
28
Lucent Technologies Inc.
Data Sheet
June 1999
ORCA Series 2 FPGAs
Programmable Input/Output Cells 
(continued)
PIC Routing Resources
The PIC routing is designed to route 4-bit wide buses 
efficiently. For example, any four consecutive I/O pads 
can have both their input and output signals routed into 
one PLC. Using only PIC routing, either the input or 
output data can be routed to/from a single PLC from/to 
any eight pads in a row, as in Figure 25.
The connections between PLCs and the I/O pad are 
provided by two basic types of routing resources. 
These are routing resources internal to the PIC and 
routing resources used for PIC-PLC connection. 
Figure 26 and Figure 27 show a high-level and detailed 
view of these routing resources, respectively.
5-4504(F)
Figure 25. Simplified PIC Routing Diagram
The PIC’s name is represented by a two-letter designa-
tion to indicate on which side of the device it is located 
followed by a number to indicate in which row or col-
umn it is located. The first letter, P designates that the 
cell is a PIC and not a PLC. The second letter indicates 
the side of the array where the PIC is located. The four 
sides are left (L), right (R), top (T), and bottom (B). The 
individual I/O pad is indicated by a single letter (either 
A, B, C, or D) placed at the end of the PIC name. As an 
example, PL10A indicates a pad located on the left 
side of the array in the tenth row.
Each PIC has four pads and each pad can be config-
ured as an input, an output (3-statable), a direct output, 
or a bidirectional I/O. When the pads are used as 
inputs, the external signals are provided to the internal 
circuitry at IN[3:0]. When the pads are used to provide 
direct inputs to the latches/FFs, they are connected 
through DIN[3:0]. When the pads are used as outputs, 
the internal signals connect to the pads through 
OUT[3:0]. When the pads are used as direct outputs, 
the output from the latches/flip-flops in the PLCs to the 
PIC is designated DOUT[3:0]. When the outputs are 
3-statable, the 3-state enable signals are TS[3:0].
Routing Resources Internal to the PIC
For inter-PIC routing, the PIC contains 14 lines used to 
route signals around the perimeter of the FPGA. Figure 
25 shows these lines running vertically for a PIC 
located on the left side. Figure 26 shows the lines run-
ning horizontally for a PIC located at the top of the 
FPGA.
PXL Lines.
 Each PIC has two PXL lines, labeled 
PXL[1:0]. Like the XL lines of the PLC, the PXL lines 
span the entire edge of the FPGA. 
PXH Lines.
 Each PIC has four PXH lines, labeled 
PXH[3:0]. Like the XH lines of the PLC, the PXH lines 
span half the edge of the FPGA. 
PX2 Lines. 
There are four PX2 lines in each PIC, 
labeled PX2[3:0]. The PX2 lines pass through two adja-
cent PICs before being broken. These are used to 
route nets around the perimeter equally a distance of 
two or more PICs.
PX1 Lines.
 Each PIC has four PX1 lines, labeled 
PX1[3:0]. The PX1 lines are one PIC long and are 
extended to adjacent PICs by enabling CIPs.
PAD D
I/O3
4
PXL
2
CK
2
PIC
SWITCHING
MATRIX
PAD C
I/O2
4
PAD B
I/O1
4
PAD A
I/O0
4
PXH
4
PX2
4
PX1
4
PLC X4
4
PLC X1
4
PLC PSW
5
PLC DOUT
4
PLC XL
4
PLC XH
4
PLC X1
4
PLC X4
4
PLC DIN
4
PXL
2
PXH
4
PX2
4
PX1
4