Altera PCI Compiler - Manual (Page 200)

3–126 User Guide Version 11.1 Altera Corporation
PCI Compiler October 2011
Master Mode Operation
Disconnect Without Data
The target device issues a disconnect without data if it is unable to
transfer additional data during the transaction. The signal pattern for this
termination is described in
“Disconnect” on page 3–79 . When the
pci_mt64 and pci_mt32 functions end a transaction because of a
disconnect without data, they assert lm_tsr[6] until the beginning of
the next master transaction.
Disconnect with Data
The target device issues a disconnect with data if it is unable to transfer
additional data in the transaction. The signal pattern for this termination
is described in
“Disconnect” on page 3–79 . When the pci_mt64 and
pci_mt32 functions end a transaction because of a disconnect with data,
they assert lm_tsr[7] until the beginning of the next master
transaction.
Target Abort
A target device issues this type of termination when a catastrophic failure
occurs in the target. The signal pattern for a target abort is shown in
“Target Abort” on page 3–86 . When the pci_mt64 and pci_mt32
functions end a transaction because of a target abort, they assert the
tabort_rcvd
signal, which is the same as the PCI status register bit 12.
Therefore, the signal remains asserted until it is reset by the host.
Master Abort
The pci_mt64 and pci_mt32 functions terminate the transaction with
a master abort when no target claims the transaction by asserting
devseln
. Except for special cycles and configuration transactions, a
master abort is considered to be a catastrophic failure. When a cycle ends
in a master abort, the pci_mt64 and pci_mt32 functions inform the
local-side device by asserting the mabort_rcvd signal, which is the same
as the PCI status register bit 13. Therefore, the signal remains asserted
until it is reset by the host.