SMC Networks SMC91C95 - Manual (Page 89)

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802Ah - Modem I/O BASE Register 0
7 6 5 4 3 2 1 0
A7 A6 A5 A4 A3 0 0 0
0 0 0 0 0 0 0 0
802Ch - Modem I/O BASE Register 1
7 6 5 4 3 2 1 0
A15 A14 A13 A12 A11 A10 A9 A8
0 0 0 0 0 0 1 1
The Modem I/O Base registers determine the
base address of the I/O range used to access
function specific registers. These registers allow
the function's registers to be placed anywhere in
the host's I/O space. I/O Base 0 contains the
low order byte (A7-A0) and I/O Base 1 contains
the high order byte (A15-A8). Since the modem
function requires 8 I/O locations, bits 2-0 of I/O Base 0 are always 0. Since only A15 to A4 are
decoded by the controller (64K address space),
it is up to the host to resolve any conflicts with
addressing above 64K.
These registers are still accessable even if the
“Enable Base and Limit” bit in the MCOR is
cleared (0).