SMC91C100 Datasheet, PDF (21/83 Pages) List of Unclassifed Manufacturers – FEAST Fast Ethernet Controller

BANK SELECT REGISTER
OFFSET
E
NAME
BANK SELECT REGISTER
HIGH BYTE
0
0
1
1
0
0
1
1
TYPE
READ/WRITE
0
0
1
0
0
1
SYMBOL
BSR
1
1
LOW BYTE
BS2
BS1 BS0
X
X
X
X
X
0
0
0
BS2, BS1, BS0 Determine the bank presently in
use. This register is always accessible and is
used to select the register bank in use.
a doubleword write to offset Ch will write the
BANK SELECT REGISTER but will not write the
registers Ch and Dh.
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.
BANK 7 has no internal registers other than the
BANK SELECT REGISTER itself. On valid cycles
where BANK7 is selected (BS0=BS1=BS2=1),
and A3=0, nCSOUT is activated to facilitate
implementation of external registers.
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
Note: BANK7 does not exist in SMC91C9x
devices. For backward S/W compatibility BANK7
accesses should be done if the Revision Control
register indicates the device is SMC91C100.
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