Hi,
Some time ago I made my first arduino board, serial, single sided. Yet in the start it was showing some funny behaviour, as autoreset never realy worked as it should - it did autoreset arduino only from time to time.
Now (yesterday) I made to more boards for my friends, and noticed, that if I choose different board in arduino menu, different bootloader is burned. I think for mine I had board set to diecimilla, and now I set it to Arduino NG or older w/atmega 168.
So, both work, but diecimilla bootloader starts sketch much faster, is this normal? And also... I think autoreset works a bit better with second bootloader, but I have to ask: which it the right one for this arduino board?
I am using arduino 0012 Alpha, serial conection via COM1, and a parallel programer for burning bootloader.
I never used an atmega168 with Arduino Severino, but people who did it said it works, and people I know, is using diecimila bootloader, without problems. The timings are really different. If you use an atmega8, I suggest you to use Arduino NG or older w/atmega8.
Alternatively you can upload sketches, without the bootloader.
The bootloader used for the Burn Bootloader command is the only difference between the Diecimila and NG boards (I think). The NG didn't have an auto-reset, so the bootloader delay is much longer to give you time to press the upload button after pressing the reset button. The diecimila has auto-reset, so the bootloader timeout is much faster.
Yes, I am using atmega 168 on this board, an beside autoreset, it works nicely.
It's funny... when I have autoreset enabled, the led (on pin 13) blinks though, but it looks like it doesn't reset the board like it should. Has anyone contidered modifying the capacitor (just thought of it, no idea why)?
Ok, now I have spent some time testing... it's still quite random, if it works or not.
with older bootloader (big delay) it works, if not the first time...maybe the next. But when it starts working, it just works. Still, sometimes you'll just have to do it manualy.
With diecimilla bootloader it goes almost the same: when it's conected, autoreset won't work the first time usualy. But it's more likely (not necesarily) to work every next time until reset... but still, no real pattren of not-working :-/
I remembered another think related to Severino autoreset failure:
if the COM port speed is set to 9600 (windows default), it will not work properly. Set the COM port speed to 19200.
I read the manual... This was the first thing I did. And then I tryed all possible speeds, with no difference. Well with other speeds it didn't work at all
The building manual has an error, and if you made the board with the specified components on the manual with errors, perhaps the auto reset fail sometimes.
The 100nF capacitors are described as tantalum caps, but the correct is ceramic or polyester caps.
On my board I used a tantalum 10uF since I couldn't find a non polarized electrolyt (tryed with a polarised electrolyt though, but it didn't work), and polyester for 0,1uF. And of course electrolytic 100uF.