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Support Forum » Downgrading The ATmega168 To Save A Buck

August 19, 2009
by Nerdful_com
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Let's say I had an ISP and a product I prototyped that did a simple thing like LED effects and some noises and knew I didn't need as much RAM, could I simply down grade the chip a bit to say a ATmega8, ATmega88, ATmega32 or a ATmega644 without changing the bootloader?

As far as I can tell they all have the same pins (see here for Atmel chip comparisons or info about bootloader).

Thanks from Nerdful.

August 19, 2009
by mrobbins
(NerdKits Staff)

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Hi Nerdful,

The bootloader might need some small modifications, but yes, in principle you could.

Additionally, you can look at even smaller version of the AVR series that don't have any bootloader at all, such as the ATtiny261 with 128 bytes of RAM. You don't really need a bootloader if you are making a "finished product" that the user doesn't need to be able to reprogram. You then need to use an ISP programmer for programming each of the chips, and would just load your program -- no bootloader at all. For example, DigiKey sells the ATtiny261 in quantity 100 for $1.18 each.

Hope that helps!

Mike

August 19, 2009
by Nerdful_com
Nerdful_com's Avatar

Thanks, good to know. When the time comes (I am still a newbie with big ideas) I guess I will ahve to figure out what will be needing changes and then repost here to "kind of" follow up with a "what to do" post.

Also thanks for data about the ATiny, that's what I see used in many hobby kits (like the MinyPOV) that are under $20 and already come preprogrammed.

March 26, 2012
by foxegg
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Same issue here... Can anyone advise how I can change the makefile code for the ATmega8 (which I bought when I was having problems)

It is a pin out equivalent for the ATmega168 but when I run 'make'.. it just doesn't program the chip (I foolishly thought that it would be that easy to plug out plug in)

So I have looked around but if someone more knowledgeable can direct me, I would be grateful.

...and I thought the 8 was a later version ! doh !

Foxegg

March 26, 2012
by Ralphxyz
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Don't you need to use a ISP (Inline Serial Programmer) to program the ATmega8 or did you put a bootloader onto the ATmega8?

Using ISP you do not need to use a makefile as you precompile the program and just transfer the .hex to the ATmeg8 using ISP.

Theoretically speaking of course as I have never done this but I do have some ATmega8's that I have never gotten around to programming.

And of course you would need to pre-compile the code needing a Makefile.

Ralph

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