82443ZX Datasheet, PDF (92/116 Pages) Intel Corporation – Intel® 440ZX AGPset: Host Bridge/Controller

Functional Description
Table 4-6. Host Responses supported by the 82443ZX
RS2# RS1# RS0#
Description
82443ZX Support
0
0
0 idle
To avoid deadlock, this response is generated when a
0
0
1 Retry Response
resource cannot currently be accessed by the
processor. PCI-directed reads, writes, DRAM locked
reads, AGP reads and writes can be retried.
This response can be returned for all transactions that
can be executed ‘out of order.’ PCI-directed reads
0
1
0 Deferred Response (memory, I/O and Interrupt Acknowledge) and writes
(I/O only), and AGP directed reads (memory and I/O)
and writes (I/O only) can be deferred.
0
1
1 Reserved
Reserved
1
0
0 Hard Failure
Not supported.
This is for transactions where the data has already
1
0
1
No Data Response
been transferred or for transactions where no data is
transferred. Writes and zero length reads receive this
response.
This response is given for those transactions where
1
1
0 Implicit Writeback
the initial transactions snoop hits on a modified cache
line.
1
1
1
Normal Data
Response
This response is for transactions where data
accompanies the response phase. Reads receive this
response.
4-12
82443ZX Host Bridge Datasheet