The Virtex™-4 user access register (USR_ACCESS_VIRTEX4) is a 32-bit register thatprovides direct access to bitstream data by the FPGA fabric. It is useful for loadingPowerPC™ 405 (PPC405) processor caches and/or other data into the FPGA after the FPGAhas been configured, thus achieving partial reconfiguration. The USR_ACCESS_VIRTEX4register is programmed through the bitstream with a command that writes a series of 32-bitwords.
The Virtex™-4 user access register (USR_ACCESS_VIRTEX4) is a 32-bit register thatprovides direct access to bitstream data by the FPGA fabric. It is useful for loadingPowerPC™ 405 (PPC405) processor caches and/or other data into the FPGA after the FPGAhas been configured, thus achieving partial reconfiguration. The USR_ACCESS_VIRTEX4register is programmed through the bitstream with a command that writes a series of 32-bitwords.
很多嵌入式系統,特別是應用于圖像處理與高速數據采集等場合的嵌入式系統,都需要高速緩存大量的數據。DDR(Double Data Rate,雙數據速率)SDRAM由于其速度快、容量大,而且價格便宜,因此能夠很好地滿足上述場合對大量數據緩存的需求。但DDR SDRAM的接口不能直接與現今的微處理器和DSP的存儲器接口相連,需要在其間插入控制器實現微處理器或DSP對存儲器的控制。