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am1808emif口配置问题

Other Parts Discussed in Thread: AM1808

你好!我现在用am1808的emif口作为数据总线传输信号,数据位宽为16bit。将ASIZE设置为16-bit data bus,发现在读写的时候,每读写一次读写使能信号出现使能两次。比如我在读的时候,用示波器抓取CS使能信号及WE使能信号,读一次,在CS使能期间,会出现两次WE使能。另外我将ASIZE设置为8-bit data bus,读一次,在CS使能期间,会出现四次WE使能。然后我将ASIZE设置为2时,读一次,在CS使能期间,就只会出现一次WE使能,但是低位地址线EMA_BA就被禁止了。请问是不是还有其他地方需要配置数据宽度,使得数据位宽为16bit时,只出现一次读写使能?

下面是ASIZE配置

ASIZE             0-3h          Asynchronous Data Bus Width. This field defines the width of the asynchronous device's data bus.


                              0          8-bit data bus
                            1h         16-bit data bus
                      2h-3h          Reserved

另外,SDRAM Configuration Register (SDCR)中有个NM参数,改变这个设置也没有任何变化

NM         Narrow mode bit. This bit defines whether a 16- or 32-bit-wide SDRAM is connected to the EMIFA.
This bit field must always be set to 1. Writing to this field triggers the SDRAM initialization
sequence.

       0             32-bit SDRAM data bus is used.
       1             16-bit SDRAM data bus is used.