Altera PCI Compiler - Manual (Page 94)

3–20 User Guide Version 11.1 Altera Corporation
PCI Compiler October 2011
PCI Bus Signals
Target Local-Side Signals
Table 3–7 summarizes the target interface signals that provide the
interface between the PCI MegaCore function and the local-side
peripheral device(s) during target transactions.
1 When a local side transaction is not in progress, local side inputs
should be driven to the deasserted state.
Table 3–7. Target Signals Connecting to the Local Side (Part 1 of 3)
Name Type Polarity Description
lt_abortn Input Low Local target abort request. The local side should assert this
signal requesting the PCI MegaCore function to issue a target
abort to the PCI master. The local side should request an abort
when it has encountered a fatal error and cannot complete the
current transaction.
lt_discn Input Low Local target disconnect request. The lt_discn input
requests the PCI MegaCore function to issue a retry or a
disconnect. The PCI MegaCore function issues a retry or
disconnect depending on when the signal is asserted during a
transaction.
The PCI bus specification requires that a PCI target issues a
disconnect whenever the transaction exceeds its memory
space. When using PCI MegaCore functions, the local side is
responsible for asserting
lt_discn if the transaction crosses
its memory space.