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

3.3.1Address Decoding Example

 

 

 

 

BYTE

 

A3

A2

A1

IO-ADDRESS

ENABLE

NOTES

 

 

 

 

 

 

0

0

0

300

nBE0

Assert nBE0 to enable the lowest byte

 

 

 

 

 

 

0

0

0

301

nBE1

Assert nBE1 to enable the second lowest byte

 

 

 

 

 

 

0

0

1

302

nBE0

Assert nBE0 to enable the lowest byte

 

 

 

 

 

 

0

0

1

303

nBE1

Assert nBE1 to enable the second lowest byte

 

 

 

 

 

 

0

1

0

304

nBE0

Assert nBE0 to enable the lowest byte

 

 

 

 

 

 

0

1

0

305

nBE1

Assert nBE1 to enable the second lowest byte

 

 

 

 

 

 

0

1

1

306

nBE0

Assert nBE0 to enable the lowest byte

 

 

 

 

 

 

0

1

1

307

nBE1

Assert nBE1 to enable the second lowest byte

 

 

 

 

 

 

3.3.2I/O Base Address 300h Decoding

 

 

The chart below shows the decoding of

I/O Base Address 300h:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A15

A14

A13

A12

A11

A10

A9

A8

 

A7

A6

A5

 

A4

A3

A2

A1

A0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

0

0

0

0

0

1

1

 

0

0

0

 

0

0

0

0

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3.4Asynchronous Interface

When the LAN91C111 working with an asynchronous bus, the read and write operation are controlled by the edges of nRD and nWR. ARDY is used for notifying the system that it should extend the access cycle. The leading edge of ARDY is generated by the leading edge of nRD or nWR while the trailing edge of ARDY is controlled by the internal LAN91C111 clock and, therefore, asynchronous to the bus.

SMSC AN 9.6

5

Revision 1.0 (08-14-08)

APPLICATION NOTE