Managing Design Changes using a Stub FPGA Project

It is often the case that the PCB and FPGA projects are not designed by the same person. Indeed, they might not be developed on the same computer or even in the same locale. In such cases, a method of passing design changes between projects is needed, whereby only relevant information is passed, without the need to send the entire project – PCB or FPGA – back and forth between locations and designers. The answer to remote development of projects that need to be kept synchronized, with a view to bringing them together at a future date, is the Stub.

The Stub is essentially a satellite FPGA project that is initially produced by the PCB designer. It is used to pass changes made to the PCB project on to the FPGA designer, who imports changes from the Stub FPGA projectinto the full FPGA design project. Any changes made by the FPGA designer are passed back into the stub, which in turn is sent back to the PCB designer who, to all intents and purposes, treats the Stub as if it were the real, full-blown FPGA project.

Figure 1 illustrates the two processes of maintaining design changes between linked PCB and FPGA projects – with and without the use of a Stub FPGA project.

Figure 1. Use of a Stub FPGA project to keep remote projects synchronized.

The name Stub does not actually appear anywhere, rather it is a term of reference used to reflect the fact that the schematic sheet in the FPGA project does not contain a complete design – no FPGA components, processors, virtual instruments, or wiring – it simply contains the top-levels ports for the full FPGA design.

Creating a Stub FPGA Project
Passing Changes to the FPGA Designer
Passing Changes to the PCB Designer