In Summary

So there you have it. FPGA designs consist of blocks of combinational logic that do all the processing and DFFs that store values and control the flow of data.

The designs themselves are broken down into modules. Modules can be used by other modules and can even have parameters to customize each instantiation of them. Every time a module is instantiated, the circuit for it is duplicated in the FPGA.

When designing hardware, it is important to think about how that design could be implemented to create efficient circuits.

In the case of our blinker, if we didn’t care about the rate of blinking, the first version of the module would take a lot less resources to implement. This is because it doesn’t need a comparator to check the value of the counter. It simply keeps adding 1 and uses the natural overflow of binary addition to reset the counter.