FSMC configuration

[sshumway]

Posted on May 20, 2013 at 14:55

I'm using an STM32f207 part and looking into the FSMC configuration. As a place to start, I took a look at the initialization code for this component as presented in u-boot.

At the start of the u-boot FSMC initialization, the programmer states just before setting the BCR: ''Fake BCR read; if don't do this, then BCR remains configured with defaults.'' Can anyone tell me if this is correct? I see no reference to it in any of the documentation. Did I miss something? or is the author incorrect? Thanks Steve Shumway #fsmc-external-ram

[sshumway]

Posted on May 20, 2013 at 15:49

As usual, after I hit the ''ok'' button to post this, I remembered the central reason this comment struck me as suspicious:

If we think about how a RISC processor (such as ARM) works, Every time we do anything to a memory mapped I/O such as FSMC the first machine instruction executed will be some sort of: LDR Rt, [Rn, #foo] Right away, there is the ''Fake BCR read''. Comment invited. Thanks Steve Shumway