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Lucent Technologies Inc.
Lucent Technologies Inc.
21
Data Sheet
March 2000
ORCA OR3TP12 FPSC
Embedded Master/Target PCI Interface
PCI Bus Core Detailed Description
(continued)
Embedded Core/FPGA Interface Signal Descriptions
In Table 6, an input refers to a signal flowing into the FPGA logic (out of the embedded core) and an output refers
to a signal flowing out of the FPGA logic (into the embedded core).
Table 6. Embedded Core/FPGA Interface Signals
Symbol
I/O
Description
Clock
Domain
Master General Signals
fpga_mbusyn
O
FPGA Master Is Busy.
The FPGA application asserts this active-low signal to
indicate to the Master to assert the
reqn
signal until
fpga_mbusyn
becomes
inactive or the Target disconnects. This is helpful in PCI applications in which
Master has multiple high-priority transactions to be performed. Once asserted,
this signal needs to remain asserted for a minimum of two
pciclk
cycles.
FPGA Master Cycle Aborted by PCI Target.
The Master controller asserts
this active-high signal as an indication that the current cycle to the PCI bus has
been aborted.
Master State Counter.
Indicates the current state of the Master FIFO inter-
face. Details of the Master FIFO interface can be found in the PCI Bus Core
Master Controller Detailed Description section of this data sheet.
Master FIFO Clear.
This active-low signal is asynchronously asserted by the
FPGA application to clear the Master address, read, and write FIFOs, along
with
mstatecntr
. This signal does not reset the Master Controllers PCI state
machine within the embedded core, and therefore it is not recommended to be
used to terminate the current PCI transaction.
Master Logic Ready.
This active-high signal indicates that the Master FIFO
interface to the FPGA logic is ready. This signal will be inactive during PCI bus
resets and Master FIFO clears.
Master FIFO Address and Command Control Signals
maenn
O
Master Command/Start Address/Read Burst Length Enable.
This is an ac-
tive-low signal used to register the Master command word, read burst length,
and PCI start address into the Master controller registers. The type of data
transferred from the FPGA application will depend on the current state of
mstatecntr
and the interface mode (quad-port or dual-port). Further description
is provided in the Command/Address Setup section (see page 35) of the PCI
Bus Core Master Controller Detailed Description section.
ma_fulln
I
Master Address Register Full Flag.
This active-low signal indicates that the
Master address register is full and no new PCI Master transactions can be ac-
cepted from the FPGA application. This flag is cleared when the Master trans-
action is completed on the PCI bus. For Master writes,
ma_fulln
is cleared
when all write data has been transferred to the external Target. For Master
reads,
ma_fulln
is cleared when all read data has been received from the ex-
ternal Target, although all read data may not have been transferred to the FPGA
application.
pciclk
fpga_msyserror
I
fclk
*
mstatecntr[3:0]
I
fclk
*
mfifoclrn
O
—
m_ready
I
fclk
*
fclk
*
fclk
*
* The source of the clock (
fclk1
or
fclk2
) for the FIFO interface (Master or Target) is selected in the FPSC configuration manager.