I/O SPACE - BANK1
OFFSET
NAME
TYPE
SYMBOL
CR
0
CONFIGURATION REGISTER
READ/WRITE
The Configuration Register holds bits that define the adapter configuration and are not expected to
change during run-time. This register is part of the EEPROM-saved setup.
HIGH
BYTE
MII
SELECT
NO WAIT
0
FULL
STEP
AUI
SELECT
1
X
X
X
0
0
0
LOW
BYTE
1
1
0
0
RESERVED
1
INT SEL1 INT SEL0
1
0
0
0
X
MII SELECT
Used to select the network
AUI SELECT This bit is a general purpose
output port. Its value drives pin AUISEL and it
is typically connected to MODE1 pin of the
LAN83C694C. It can be used to select AUI vs.
10BASE-T, or as a general purpose non-volatile
configuration pin. Defaults low.
interface port. When set, the LAN91C100 will
use its MII port and interface a PHY device at
the nibble rate. When clear, the LAN91C100
will use its 10 Mbps ENDEC interface. This bit
drives the MII SEL pin. Switching between ports
should be done with transmitter and receiver
disabled and no transmit/receive packets in
progress.
INT SEL1-0 Used to select one out of four
interrupt pins. The three unused interrupts are
tristated.
NO WAIT
When set, does not request
additional wait states. An exception to this are
accesses to the Data Register if not ready for a
transfer. When clear, negates IOCHRDY for
two to three clocks on any cycle to the
LAN91C100.
INT SEL1
INT SEL0
PIN USED
INTR0
0
0
1
1
0
1
0
1
INTR1
INTR2
INTR3
FULL STEP This bit is a general purpose output
port. Its inverse value drives pin nFSTEP and it
is typically connected to SEL pin of the
LAN83C694C. It can be used to select the
signaling mode for the AUI, or as a general
purpose non-volatile configuration pin. Defaults
low.
30
SMSC [ SMSC CORPORATION ]
