Allegro FPGA System Planner Option

The Pin-Assignment of FPGAs is not an easy task. The FPGA designer starts the FPGA programming usually much earlier than the schematic or the layout will be designed. The FPGA programming software has no knowledge about the future layout, so the free programmable pins are assigned randomly. If later a pin swap is asked by the layouter to simplify the routing, it is mostly too late and the FPGA designer doesn't want to touch his nearly finished code again. The Allegro FPGA System Planner Option offers a way out of this dilemma.


Before the first line of the code is programmed, 3 experts (FPGA, schematic and layout) have the possibility to preplan approximately the layout. Given that the physical dimensions of the FPGAs are displayed on the drawing surface, a placement of the FPGAs and the connected big components can be realized. By simple assignment of interfaces (e.g. DDR2, PCI Express) numerious signals can be assigned and partial netlists can be created.

In the Allegro FPGA System Planner models for each FPGA are stocked to know how the internal pinout is and how caracteristics each pin has. With this informations an optimisation synthesis can be done to make sure that there are as few intersections of netlist connections as possbile. If now the FPGA programmer uses this reasonable pinout this will be a huge advantage which leads to easier designs and eventually less of layers in the PCB layer structure. As additional advantage the schematic developer gets a schematic in the OrCAD/Allegro format (including schematic symbols) and the layouter a placement (.brd) with the footprints and aire wires (rats).

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