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Topic: Optiboot on various boards (Read 1 time) previous topic - next topic


I have just installed successfully the Optiboot bootloader on an Arduino Pro-Mini 5V.  I used Bill Westfield's Optifix sketch running on an Uno as the programmer.

Optifix contains a number of important bug-fixes not yet included in the official Optiboot package.  In fact the Optiboot project maintainer seems to have gone quiet.  I hope this excellent project will not fall into disrepair.

Bill, if you're reading this, could you be persuaded to publish the patched source that you used?  I would like to put Optiboot on some 3.3V Pro-Mini boards, and I think it will need to be recompiled to account for the 8MHz oscillator.  I would also like to experiment with including a readable version number.


My current optiboot.c and makefile are attached.   Note that for the version number to be readable from a sketch, you need to change the memory protection fuses to make the bootloader section "readable."

I'm not sure that the makefile is completely current, especially WRT to the *_isp targets;  I had difficulties getting atmega8 uploadable at the same time as 168/328 because of the missing EFUSE byte, and I was using an "optifix"-like utility to do my bootloader loading.  It's also set up for my local development environment and has some debugging additions.


Thanks for those.  I'll check them against the source version I'm using later today.

Meanwhile I have now got a patched Optiboot running on both 5V-16MHz and 3.3V-8Mhz Pro-Mini boards.  In order to get the 8MHz version working I needed to compile for a reduced upload baud rate.  The code includes your size-reduction patch and sketch amnesia patch.  I have also made the boot-loader readable and added a version number byte.

Now I need to do a bit of testing to check everything works as it should.  Does any kind of check-out sketch exist already?  If anybody else wants to try these bootloaders I'm happy to send them.  I'm using the excellent "optifix" sketch as an ISP, which is very easy to use and avoids the auto-reset problem.


Hi westfw,

Just built a board using optifix - ace program. The update you supplied in this thread is missing a few files:

#include "pin_defs.h"
#include "stk500.h"

and .c files for above.

Can you supply these or tell us where to locate them.

Many thanks

http://www.uk-pcb.co.uk - My UK Based PCB Fab & Assembly Company
Design work undertaken
SMD & Thru-Hole assembly


Drew, you can find the other source files on the Optiboot project page:

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