The structure of the General Purpose PLD consists of a programmable AND ARRAYand 2 sets of I/O Macrocells. The ARRAY has 37 input signals, same as the DPLD.From these inputs, “ANDed” functions are generated as product term inputs to themacrocells. The I/O Macrocell sets are named after the I/O Ports they are linked to,e.g., the macrocells connected to Port B are named PB Macrocells. The PB macrocellsare registered macrocells with D-type flip-flops, where PA consists of combinatorialmacrocells. Low Cost Field Programmable Microcontroller Peripherals