91C94 Datasheet, PDF (42/120 Pages) SMSC Corporation – ISA/PCMCIA SINGLE CHIP ETHERNET CONTROLLER WITH RAM

I/O SPACE - BANK0
OFFSET
NAME
8
MEMORY INFORMATION REGISTER
TYPE
READ ONLY
SYMBOL
MIR
For software compatibility with other LAN9000 parts all memory-related information is represented
in 256 x M byte units, where the multiplier M is determined by the MCR upper byte. M equals 1 for
the LAN91C94.
HIGH
BYTE
FREE MEMORY AVAILABLE (in bytes x 256 x M)
0
0
0
1
0
0
1
0
LOW
BYTE
MEMORY SIZE (in bytes x 256 x M)
0
0
0
1
0
0
1
0
FREE MEMORY AVAILABLE - This register can
be read at any time to determine the amount of
free memory. The register defaults to the
MEMORY SIZE upon reset or upon the RESET
MMU command.
MEMORY SIZE - This register can be read to
determine the total memory size, and will
always read 12H (4608 bytes) for the
LAN91C94.
MEMORY SIZE
REGISTER
M
LAN91C90
FFH
1
LAN91C90
40H
1
LAN91C92/4
12H
1
LAN91C100
FFH
2
ACTUAL
MEMORY
64 Kbytes
16 Kbytes
4608 bytes
128 kbytes
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