Data Sheet
June 1999
ORCA Series 3C and 3T FPGAs
Control Signal and Fast-Carry Routing
Programmable Logic Cells (continued)
PFU control signal and the fast-carry routing are per-
formed using the FINS structure and several dedicated
routing paths. The fast-carry (FC) routing resources
consist of a dedicated bidirectional segment between
each orthogonal pair of PLCs. This means that a fast-
carry can go to or come from each PLC to the right or
left, above or below the subject PLC. The FINS struc-
ture is used to control the switching of these fast-carry
paths between the fast-carry input (FCIN) and fast-
carry output (FCOUT) ports of the PFU.
BIDI Routing and SLIC Connectivity
The SLIC is connected to the rest of the PLC by the
bidirectional (BIDI) routing segments and the PFU out-
put switching segments coming from the PFU output
multiplexer. The BIDI routing segments (xBID) are
labeled as BL for BIDI-left and BR for BIDI-right. Each
set of BR and BL xBID segments is composed of ten
bidirectional lines (note that these lines are diagramed
as ten input lines to the SLIC and ten output lines from
the SLIC that can be used in a mutually exclusive fash-
ion). Because the SLIC is connected directly to the out-
puts of the PFU, it provides great flexibility in routing via
the xBID segments. The PFU routing segments, O[9:0],
only connect to their respective line in the SLL, SUL,
SUR, and SLR switching segment groups. That is, O9
only connects to SLL9, SUL9, SUR9, and SLR9. The
BIDI lines provide the capability to connect to the other
member of the routing set. That means, for example,
that O9 can be routed to BR8 or BL8. This connectivity
can be used as a means to distribute or gather signals
on intra-PLC routing without disturbing inter-PLC
resources. As described in the Switching Routing Seg-
ments subsection, the BIDI routing segments are also
used for routes to a diagonally adjacent PFU.
The PFU control inputs (CE, SEL, LSR, ASWE) and
CIN can be reached via the FINS by two special routing
segments, E1 and E2. The E1 routing segment pro-
vides connectivity between all of the xBID routing seg-
ments and the FINS. It is unidirectional from the BIDI
routing to the FINS. E1 also provides connectivity to the
PFU clock input via FINS for a local clock signal. The
E2 segment connects the SLIC DEC output to the FINS
and to a group of CIPS that provide bidirectional con-
nectivity with all of the BIDI routing segments. This
allows the DEC signal to be used in the PFU and/or
routed on the BIDI segments. It also allows signals to
be routed to the PFU on the xBID segments if the SLIC
DEC output is not used.
There is also a dedicated routing segment from the
FINS to the SLIC TRI input used for BIDI buffer 3-state
control.
In addition to the intra-PLC connections, the xBID and
output switching segments also have connectivity to
the x1, x5, and xL inter-PLC routing resources, provid-
ing an alternate routing path rather than using PLC
xSW segments. These connections also provide a path
to the 3-state buffers in the SLIC without encumbering
the xSW segments. In this manner, buffering or 3-state
control can be added to inter-PLC routing without dis-
turbing local functionality within a PFU.
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Lucent Technologies Inc.
AGERE [ AGERE SYSTEMS ]
