MULTI-PORT MEMORY UNIT, AND DATA TRANSFER METHOD

摘要

PROBLEM TO BE SOLVED: To rapidly process massive data, by providing an SRAM, DRAMs and two external IO ports, providing three IO ports accessing the external ports and the DRAMs in the SRAM and parallel reading out the updated data stored in the SRAM through all three ports. SOLUTION: The DRAM 12 consists of four 4 M bits memory banks respectively constituted of 512 rows×32 columns×256 bits. The SRAM 16 consists of 4 K bits constituted of 16 lines×16 words×16 bits to transfer the 16 bits data between IO data pins 18, 20 of external ports A, B through two SRAM ports corresponding to respective pins. Further, the SRAM 16 transfers a 256 bits data block by a global input/output bus in between with the DRAM 12 through a third SRAM port. Three SRAM ports are constituted so that multiple read-out operation are performed parallel.