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在高速系统中,一般采用DMA实现数据的高速传输。然而DMA技术有其局限性:一是传输速率不易提高。例如Z80-DMA的最高速率为2M字节/秒,欲采用更高速率的芯片,则价格昂贵;二是工作期间CPU无控制权,大数据流采集时大大降低了CPU的利用率;三是传输字长受系统CPU的限制,例如8位机传输16位以上数据时,传输速率难以提高;四是DMA的编程也较复杂。采用双端口RAM技术实现的数据高速传输可以
In high-speed systems, the use of DMA to achieve high-speed data transfer. However, DMA technology has its limitations: First, the transfer rate is not easy to increase. For example, the maximum speed of Z80-DMA is 2M bytes / second, and the higher the chip rate is, the more expensive it is. The other is that the CPU has no control during operation and greatly reduces the utilization of the CPU during the big data stream acquisition. Transfer word length by the system CPU limits, such as 8-bit machine to transfer more than 16 data, the transfer rate is difficult to improve; Fourth, DMA programming is more complicated. The use of dual-port RAM technology to achieve high-speed data transmission can be