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Hi, I am using STR912FA44 CPU. I am tryring to access an external memory (SRAM) in non-mux mode. Because I am new in ARM, I used examples about EMI(I downloaded from http://www.st.com). While read operation every thing is ok, CS and Read Enable signals are acting correctly, however while write operation there is no change in CS and Write Enable signals. Before read and write operation I configure the external memory interface and I try to read and write. My question is this: Is there any difference in configuration between write and read operation? I am new in embedded system programming and ARM world, so I need your helps.
Thank you.
have you looked at AN2647 (Using the STR91xFA external memory interface (EMI)) at http://www.st.com ?
Yes I read. I have done everything that the document says. From now on, I get "write enable" and CS signal while writing, but I could not get the data which I write into the same address, in other words I could not write actually. What may be the cause of this problem? What can I do to solve the problem? It seems that I am asking some absurd things, however I am very new in this world, so I need some advices about methods to solve the problem.
some options: * do verify your memory access timing if you haven't done that yet. * are you sure your memory is properly connected to your external bus controller? * have you tried a RAM test?