Em 25/3/2011 18:54, Olin Lathrop escreveu:
> Dwayne Reid wrote:
>> In other words, his boot-loader is responsible for saving the new
>> firmware to scratchpad FLASH as it received.  That requires word
>> writes.
> I don't consider that a "bootloader" function.  It's really a uploader
> function that he happened to put in the bootloader code.
>
> In any case, I still don't see why word writes are necessary.  First, it
> would make sense for the upload blocks to be the same size as the write
> blocks.


Yes, the upload blocks are the same size of a program row (64
instructions or 192 bytes)



>   However, even if that is not possible or desirable, I would expect
> the whole upload area to be erased once before any blocks are uploaded.


Yes, the whole temporary area is erased when a special block (called
header) is received and the process begins.
This block also contains the CRC of the whole new firmware, a number to
identify the version of the firmware and the number of blocks to be
received and programmed.

Each block (header of program) has its own CRC also.


> Then blocks are written as received without any erases.  Even if partial
> pages are written, it still makes sense to use page writes.  Even if you'=
re
> writing just two words in a page, why would you do two separate word writ=
es
> when they can be written at the same time with a single page write?  It
> doesn't make sense.

The blocks (rows) of 192 bytes are programmed using page writes, but one
additional word write is made to a different
area to signal that that particular block was received.


Isaac

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