Paired Counters
For more complex and accurate measurements and generations, a counter is paired with another counter with dedicated connections to and from each counter. This pairing allows you to perform such operations as finite pulse-train generations, higher accuracy frequency and period measurements, and cascaded edge counting. Paired counters are generally numbered sequentially. For example, ctr0 and ctr1 are a pair, ctr2 and ctr3 are a pair, and so on.