The effect of switch box flexibility on routability of field programmable gate arrays

The relationship between the routability of a field programmable gate array (FPGA) and the flexibility of its interconnection structures is explored. A set of industrial circuits are implemented as FPGAs in a range of routing structures with varying flexibility. Experiments indicate that high flexibility is essential for the connection box that joint the logic blocks to the routing channel, but a relatively low flexibility is sufficient for switch boxes at the junction of horizontal and vertical channels