In APEXTM II devices, enhanced embedded system blocks (ESBs) support memory structures, such as single-port and dual-port RAM. Additionally,in APEX II devices, ESBs support bidirectional dual-port RAM. In this mode, each ESB has two ports that allow two different read or write operations simultaneously. In APEX II 、 devices, the ESB can be split into two separate single-port 2K RAM blocks.……