lan91c100 Standard Microsystems Corp., lan91c100 Datasheet - Page 22

• Manufacturer Part Number: lan91c100
• Description: Feast ? Ast Ethernet Controller
• Manufacturer: Standard Microsystems Corp.

BANK SELECT REGISTER
BS2, BS1, BS0 Determine the bank presently in
use. This register is always accessible and is
used to select the register bank in use.
The upper byte always reads as 33h and can be
used to help determine the I/O location of
FEAST.
The BANK SELECT REGISTER is always
accessible regardless of the value of BS0-2.
Note that the bank select register can be
accessed as a doubleword at offset Ch, as a
word at offset Eh, or as at offset Fh, however
BYTE
BYTE
HIGH
LOW
OFFSET
E
0
0
X
BANK SELECT REGISTER
X
0
0
NAME
1
1
X
22
X
1
1
a doubleword write to offset Ch will write the
BANK SELECT REGISTER but will not write the
registers Ch and Dh.
BANK 7 has no internal registers other than the
BANK SELECT REGISTER itself.
cycles
(BS0=BS1=BS2=1), and A3=0, nCSOUT is
activated to facilitate implementation of external
registers.
Note: BANK7 does not exist in LAN91C9x
devices.
BANK7 accesses should be done if the Revision
Control
LAN91C100.
X
0
0
register
For
where
READ/WRITE
TYPE
backward
BS2
0
0
0
indicates
BANK7
S/W
BS1
1
1
0
the
is
SYMBOL
compatibility
BSR
device
On valid
selected
BS0
1
1
0
is