Overclocking an Arduino Duemilanove

I saw a youtube video on overclocking the arduino... i want to do this as well, but dont know the max... i plan to watercool it, so cooling is no issue... can i power the arduino to 3x origional(48mhz)? I plan to do a 6 oscillator setup... 8MHz, 16MHz, 24MHz, 32Mhz, 40MHz, 48MHz... i will wire it all up, it's just a matter of if the 40 and 48 will work... liek i said, if it's an issue of coolling, i have it all covered...

here is my source for all of this (btw, these are not my vids, all credit for them goes to inthebitz):

Build http://www.youtube.com/watch?v=ZPw1_22Ve7c

Pt. 1 [urlhttp://www.youtube.com/watch?v=-U-cc_Qcf-w][/url] Pt. 2 http://www.youtube.com/watch?v=5Peul80v2ec

Watercooling http://www.youtube.com/watch?v=4t-WHWAsyk0

I think there is a speed limit of how fast you can access the flash of the AVR. 32 MHz max.
Read this:
http://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&p=670372

I am not an overclocking expert, but I think liquid-cooling an AVR is a bit silly; the package isn't designed get get heat from the die to the outside of the package, so managing to get heat from the outside of the package to AWAY from the package isn't going to help very much. Sorta like putting ice outside your cooler and expecting your beer to get cold...

(unlike the pentium-class desktop cpus, where there has already been a LOT of effort applied to the path to get heat out of the chip...)

i want to do this as well, but dont know the max.

That is the whole point of over clocking you don’t know the max, you don’t know the effect it will have on the hardware and you will have to adjust the firmware at each clock rate you try because the communications and timers are all run of the system clock.

And after the effort what do you gain? It’s not like you want super smooth graphics or anything. If it is not running fast enough for you then simply re write the code.

Yes there is the curiosity aspect of doing this but if you are having to ask here I suspect that curiosity is not your main motivation.

In the video he said that he connected the batteries to the 3V3 connectors on the arduino. If he did that it would not work because that is an output derived from a regulator inside the USB / Serial bridge.

That is the whole point of over clocking you don't know the max, you don't know the effect it will have on the hardware and you will have to adjust the firmware at each clock rate you try because the communications and timers are all run of the system clock.

does that mean i could try it, but i might blow something? what would blow? the atmega 328 chip? because i could test it, and just have a spare handy...

Yes anything might be damaged but it would only be from heat. Cooling doesn’t always work because of the thermal resistance between the chip and ambient. You can have in effect an infinite heat sink and still blow a chip because of heat.

However, thinking about the way he said he wired it up makes me think the whole thing is a hoax.

However, thinking about the way he said he wired it up makes me think the whole thing is a hoax.

i see what you mean, but he plugged the 3.3v from the lythium backpack into the 5v supply in on the board... or is that the 5v output? idk... anyways, i would have 5v from the usb...

but he plugged the 3.3v from the lythium backpack into the 5v supply in on the board

But that is not what he said, he even drew 3.3V on the paper next to it.

he even drew 3.3V on the paper next to it

yeah, he took 3.3v and put it into the 5 volts in ont he arduino... he basically underpowered the arduino...

anyways, i wanna try this... i found the oscillator i wanna use... these are the links...

16 MHz: http://www.mouser.com/search/ProductDetail.aspx?R=695-HC49US-16-U Catalog Page: http://www.mouser.com/catalog/catalogUSD/641/905.pdf

all of the other values have the same specs as the 16 MHz, but just different frequencies... i just dont know if the capacatince is correct, the oscillators have 18pF, and idk what the board has stock... please reply

Yes that is a crystal not a crystal oscillator. The sort of thing I think was used was a crystal and oscillator in one package. Like this :- http://gb.mouser.com/ProductDetail/Vishay-Dale/XO52CTFLNA32M/?qs=sGAEpiMZZMsBj6bBr9Q9abZYj8j%252bUoOKClj%252bWiuuLqY%3d The point about using an oscillator rather than a crystal is that the chip will not even drive a 16MHz crystal at 3V3, so in effect he is taking the oscillator part out of the equation.

Don't worry too much about the capacitance, it is only really important for getting an accurate frequency and you are in a definite "don't care" with this project.

Grumpy_Mike:

Is it possible to use just a crystal (plus some caps, I would imagine?) instead of a resonator to run the ATMega - or must you use an crystal oscillator? Just kinda curious because I bought a few crystals (not oscillators) for future use on ATMega chips - but should I have bought the oscillators instead (or should I just go with resonators)? Its not a big deal, as I bought these surplus and maybe spent a $1.00 for 5 of them...

:)

The normal Arduinos use a plain crystal. A actual external oscillator can be useful for overclocking, because sometimes the first thing that stops working as you try to overclock a microcontroller is the (internal) crystal support…

i found a new line of oscillators... is theyre the wrong ones, can somebody find the right ones? i need 16, 24, 32, 40, and 48Mhz

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=644-1037-1-ND

found a new line of oscillators...

I'm afraid that is not an oscillator, it's just a crystal, with two terminals. An oscillator (that will contain an internal crystal) has at least three active pins, ground, power, and signal output.

Lefty

ok... im at a brick wall here... idk what voltage to look for or anything... can i use the 3.3v and gnd from the arduino rails, and just have the signal wire go to the oscillator... also, which pin is the signal? as in the usb side, or the reset button side?

well... i guess this is just another project that failed... oh well..

If you just want to blow things up, get some fireworks.

Can't do that in AZ: they're illegal here because almost the entire state is under "high fire danger" warning about 330 days per year.

If you want to destroy things here, the proper way to do it is to take them out into the desert and shoot them :)

maybe i can do that with my bro's glock next time we go shooting... hmm...