OR2T15B7BA352-DB 查看數據表（PDF） - Lattice Semiconductor
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OR2T15B7BA352-DB Datasheet PDF : 200 Pages
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Data Sheet
November 2006
ORCA Series 2 FPGAs
Programmable Logic Cells (continued)
PLC Routing Resources
INDEPENDENT CIP
B
Generally, the ispLEVER development system is used
=
CD
to automatically route interconnections. Interactive
routing with the ispLEVER design editor (EPIC) is also
available for design optimization. To use EPIC for inter-
active layout, an understanding of the routing
S resources is needed and is provided in this section.
The routing resources consist of switching circuitry and
metal interconnect segments. Generally, the metal
E lines which carry the signals are designated as routing
nodes (lines). The switching circuitry connects the rout-
ing nodes, providing one or more of three basic func-
IC tions: signal switching, amplification, and isolation. A
D net running from a PFU or PIC output (source) to a
PLC or PIC input (destination) consists of one or more
lines, connected by switching circuitry designated as
V E configurable interconnect points (CIPs).
The following sections discuss PLC, PIC, and interquad
E routing resources. This section discusses the PLC
U switching circuitry, intra-PLC routing, inter-PLC routing,
and clock distribution.
D IN Configurable Interconnect Points
The process of connecting lines uses three basic types
T of switching circuits: two types of configurable intercon-
T nect points (CIPs) and bidirectional buffers (BIDIs). The
basic element in CIPs is one or more pass transistors,
C each controlled by a configuration RAM bit. The two
N types of CIPs are the mutually exclusive (or multi-
plexed) CIP and the independent CIP.
E A mutually exclusive set of CIPs contains two or more
O CIPs, only one of which can be on at a time. An inde-
L pendent CIP has no such restrictions and can be on
independent of the state of other CIPs. Figure 19
SE DISC shows an example of both types of CIPs.
A
A
B
MULTIPLEXED CIP
O
A
CD
2
A
B
B
O
C
C
f.13(F)
Figure 19. Configurable Interconnect Point
3-Statable Bidirectional Buffers
Bidirectional buffers provide isolation as well as amplifi-
cation for signals routed a long distance. Bidirectional
buffers are also used to drive signals directly onto
either vertical or horizontal XL and XH lines (to be
described later in the inter-PLC routing section). BIDIs
are also used to indirectly route signals through the
switching lines. Any number from zero to eight BIDIs
can be used in a given PLC.
The BIDIs in a PLC are divided into two nibble-wide
sets of four (BIDI and BIDIH). Each of these sets has a
separate BIDI controller that can have an application
net connected to its TRI input, which is used to 3-state
enable the BIDIs. Although only one application net
can be connected to both BIDI controllers, the sense of
this signal (active-high, active-low, or ignored) can be
configured independently. Therefore, one set can be
used for driving signals, the other set can be used to
create 3-state buses, both sets can be used for 3-state
buses, and so forth.
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