US Patent 7606969 Programmable logic devices

An improved programmable logic device provides increased efficiency and enhanced flexibility in configuration of block memories and includes one or more memory blocks and a vertical shift register that receives the data to be loaded in the memory blocks. The PLD further provides a selection device for selecting the memory cells in the memory blocks that are to store the received data, and a control block for controlling the loading of the data in the memory blocks. The selection device includes an address counter connected to the input of an address decoder so as to enable the selection of addresses in the memory blocks.