMOUT input and a POWER DOWN
command for non-SL systems
1 2 Power Management
Power management and low power consumption are
two items that will allow any design using the
82595FX to be suitable for green PC use Low pow-
er operation is initiated when software issues a
SLEEP command to the device After a short wait it
will shut off the system clock some parts of the
Backoff Randomizer several input buffers and the
two LED drivers The 82595FX will subsequently
wake up from sleep mode when software initiates an
ISA cycle in the application as well as when it re-
ceives a frame addressed to it The total power con-
sumption when in sleep mode can be as low as ap-
proximately 175 mW Normal idle power consump-
tion is 300 mW
The software POWER DOWN command along with
its companion hardware implementation the
SMOUT I O pin provide additional power manage-
ment capabilities This feature allows the 82595FX
to be powered down and then at some time in the
future be selectively reset without having lost the
current configuration See the 82595FX User’s
Guide for further details on these features
1 3 Auto-Negotiation
Auto-negotiation functionality is a method of auto-
matically determining the highest common operating
mode (i e 10BaseT half duplex 10BaseT full du-
plex etc ) between two network devices Using this
functionality two stations each having a varying
number of different operating modes negotiate the
highest possible common operating mode between
them During the power up sequence the auto-ne-
gotiation functionality will automatically establish a
link with which it can take advantage of any auto-ne-
gotiation-capable device it is connected to An auto-
negotiation capable hub can detect and automatical-
ly configure its ports to take maximum advantage of
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