Bootloader advice

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I have been doing some searching for a bootloader for an ATMEGA8. I have found various solutions for PIC and ATMEGA....but I'm wondering if there is some defacto goto solution that is common knowledge among the AVR veterans?

The actual Boot code needs to be <=256 bytes

I would like the host app to be such that it can be configured and compiled and then used by an end customer without configuration. Maybe browser based?? And it should work over USB.
I plan to use a USB to serial cable for the purpose.

Any advice would be greatly appreciated.

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Project section - "fboot" by "danni".

Make sure to get a USB-TTL not USB-RS232 for $2 on ebay then you won't need a MAX232.

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Quote:

I have been doing some searching for a bootloader for an ATMEGA8.

Side note: Why would anyone start a new app nowadays with the venerable Mega8? (Perhaps it is a one-off and there are already a few in the drawer? Fair enough.)

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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Oh, sorry, I meant its an 8-bit ATMEGA64

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Quote:

Oh, sorry, I meant its an 8-bit ATMEGA64


Now it gets more interesting...
Quote:

The actual Boot code needs to be <=256 bytes

The smallest bootloader partition size on a Mega64 is 512 words/1024 bytes.

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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The Fast & Tiny Bootloader has zero documentation, but appears not to program EEPROM. I need both FlASH and EEPROM programming.

In general the Fast & Tiny BL is what I'm looking for in that there is a simple GUI, that takes a file and then programs the device. I do not need all the interactive BL functionality that is out there.

I found a GUI version of Fast & Tiny Bootloader:
http://www.societyofrobots.com/a...
But there is no source code or documentation on it either.

My ATMEGA64 has a bootloader section as small as 256 words

Found TinySafeBoot: http://jtxp.org/tech/tinysafeboo...

Anyone have any feedback on it?

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Quote:

Anyone have any feedback on it?

But that's for Tiny AVRs not Mega (which have a properly protected BLS and the BOOTRST fuse)?!?

You appear to be trying to solve a problem you haven't got. The smallest bootloader for mega64 is 1K bytes - no point trying to squeeze a quart into a pint pot when you own a quart pot!

Quote:

My ATMEGA64 has a bootloader section as small as 256 words

Err no...

Attachment(s): 

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Look Closer, TSB supports Megas too.
The ATMEGA64C1 supports 256 words

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Quote:

The ATMEGA64C1 supports 256 words

But that's still 512 bytes - all the "popular" bootloaders like BLIPS, fboot, Optiboot, etc. will easily fit into that.

As for TSB it still does the unnecessary APPSTART offset thing on megas. When you have BOOTRST what would be the point. Sure TSB needs that on Tiny and when it ports to Mega it just inherits that Tiny technique but it is sub-optimal.

OTOH as long as its protocol is widely supported (avrdude especially) I guess it's going to be OK.

As for fboot lack of documentation:

http://www.mikrocontroller.net/a...

which Google offers to translate as:

http://translate.google.co.uk/tr...

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fboot apparently does not program EEPROM.

I'll look into the others you mentioned.

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megas cannot write to flash except from flash designated as the boot region, and this designation requires "fuse" setting.

As I recall.