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代码运行效率问题

Other Parts Discussed in Thread: OMAP-L137

请问专家:

        1.在omap-l137中,程序在片内dspL2RAM、共享ram、emifb外挂的sdram三者中的执行效率分别有多大区别。或者说cpu访问这三段空间的时间相差多少?尤其是dspL2RAM的访问效率,手册里找不到。

        2.我看emifb的时钟周期可以通过SYSCLK2产生,也可以通过SYSCLK5和DIV4P5产生,好像通过SYSCLK2产生的时钟是cpu/2分频,那么如何让emifb的时钟由SYSCLK2产生?我在手册里找不到,请指点。

  • 2,EMIFB的时钟配置,如下所描述:

    The EMIFB requires two input clocks to source VCLK and MCLK (see Figure 7-3):
    • VCLK is sourced from SYSCLK2 that clocks the peripheral bus interface of EMIFB
    • MCLK, which sets the clock rate for the I/O clock (EMB_CLK), is sourced from either SYSCLK5 or
    DIV4P5. The EMB_CLKSRC bit in the chip configuration 3 register (CFGCHIP3) of the System
    Configuration Module controls whether SYSCLK5 or DIV4P5 is selected as the clock source for MCLK.

    参见技术手册章节:7.3.2 EMIFB Clocking

  • 1,通过Figure 4-1. System Interconnect Block Diagram可以看出不同的存储空间访问需要经过那些不同的总线路径。但这些总线路径并没有一个明确的效率指标。

    但总体的速度性能是:dspL2RAM > 共享ram > emifb外挂的sdram。