ATmega644P vs. ATmega1284P

I bought a used kit that came with a sanguinololu with an ATmega644P. I've seen a lot of discussion about boards with ATmega1284P and I'm assuming it's newer/better/faster. But in a reprap (prusa2) what difference would I really see? Is it worth an upgrade? I assume I could just head to ebay and buy an ATmega1284P and swap it in the socket where the 644p is?

Thanks for the input. -Bret

Besides a few unused features, the 1284P has more flash memory, so you can upload bigger sketches. Anything else, packaging, pinout and even speed is exactly the same. Accordingly, upgrades make only sense if your choice of firmware doesn't fit into the 62k ( + 2k for the bootloader) of the 644P.

When purchasing an ATmega, be aware you either have to get one with a bootloader preloaded or to additionally get a programming device. Factory fresh ATmegas don't communicate over the serial line.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

Thanks Traumflug. I was planning to use Marlin with the SD card attachment (but not the LCD panel stuff). Hopefully it compiles into somethign small enough to fit. If not, I may switch to something else.

Really good to know about the bootloader issue. That woudl be an unpleasant surprise as I don't have anything currently that will let me program a blank like that. Looks like there are some good approaches listed on the forum, but I'd rather avoid that if possible so I'll see if I can keep it to under 62K.

On a different topic, why is the firmware called a "sketch"? (I guess it's really anything loaded with arduino) I found that term rather confusing when building a 3d printer because I think of the STL file or the G-code like more of a sketch but that doesn't go into the flash of the ATmega, that's on the host computer and/or the SD card.

Thanks for the helpful tips.

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On a different topic, why is the firmware called a "sketch"?

Because the Arduino folks choosed this name It's plain C or C++, supported by the library coming with this IDE. That's all.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY