Local routing network with selective fast paths for programmable logic device

Abstract

A routing network is associated with a logic island in a logic block of a programmable logic device and includes switches for each of feedback, street, and highway networks. Some of the switches include multiple stages. The street network switch receives the signals from the feedback network switch, signals from neighboring highway network switches, and direct feedback from selected logic island outputs and provides outputs to the logic island. The street network switch includes multiple stages, where outputs to the logic island are provided directly by each stage in the street network switch. The output terminals of a first stage of the street network switch that are connected to the logic island are also connected to the second stage of the street network switch. The second stage of the street network switch receives feedback output signals from the feedback network and directly from the associated logic island.