[DIS] Butterfly bootloader protocol (AVR109 update)

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Here is a list of the actual commands recognized by the Butterfly serial bootloader, as opposed to the general AVRProg commands shown in the AVR109 Application Note. Mostly they agree, but there are a few differences.

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Chuck Baird

"I wish I were dumber so I could be more certain about my opinions. It looks fun." -- Scott Adams

http://www.cbaird.org

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The list above is for version 3 of the bootloader. Ever since version 4 was released I've been meaning to take a look at it and see what changed. I have finally gotten around to doing that, and here's the good/bad news:

All they did was remove some commands. No fixes of the minor and not quite so minor bugs in the bootloader. They removed the following functionality (command is in parentheses):

Read lock bits (r)
Write lock bits (l)
Read low fuse bits (F)
Read high fuse bits (N)
Read extended fuse (Q)

It will still lock up if given an odd byte count, still leaves a bit of a mess with the pin change interrupts active, and so on as noted previously. But perhaps the casual user is better protected from shooting him/herself in the foot by not being able to dingle the fuses.

Chuck Baird

"I wish I were dumber so I could be more certain about my opinions. It looks fun." -- Scott Adams

http://www.cbaird.org