91C94 Datasheet, PDF (31/120 Pages) SMSC Corporation – ISA/PCMCIA SINGLE CHIP ETHERNET CONTROLLER WITH RAM

ATTRIBUTE MEMORY SPACE
(PCMCIA mode only)
with the following control signals: nREG, nCE1,
nWE, nOE.
In PCMCIA mode, the attribute memory space is
an eight bit space decoded by the LAN91C94
using addresses A0-9, A15 along
The LAN91C94 has the following two registers
in memory space:
OFFSET
NAME
TYPE
SYMBOL
8000
CARD OPTION REGISTER
READ/WRITE
COR
This register is used to enable the PCMCIA card, allow programming of the external attribute memory,
and to generate soft reset.
SRESET LEVIRQ
0
0
0
COR2
0
COR0
(read only)
0
1
0
0
0
0
0
0
SRESET - This bit, when set will reset the
LAN91C94. It is valid in PCMCIA mode only.
The bit does not sample the ISA/PCMCIA mode.
The bit is cleared writing it low or by a hardware
reset. It does not preserve any register. It
resembles a hardware reset, including the
PWRDWN gating.
LEVIRQ - This bit reads always high to indicate
that the LAN91C94 uses level mode interrupts.
COR2 - This bit, when set, allows writing into
the external attribute memory.
COR0 - This bit, when clear, disables the
LAN91C94 I/O space and forces nIREQ
inactive. This bit defaults low and will be set by
the host PCMCIA system to configure the card
for I/O operation.
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