2 special cycle command, 3 i/o read command, 4 i/o write command – Avago Technologies LSI53C895A User Manual

Page 31: 5 reserved command, 6 memory read command, 7 memory write command, 8 configuration read command

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PCI Functional Description

2-5

2.1.2.2 Special Cycle Command

The LSI53C895A does not respond to this command as a slave and it
never generates this command as a master.

2.1.2.3 I/O Read Command

The I/O Read command reads data from an agent mapped in I/O
address space. All 32 address bits are decoded.

2.1.2.4 I/O Write Command

The I/O Write command writes data to an agent mapped in I/O address
space. All 32 address bits are decoded.

2.1.2.5 Reserved Command

The LSI53C895A 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.

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