LAN91C100FD datasheet(56/79 Pages) SMSC

56 / 79 page

FEAST Fast Ethernet Controller with Full Duplex Capability

Rev. 10/14/2002

Page 56

SMSC DS – LAN91C100FD Rev. D

PRELIMINARY

Chapter 7 Application Considerations

The LAN91C100FD is envisioned to fit a few different bus types. This section describes the basic

guidelines, system level implications and sample configurations for the most relevant bus types. All

applications are based on buffered architectures with a private SRAM bus.

7.1

Fast Ethernet Slave Adapter

Slave non-intelligent board implementing 100 Mbps and 10 Mbps speeds.

Adapter requires:

a) LAN91C100FD chip

b) Four SRAMs (32k x 8 - 25ns)

Serial EEPROM (93C46)

d) Mbps ENDEC and transceiver chip

e) Mbps MII compliant PHY

Some bus specific glue logic

Target systems:

a) VL Local Bus 32 bit systems

b) High-end ISA or non-burst EISA machines

EISA 32 bit slave

7.2

VL Local Bus 32 Bit Systems

On VL Local Bus and other 32 bit embedded systems the LAN91C100FD is accessed as a 32 bit

peripheral in terms of the bus interface. All registers except the DATA REGISTER will be accessed using

byte or word instructions. Accesses to the DATA REGISTER could use byte, word, or dword instructions.

Table 7.1 - VL Local Bus Signal Connections

VL BUS

SIGNAL

LAN91C100

SIGNAL

NOTES

A2-A15

Address bus used for I/O space and register decoding, latched

by nADS rising edge, and transparent on nADS low time.

M/nIO

AEN

Qualifies valid I/O decoding - enabled access when low. This

signal is latched by nADS rising edge and transparent on nADS

low time.

W/nR

Direction of access. Sampled by the LAN91C100FD on first

rising clock that has nCYCLE active. High on writes, low on

reads.

nRDYRTN

Ready return. Direct connection to VL bus.

nLRDY

nSRDY and

some logic

nSRDY has the appropriate functionality and timing to create the

VL nLRDY except that nLRDY behaves like an open drain output

most of the time.

LCLK

Local Bus Clock. Rising edges used for synchronous bus

interface transactions.

nRESET

RESET

Connected via inverter to the LAN91C100FD.

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