LSI LSI53C896, Technical Manual

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2-6 Functional Description
2.1.2.3 I/O Read Command
The I/O Read command reads data from an agent mapped in the I/O
address space. When decoding I/O cycles, the LSI53C896 decodes the
lower 32 address bits and ignores the upper 32 address bits.
2.1.2.4 I/O Write Command
The I/O Write command writes data to an agent mapped in the I/O
address space. When decoding I/O cycles, the LSI53C896 decodes the
lower 32 address bits and ignores the upper 32 address bits.
2.1.2.5 Reserved Command
The LSI53C896 does not respond to this command as a slave and it
never generates this command as a master.
2.1.2.6 Memory Read Command
The Memory Read command reads data from an agent mapped in the
Memory Address Space. The target is free to do an anticipatory read for
this command only if it can guarantee that such a read has no side
effects.
2.1.2.7 Memory Write Command
The Memory Write command writes data to an agent mapped in the
Memory Address Space. When the target returns “ready”, it assumes
responsibility for the coherency (which includes ordering) of the subject
data.
2.1.2.8 Configuration Read Command
The Configuration Read command reads the configuration space of each
agent. An agent is selected during a configuration access when its
IDSEL signal is asserted and AD[1:0] are 0b00. During the address
phase of a configuration cycle AD[7:2] addresses one of the 64 Dword
registers (where byte enables address the bytes within each Dword) in
the configuration space of each device. AD[63:11] are logical don’t cares
to the selected agent. AD[10:8] indicate which device of a multifunction
agent is being addressed.
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