82595FX Datasheet, PDF (33/54 Pages) Intel Corporation – ISA BUS HIGH INTEGRATION ETHERNET CONTROLLER

82595FX
 Complies with IEEE 802 3 AUI Standard
Direct Interface to AUI Transformers
On-Chip AUI Squelch
 Complies with IEEE 802 3 10BASE-T for
Twisted Pair Ethernet
Selectable Polarity Detection and
Correction
Direct Interface to TPE Analog Filters
On-Chip TPE Squelch
Defeatable Link Integrity for Pre-Standard
Networks
Supports 4 LEDs (Link Integrity Activity
AUI BNC DIS and Polarity Correction)
Auto-Negotiation of Full Duplex
Functionality
10 0 APPLICATION NOTES
This section is intended to provide Ethernet LAN de-
signers with a basic understanding of how the
82595FX is used in a buffered LAN design
10 1 Bus Interface
The 82595FX Bus Interface unit integrates ISA Bus
data transceivers providing an even more cost effi-
cient and seamless integration than that of the
82595TX The 82595FX provides the complete con-
trol and address interface to the host system bus
implementing a complete ISA bus protocol
10 2 Local Memory Interface
The 82595FX’s local memory interface includes a
DMA unit which controls data transfers between the
82595FX and the local memory SRAM The
82595FX can support up to 64 Kbytes of local
SRAM
The 82595FX provides address decoding and con-
trol to allow access to an external Boot EPROM or a
FLASH Addition of a Boot EPROM or FLASH to an
ISA solution is optional The IA is assumed to be
stored in the serial EEPROM for the ISA solution
10 3 EEPROM Interface
The 82595FX provides a complete interface to a se-
rial EEPROM for ISA adapter designs For ISA moth-
erboard designs the EEPROM is not required The
EEPROM is used to store configuration information
such as Memory and IO Mapping Window Interrupt
line selection Plug N’ Play resource data local bus
width etc The EEPROM is used to replace jumper
blocks which previously contained this type of infor-
mation
10 4 Serial Interface
The 82595FX’s serial interface provides either an
AUI port interface or a Twisted Pair Ethernet (TPE)
interface The AUI port can be connected to an
Ethernet Transceiver cable drop to provide a fully
compliant IEEE 802 3 10BASE5 interface The AUI
port can also be interfaced to a transceiver device
on the adapter to provide a fully compliant IEEE
802 3 10BASE2 (Cheapernet) interface The TPE
port provides a fully compliant 10BASE-T interface
The 82595FX automatically enables either the AUI
or TPE interface depending on which medium is
connected to the chip This automatic selection can
be overridden by software configuration
10 4 1 AUI CIRCUIT
When used in conjunction with pulse transformers
the 82595FX provides a complete IEEE 802 3 AUI
interface In order to meet the 16V fault tolerance
specification of IEEE 802 3 a pulse transformer is
recommended The transformer should be placed
between the TRMT RCV and CLSN pairs of the
82595FX and the DO DI and CI pairs of the AUI
(DB-15) connector The pulse transformer should
have the following characteristics
 75 mH minimum inductance (100 mH recom-
mended)
 2000V isolation between the primary and second-
ary windings
 2000V isolation between the primaries of sepa-
rate transformers
 1 1 Turns ratio
The RCV and CLSN input pairs should each be ter-
minated by 78 7X g1% resistors
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