💬 Various bootloader files based on Optiboot 6.2

[Samuel235]

@alexsh1 If you haven't touched the ATmega328p then it should be sitting with fuses of; L:0x62 H:0xD9 E:0xFF, which would run the uC at 1MHz

[GertSanders]

@*alexsh1
*
Which fuses are set when loading a boot loader is defined by wich menu element in tools you have selected. Every processor or board you choose will correspond with values in a board.txt file.

You can have several board.txt files: 1 file per "family" of boards.

When uploading sketches, the fusesettings are ignored, only the uploadspeed counts then. Both when uploading with Arduino as ISP as with FTDI interface.

The internal oscillator of 8 Mhz is not as accurate as a crystal, so at higher uploadspeeds the errorrate can increase or decrease depending on the mcu temperature.

Some uploadspeeds are closer to optimal then others in relation to the frequency at which the mcu works. The baudcalculator shows the errorrates. Most are non optimal. avrdude can handle an errorrate of 2% or less. So using a specific baudrate in combination with the internal 8Mhz oscillator depends on the worst case combination of transmission errorrate plus clock deviation error.

For most mcu's the rate of 9600 baud will be acceptable because at that slow rate a clockerror will be relative small. At higher speeds the small clockerror becomes more important. Then it is best to choose an upload speed close to the optimum.

The fusesettings are only burnt when loading a boot loader (within the Arduino IDE, in AVRStudio you can set fuses seperatly from loading anything).

The frequency of 8 Mhz can be obtained via a 8mhz crystal or the internal 8mhz oscillator. The low fuse value 0xE2 sets this internal oscillator. By using value 0x62 you also set the clock division bit in combination with the 8mhz internal oscillator, so your mcu will run at 8mhz / 8 = 1mhz

There are other division values possible. Calculate the low byte value using an avr fuse calculator.

You can also use an external 8 mhz crystal, and combine this with clock division by 8 to get 1mhz operation.

And you can choose an external 1mhz crystal.

All this from choose the right fuse bits.

Same for Brown out Detection which is set via the three least significant bits of the extended fuse.

[alexsh1]

@samuel235 This is strange. The serial monitor was working only on 74880 - I do not think the AVR was running @ 1Mhz

[alexsh1]

@GertSanders Thanks for a detailed write-up!

@GertSanders said:

You can also use an external 8 mhz crystal, and combine this with clock division by 8 to get 1mhz operation.

And you can choose an external 1mhz crystal.

How is this influencing low power though? My understanding is that such setup (external crystal) takes more power.

[GertSanders]

@alexsh1

Using a 1mhz crystal would not be the best thing for low power use, you are correct there.

But it gives a more accurate clock base for the timing functions.

[alexsh1]

Not sure what happened, but the following error returned:

Board atmega328p:avr:atmega328pO5M8c doesn't define a 'build.board' preference. Auto-set to: AVR_ATMEGA328PO5M8C
Board atmega328p:avr:atmega328pO5M16c doesn't define a 'build.board' preference. Auto-set to: AVR_ATMEGA328PO5M16C

I did not change anything so very strange why it comes up.

[Samuel235]

Actually, i have no proof but i've been informed from the arduino standalone microcontroller forums, that using a external 8mhz crystal is good for power consumption. ONLY if its a sleeping module though, it enables it to perform its tasks quicker and then sleep quicker, resulting in more time sleeping.

That error code is something i ran into, i'm guessing you're working inside of arduino IDE, if so its to do with your boards.txt entry. Its missing that entry that it speak about. Check that its there, if not enter it in manually.

[alexsh1]

@samuel235

Thanks - yes you are right it is about boards.txt.
However, the problem is that I did not change anything. Two days ago I uploaded severa sketches and no errors were coming up and now two different boards are showing the same error. This is just odd...

[Samuel235]

@alexsh1, have you performed an Arduino IDE update? I had this exact issue simply because I updated my IDE.

[GertSanders]

This message pops up since IDE 1.6.7
The new IDE expects this entry for all boards, just add it or ignore (it's more a warning then an error).

[Samuel235]

And there you go, the forever informative @GertSanders has andwered your questioning ;)

[alexsh1]

@samuel235 Looks like you are right - without realising I did press update button thinking about a sketch rather than about the update :(

Corrected this issue aleady in the boards.txt

[carlierd]

@GertSanders Hello ! I am trying to upload a sketch without success for the moment.

Burning of the bootloader was done correctly (led on pin 8 lit three times) but impossible to load a sketch.

For easy deployment I choose to create a new folder to include your bootloaders:

But it seems that something is missing as upload is not possible:

Le croquis utilise 1 030 octets (3%) de l'espace de stockage de programmes. Le maximum est de 32 256 octets.
Les variables globales utilisent 9 octets (0%) de mémoire dynamique, ce qui laisse 2 039 octets pour les variables locales. Le maximum est de 2 048 octets.
/Applications/Arduino.app/Contents/Java/hardware/tools/avr/bin/avrdude -C/Applications/Arduino.app/Contents/Java/hardware/tools/avr/etc/avrdude.conf -v -patmega328p -carduino -P/dev/cu.usbmodem1411 -b38400 -D -Uflash:w:/var/folders/2y/_n7gfzjx5_sgmtyh9t_lp0wc0000gn/T/build8919458311701309495.tmp/Blink.cpp.hex:i 

avrdude: Version 6.0.1, compiled on Apr 14 2015 at 16:30:25
         Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
         Copyright (c) 2007-2009 Joerg Wunsch

         System wide configuration file is "/Applications/Arduino.app/Contents/Java/hardware/tools/avr/etc/avrdude.conf"
         User configuration file is "/Users/carlierd/.avrduderc"
         User configuration file does not exist or is not a regular file, skipping

         Using Port                    : /dev/cu.usbmodem1411
         Using Programmer              : arduino
         Overriding Baud Rate          : 38400
avrdude: ser_open(): can't open device "/dev/cu.usbmodem1411": No such file or directory
ioctl("TIOCMGET"): Inappropriate ioctl for device

avrdude done.  Thank you.

Problème de téléversement vers la carte. Voir http://www.arduino.cc/en/Guide/Troubleshooting#upload pour suggestions.

Any suggestion ?

David.

[GertSanders]

@carlierd
I am almost certain that you are NOT using my boards.txt because you put the bootloaders outside the reach of the IDE (must be in the sketchfolder and within the hardware subfolder of the sketches folder).

[carlierd]

@GertSanders
No doubt that I using your file as I got the same problem as @alexsh1 with the arduino pin file.

Look at my board choice:

I find this method very good for deployment but only when it's working ;)

I check the bootloader with Nick Gammon sketch and it seems good.
David.

[carlierd]

I burn the bootloader one more time and now I can upload without any change on configuration.

Perhaps I made a mistake the first time :)

I will continue my test.

David.

[carlierd]

@GertSanders One more question on the LED connected on B0.

When you wrote that the LED lit on arduino reset, it's when the reset button is pushed ? when the arduino start ? or both ?

David.

[GertSanders]

@carlierd

When the atmega328 is reset, the LED will flash three times if the boot loader is in memory. This also happens when you send a new sketch via the Arduino IDE to the atmega328.

So if you connect pin 1 shortly to GND, the led should flash.

The first time you load a boot loader, the atmega328 will "loop" between the startup procedure of the boot loader (and will flash the led), and then try to load the sketch. If there never is a sketch, it will start the boot loader again and again ...

[carlierd]

@GertSanders

So it confirms that your bootloader was correctly burnt in the atmega as the first time I failed to upload a sketch the LED flash three time again and again !
Thanks !

David.

[carlierd]

Hello,

I tested two bootloaders today:

• optiboot_atmega328_08M_038400_B0.hex
• optiboot_atmega328_01M_009600_B0.hex

But I am pretty sure you already tested them.

I got some issue with 1MHz bootloader but probably because I am using signing feature.
I will check the forum to be sure.

David.