Technical information

4-14
AIC-6915 Ethernet LAN Controller Programmer’s Manual
Illegal Behavior
As a target, when the AIC-6915 accepts a cycle (I/O, memory, configuration) which is
addressed to it and drives
DEVSEL_, it checks the legality of the transaction and aborts
under any of the following conditions:
■
The combination of CBE[3:0]_ in an I/O cycle does not match the address. The
AIC-6915 aborts the cycle and sets the
I
LLEGAL
B
E
bit in P
CI
D
EVICE
S
TS
register.
■
During a memory cycle to the expansion ROM, if the address range defined in
expansion ROM space overlaps the address defined in Base Address 0 overlaps, the
AIC-6915 aborts the cycle and sets the
I
LLEGAL
O
VERLAP
bit.
■
Memory or indirect I/O access to the memory gap are defined as: 21'h6_0000 -
21'h7_FFFF.
■
Memory or indirect I/O access to the indirect I/O registers.
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