Em 25/3/2011 18:08, Olin Lathrop escreveu:
> Isaac Marino Bavaresco wrote:
>> If I don't register somewhere each block as it is received, the only
>> way
>> to tell if a block was already received would be to scan it from begin
>> to end to find a value different to 0xff.
>> Besides being too time-consuming, if a block full of 0xff is received
>> it
>> will always be detected as not received.
> OK, so you use a single erase block somewhere with individual bits
> corresponding to uploaded blocks.


Not bits, one word per block, because I can program a minimum of one
word at a time.
It is a little wasteful but that doesn't matter at all because there is
plenty of unused FLASH.

The device has 128k instructions plus 3k spare for the boot-loader.

The area from 0 to 63k-1 instructions is reserved for the application.

>From 63k to 64k-1 is reserved for the copy of the application's saved
reset vector (goto instruction to the start of the application), which
is replaced in row 0 by the reset vector of the boot-loader. This area
is mostly empty.

>From 64k to 127k-1 is reserved for the new firmware being downloaded. It
is an exact copy of the final firmware, shifted up 64k instructions.
>From 127k to 128k-1 is reserved for register the received blocks and
other control information (number of blocks expected, CRC of the whole
new firmware, version of the new firmware, etc.)

The boot-loader is located from 128k to the end of the memory.


>   These bits start out as 1 and you flip
> them to 0 when the corresponding block is received.  In any case, you sho=
uld
> checksum the whole uploaded image before attempting to write it to the ap=
p
> area.
>
> However, what does this have to do with the bootloader doing word versus
> page writes?


The word programming is to mark each entry of the received-block list.


Isaac

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