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21469 External Memory - Between 0x0200000 and 0x1200000

Question asked by yanava on Jun 20, 2011
Latest reply on Jun 22, 2011 by jeyanthi.jegadeesan

I've checked the documentation and, according to the ADS-21469 datasheet, the Address Space for ASYNC SRAM is:

 

Bank 0: 2M 0x0020 0000 – 0x003F FFFF

Bank 1: 4M 0x0400 0000 – 0x043F FFFF

Bank 2: 4M 0x0800 0000 – 0x083F FFFF

Bank 3: 4M 0x0C00 0000 – 0x0C3F FFFF

 

In a project where DDR2 is disabled, I am using the Bank 0 to control a network chip with SRAM like interface. One thing I don't understand is that when you click External Byte, the external memory starts from 0x0120 0000 and not 0x0020 0000 like you would normally expect.

 

If I write to 0x0020 0000 nothing happens (I can access this address but writing to it won't change anything), even disabling DDR and enablind the AMI. On top of that, my SRAM like device has it's first address mapped to position 0x0120 0000 so it's all working like the Address space starts from 0x0120 0000. I am probably missing some default configuration. This does not happen in other banks, is it something to do with running code from external ram?

 

Best regards.

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