Rainbow Electronics DS31256 - Manual (Page 135)

DS31256
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10.1.7 PCI Target Abort
Targets can also abort the current transaction, which means they do not wish for the initiator to attempt
the request again. No data is transferred in a target abort scenario. A target abort is signaled to the
initiator by the simultaneous assertion of PSTOP and deassertion of PDEVSEL (
Figure 10-8 ). When the
Envoy is a target, it only issues a target abort when the host is accessing the local bus. This occurs when
the host attempts a bus transaction with a combination of byte enables (PCBE) that are not supported by
the local bus. If such a scenario occurs, it reports through the target-abort-initiated status bit in the PCI
command/status configuration register (Section
10.2 ). See Section 11.1 for details about local bus
operation. When the Envoy is a bus master, if it detects a target abort, it reports through the target abort
detected by master status bit in the PCI command/status configuration register (Section
10.2 ).
Figure 10-8. PCI Target Abort
1 2 3 4 5 6 7 8 9 10
PCLK
PFRAME
PSTOP
PDEVSEL
PTRDY