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184 21555 Non-Transparent PCI-to-PCI Bridge User Manual
List of Registers
Table 116. Primary SERR# Disable Register
This register may be preloaded by serial ROM or programmed by the local processor before host
configuration. This register controls the ability of the 21555 to assert p_serr_l for a particular condition. When
the bit is a 0, the assertion of p_serr_l is not masked for this event.
When the bit is a 1, the assertion of p_serr_l is masked for this event.
• Primary byte offset: D4h
• Secondary byte offset: D4h
Bit Name R/W Description
0
Downstream
Delayed
Transaction
Master
Time
-out
R/W
Disables p_serr_l assertion when a downstream master time
-out condition
is detected and the downstream transaction is discarded.
Reset value is 0
1
Downstream
Delayed Read
Transaction
Discarded
R/W
Disables p_serr_l assertion when 21555 discards a downstream delayed
read transaction request after receiving 2
24
target retries from secondary bus
target.
Reset value is 0
2
Downstream
Delayed Write
Transaction
Discarded
R/W
Disables p_serr_l assertion when 21555 discards a downstream delayed
write transaction request after receiving 2
24
target retries from secondary
bus target.
Reset value is 0
3
Downstream
Posted Write
Data Discarded
R/W
Disables p_serr_l assertion when 21555 discards a downstream posted
write transaction after receiving 2
24
target retries from secondary bus target.
Reset value is 0
4
Target Abort
during
Downstream
Posted Write
R/W
Disables p_serr_l assertion when 21555 detects a target abort on the
secondary interface in response to a downstream posted write.
Reset value is 0
5
Master Abort
during
Downstream
Posted Write
R/W
Disables p_serr_l assertion when the 21555 detects a master abort on the
secondary interface when initiating a downstream posted write.
Reset value is 0
6
Downstream
Posted Write
Parity Error
R/W
Disables p_serr_l assertion when the 21555 detects s_perr_l asserted
during a downstream posted write.
Reset value is 0
7 Reserved R Reserved. Returns 0 when read.
Table 117. Secondary SERR# Disable Register
This register may be preloaded by serial ROM or programmed by the local processor before host
configuration. This register controls the ability of the 21555 to assert s_serr_l for a particular condition. When
the bit is a 0, the assertion of s_serr_l is not masked for this event.
When the bit is a 1, the assertion of s_serr_l is masked for this event.
• Primary byte offset: D5h
• Secondary byte offset: D5h
Bit Name R/W Description
0
Upstream Delayed
Transaction Master
Timeout
R/W
Disables s_serr_l assertion when an upstream master timeout
condition is detected and the upstream transaction is discarded.
Reset value is 0