Altera PCI Compiler - Manual (Page 93)

Altera Corporation User Guide Version 11.1 3–19
October 2011
Functional Description
l_cmdo[3..0] Output – Local command output. The l_cmdo[3..0] bus is driven by the PCI
MegaCore functions during target transactions. It has the bus
command and the same timing as the
l_adro[31..0] bus. The
command is encoded as presented on the PCI bus.
l_ldat_ackn Output Low Local low data acknowledge. The l_ldat_ackn output is used
during target write and master read transactions. When asserted,
l_ldat_ackn indicates that the least significant DWORD is being
transferred on the l_dato[31..0] bus, i.e., when l_ldat_ackn
is asserted, the address of the transaction is on a QWORD boundary
( ad[2..0] = B"000 " ). The signals lm_ackn or lt_ackn must be
used to qualify valid data.
During target read transactions, l_ldat_ackn is used to indicate
the first DWORD transferred to the PCI side. If the address of the
transaction is a QWORD boundary, the l_ldat_ackn signal is
asserted.
This signal is not implemented in the pci_mt32 and pci_t32
functions.
l_hdat_ackn Output Low Local high data acknowledge. The l_hdat_ackn output is used
during target write and master read transactions. When asserted,
l_hdat_ackn indicates that the most significant DWORD is being
transferred on the l_dato[31..0] bus. In other words, when
l_hdat_ackn is asserted, the address of the transaction is not a
QWORD boundary ( ad[2..0] = B"100 " ). The signals lm_ackn
or lt_ackn must be used to qualify valid data.
During target read transactions, l_hdat_ackn is used to indicate
the first DWORD transferred to the PCI side. If the address of the
transaction is not a QWORD boundary, l_ldat_ackn is deasserted
and l_hdat_ackn is asserted.
This signal is not implemented in the pci_mt32 and pci_t32
functions.
Table 3–6. PCI Local Address, Data, Command & Byte Enable Signals (Part 3 of 3)
Name Type Polarity Description