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Altera_Forum
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20 years ago

absolute address accessing in NIOS2

HI, eveyone: i just a beginner of NIOS, i have a quetion about software development of absolute address's accessing. for example, the system have one 1kbytes ram, its start avalon address ...
Altera_Forum's avatar
Altera_Forum
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20 years ago

Hi oceanx,

I think that looks basically fine. However, what you might have problems with is the data cache (if you have one installed in your system) - the write might be stored there instead of written to main memory. I suggest you check the IOWR and IORD macros which are provided in HAL to bypass the cache:

Nios2 Documentation states that the 'volatile' keyword does not do the job because of a the cache machanism used in Nios2 (I believe it is called write-back cache).

<Nios II kit path>/components/altera_nios2/HAL/inc/io.h

Cheers,

-pkumpula