LAN91C94 datasheet(87/120 Pages) SMSC

87 / 120 page

BOARD SETUP INFORMATION

The following parameters are obtained from the

EEPROM as board setup information:

ETHERNET INDIVIDUAL ADDRESS

I/O BASE ADDRESS

ROM BASE ADDRESS

8/16 BIT ADAPTER

10BASE-T or AUI INTERFACE

INTERRUPT LINE SELECTION

All the above mentioned values are read from

the EEPROM upon hardware reset. Except for

the INDIVIDUAL ADDRESS, the value of the

IOS switches determines the offset within the

EEPROM for these parameters, in such a way

that many identical boards can be plugged into

the same system by just changing the IOS

jumpers.

In order to support a software utility based

installation, even if the EEPROM was never

programmed, the EEPROM can be written using

the LAN91C94. One of the IOS combination is

associated with a fixed default value for the key

parameters

(I/O

BASE,

ROM

BASE,

INTERRUPT)

that

can

always

used

regardless of the EEPROM based value being

programmed. This value will be used if all IOS

pins are left open or pulled high.

The EEPROM is arranged as a 64 x 16 array.

The specific target device is the 9346 1024-bit

Serial EEPROM.

All EEPROM accesses are

done in words. All EEPROM addresses shown

are specified as word addresses.

INDIVIDUAL ADDRESS

20-22 hex

If IOS2-0 = 7 , only the INDIVIDUAL ADDRESS

is read from the EEPROM. Currently assigned

values are assumed for the other registers.

These values are default if the EEPROM read

operation follows hardware reset.

The EEPROM SELECT bit is used to determine

the type of EEPROM operation: a) normal or b)

general purpose register.

NORMAL

EEPROM

OPERATION

EEPROM SELECT bit = 0

On EEPROM read operations (after reset or

after

setting

RELOAD

high)

the

CONFIGURATION

and

BASE

values at locations defined by the IOS2-0 pins.

The

INDIVIDUAL

ADDRESS

registers

are

updated

with

the

values

stored

the

INDIVIDUAL ADDRESS area of the EEPROM.

EEPROM WORD

ADDRESS

Configuration

Base Register

IOS Value * 4

(IOS Value *4) + 1

LAN91C94 Datasheet(PDF) 87 Page - SMSC Corporation

LAN91C94 Datasheet(HTML) 87 Page - SMSC Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL