SMSC LAN91C111 32/16/8-Bit Three-In-One Fast Ethernet Controller

3 Description Of Bus Interface Unit (BIU)

This section is intended to aid design engineers connecting the SMSC LAN91C111 device to a microprocessor or microcontroller. This section will discuss in detail the functional block, and the individual control signals of the LAN91C111 involved in the connection between the device and an associated microprocessor / microcontroller.

3.1 Pin Function Listing

The LAN91C111 consist of the following major pin groups:

PIN DESCRIPTION

NUMBER OF PINS USED

 

 

System Address Pins

20

 

 

System Data Pins

32

 

 

System Control Pins

14

 

 

Serial EEPROM Pins

8

 

 

LED Pins

2

 

 

PHY Pins

8

 

 

Crystal Oscillator

2

 

 

Power Pins

10

 

 

Ground Pins

12

 

 

MII Connection Pins

18

 

 

Misc. Pins

2

 

 

The interfacing of the LAN91C111 is based on the use of the control lines to control the flow of information to and from the controller. The LAN91C111 is designed with the flexibility required to allow a design engineer to connect the LAN91C111 to just about any standard microprocessor architecture. This document should provide a design engineer the information needed to connect the LAN91C111 to the microprocessor or microcontroller of their choice.

SMSC AN 9.6

3

Revision 1.0 (08-14-08)

APPLICATION NOTE