您好!我们需要把tms320f28377d连接16位异步RAM(双口RAM)。发现地址总线连接方式有两种如下图。请问这两种接法有何差异,都能正常使用 吗?
一种是28377手册上推荐的做法,EM1BA[1]连接RAM的地址总线A0。
另一种是购买的开发套件做法,地址总线A0连接SRAM的A0,而没用使用EM1BA。
最后一个关联问题,图25-10中的EM1DQM作用?16位异步设备又是什么?它与异步存储器区别是什么?谢谢!
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您好!我们需要把tms320f28377d连接16位异步RAM(双口RAM)。发现地址总线连接方式有两种如下图。请问这两种接法有何差异,都能正常使用 吗?
一种是28377手册上推荐的做法,EM1BA[1]连接RAM的地址总线A0。
另一种是购买的开发套件做法,地址总线A0连接SRAM的A0,而没用使用EM1BA。
最后一个关联问题,图25-10中的EM1DQM作用?16位异步设备又是什么?它与异步存储器区别是什么?谢谢!
如果是接16位的异步存储器,则需要按照你的第一个图来连:EM1BA1 接设备的最低位。
Of special note is the connection between the EMIF and the external device's address bus. The EMIF
address pin EM1A[0] always provides the least significant bit of a 32-bit word address. Therefore, when
interfacing to a 16-bit or 8-bit asynchronous device, the EM1BA[1] and EM1BA[0] pins provide the leastsignificant bits of the halfword or byte address, respectively. Figure 25-9 and Figure 25-10 show the
mapping between the EMIF and the connected device's data and address pins for various programmed
data bus widths. The data bus width may be configured in the asynchronous n configuration register
(ASYNC_CSn_CR).
EM1DQM[x:0] O Active-low byte enables.
When interfacing to SDRAM, these pins are connected to the DQM pins of the SDRAM to
individually enable/disable each of the bytes in a data access.
When interfacing to an asynchronous device, these pins are connected to byte enables. See
Section 25.3.6 for details.
主要是字节访问使能。
ERIC