Is this good for us ATmega1284P ?

I was looking into the Sanguino and was intrigued to notice the ATmega1284P [www.atmel.com] which has more RAM, more flash memory and more EEPROM then the ATmega644P but seems otherwise the same. I found some discussion at the Arduino board [www.arduino.cc] [www.arduino.cc] but I couldn't find any here so I thought I'd mention it.

From what I can tell (not being an EE or having experiece with microcontrollers), it's basically a drop in replacement for the ATmega644P. At least the pinout seems the same other then the PCINT24/RXD0 pin also functioning for the second 16bit timer. And it doesn't seem to have any other significant differences.

Am I right then that you could basically pull out the ATmega644P* and stick the ATmega1284P into the same board and it should work fine**? (Of course you doneed to program the chip.) Indeed even the software I presume wouldn't need much or any work, perhaps just recompilation. (Obviously to take advantage of the extra RAM and stuff you'd have to change something.) In other words, this should be much less painful change then even from the Arduino to the Sanguino which required a new circuit board and stuff and did need some minor code changes. Sorta the way upgrading just the CPU on your comp should work.

My second question is this part actually likely to be useful for us? Are we likely to gain from the more RAM and perhaps larger flash or are we more likely to hit problems because of the processor speed or the lack of IO pins first or at around the same time?

*Unless you happened to solder you ATmega644P in which case you're going to have to desolder it first. But if you did that I guess you're good at soldering so it doesn't matter...
**Of course if you didn't power off your board before pulling out the chip, you may actually need a whole new board including components...

Edited 1 time(s). Last edit at 01/11/2009 01:53PM by Nil Einne.

BTW. whatever the case, before you get too excited bear in mind the part isn't actually easy to get hold of yet. According to the second Arguino forum link, the chip has production delays and DIP part may be delayed further. And these site say sampling in 2009Q1 [www.nabble.com] [www.avrfreaks.net] (AVRfreaks suggest it's been delayed a lot so don't count on this date).

If you try to order from Digikey [search.digikey.com], you'd find if you order 290 or a multiple thereof, they should ship around 8/3/2009 (for American's that's 8th March) so perhaps if you have US$1,388.81 + shipping to spare you could order some and hope they actually arrive in March :-P (Actually if you check the Nabble link it seems the minimum order in Digikey has come down since the end of last year.)

If not, you may be able to get some non-DIP ones (probably TQ44) either if you have the right contacts (again see AVRfreaks link) or try buying a Raven [en.wikipedia.org] and desoldering the chip [www.avrfreaks.net] ;-)

Of course you could just save the money and wait until they are actually widely available and instead donate a RepRap to someone needy ;-P

This site lists them at $3.80. They're out of stock, though.

[www.ezpcb.com]

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Hell, there are no rules here - we're trying to accomplish something.

Opportunity is missed by most people because it is dressed in overalls and looks like work.

Thomas A. Edison

Heck if they are pin compatable, it's an easy upgrade as our Sanguino's have sockets!

freds Wrote:
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> Heck if they are pin compatable, it's an easy
> upgrade as our Sanguino's have sockets!

That's what I'm thinking. But they don't actually seem to say they're pin compatible even though I can't see any reason why they're not but I don't know enough to say for sure.