Re: [avr-gcc-list] The "Temporary Buffer"

[Christoph Plattner]

Hello !

I don't know anything about the architecture of the write
algorism and the SPM structure, but I really think, that
such a buffer is implemented as a separate area in the
chip, not colliding to any part of RAM or ROM. But this
depends on the size of it.
Dependent on the page-size (sector size), there a flash
(eeprom) chips, where the user has to write without
interruption bytes in the programming algorithm for one
sector. Perhaps the buffer has the size of such one sector ...

Sorry, that the answer is so weak here.

Bye
Christoph P.

ken restivo wrote:
> 
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> I am writing a little boot loader for an ATmega163. I have implemented a 
> modified version of the page write routine from the data book, in assembler. 
> So far so good.
> 
> I am concerned about the mention in the databook of a "temporary buffer". The 
> docs claim that the SPM instruction reads and writes a temporary buffer.  
> However, a search through the docs for the text "temporary buffer" didn't 
> turn up any description of *what* exactly this "temporary buffer" is, or 
> where it is located.
> 
> I have also read the AVR109 app note and looked through Atmel's sample 
> bootloader source code as well, with no answers found there.
> 
> This worries me. For example, I may want to load more than one page at a time 
> of app code into RAM from my serial port, do a crc check, etc, and only then 
> start iteratively calling the page write routine, but I don't want to stomp 
> on anything inadvertently.
> 
> Any ideas what/where this "temporary buffer" actually is so I can stay out of 
> its way?
> 
> - -ken
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