Altera PCI Compiler - Manual (Page 98)

3–24 User Guide Version 11.1 Altera Corporation
PCI Compiler October 2011
PCI Bus Signals
Master Local-Side Signals
Table 3–9 summarizes the pci_mt64 and pci_mt32 master interface
signals that provide the interface between the PCI MegaCore function
and the local-side peripheral device(s) during master transactions.
1 When a local side transaction is not in progress, local side inputs
should be deasserted.
Table 3–9. PCI Master Signals Interfacing to the Local Side (Part 1 of 2)
Name Type Polarity Description
lm_req32n Input Low Local master request 32-bit data transaction. The local side asserts
this signal to request ownership of the PCI bus for a 32-bit master
transaction. To request a master transaction, it is sufficient for the
local-side device to assert
lm_req32n for one clock cycle. When
requesting a 32-bit transaction, only l_adi[31..0] for a master
write transaction or l_dato[31..0] for a master read
transaction is valid.
The local side cannot request the bus until the current master
transaction has completed. After being granted mastership of the
PCI bus, the
lm_req32n signal should be asserted only after
lm_tsr[3] is deasserted.
lm_req64n Input Low Local master request 64-bit data transaction. The local side asserts
this signal to request ownership of the PCI bus for a 64-bit master
transaction. To request a master transaction, it is sufficient for the
local side device to assert
lm_req64n for one clock cycle. When
requesting a 64-bit data transaction, pci_mt64 requests a 64-bit
PCI transaction. When the target does not assert its ack64n
signal, the transaction will be 32 bits. In a 64-bit master write
transaction where the target does not assert its
ack64n signal,
pci_mt64 automatically accepts 64-bit data on the local side and
multiplexes the data appropriately to 32 bits on the PCI side. When
the local side requests 64-bit PCI transactions, it must ensure that
the address is at a
QWORD boundary. This signal is not implemented
in pci_mt32 .
The local side cannot request the bus until the current master
transaction has completed. After being granted mastership of the
PCI bus, the
lm_req64n signal should be asserted only after
lm_tsr[3] is deasserted.
lm_lastn Input Low Local master last. This signal is driven by the local side to request
that the
pci_mt64 or pci_mt32 master interface ends the
current transaction. When the local side asserts this signal, the PCI
MegaCore function master interface deasserts
framen as soon as
possible and asserts irdyn to indicate that the last data phase has
begun. The local side must assert this signal for one clock cycle to
initiate the end of the current master transaction.