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"Page" in NOR flash?

Anonymous
Anonymous

Hi All,

 

I would like to ask a question NOR flash.

 

 

 

 

Does there exist the concept of “page” in NOR flash?

 

In function norflash_test( ) of EVM6437, there is the following code snippet:

flash_test.c said:

/* Determine the total # number of pages of Flash */
 npages = FLASH_PAGES;
   nbytes = npages * FLASH_PAGESIZE;
    printf( "     %d Pages\n", npages );
   printf( "     %d Mbytes\n", nbytes >> 20 );

 

Whereas within the command definition of Spansion’s NOR flash which is used on EVM6437, there is no such thing of “page” at all. There are only two types of erase:

1)      Chip erase

2)      Sector erase

And none of the other operations seem to deal with “page” at all.

 

So how come the “page” and “page size” in the function? Are they necessary in using NOR flash?

 

 

 

Thanks,

Zheng

  • 0
    TI__Expert 5750 points

    Quoting from expert.

    "NOR flash must be erased and written in blocks, but for read access it can be treated just like an async memory attached to the memory interface. So it needs address lines equivalent to its memory size.  For NAND flash, everything must be done in terms of pages/blocks (reads/writes can happen on smaller pages, erases still happen on blocks).  Address data is multiplexed on the same bus as the actual memory contents data, so, in general, it does not need any memory interface address lines (though we typically use two as the ALE and CLE)."