No mega649p

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It looks like there will never be an Atmega649p. I'm probably the only one who wanted to use it, so that could explain why Atmel dropped it.

They used to have it listed on their site and I have the migration document, but no more. Digikey used to list it with a ship date estimate of 01/27/2007 and the note "Delivery Date Past Due". But it's no longer listed.

I think I will survive this disastrous turn of events though. So far all my code will fit into a mega329p and if it doesn't in the future there is always the mega649 (without the p).

It surprises me actually. I assumed all the non pico power chips would be superseded with the pico power ones. Apparently they made an exception for this chip, probably because Atmel doesn't like me. :)

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Can you upload the datasheet for it, I'm curious what exactly it was.

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I don't have the data sheet. I do have AVR509: Migration between ATmega169p, ATmega329P and ATmega649P.

But I can tell you what it would be, if it existed. A low power version of the 649. The 649 is identical to the 329 except it has more ROM and RAM. And the 329 is identical to the 169 that is on the Butterfly board, with two exceptions. More ROM and RAM, and the pin change interrupt enable and flag bits are shifted two positions in their registers. (PCIE1, PCIE0, PCIF1 and PCIF0).

I run the same code in the 329p and the 649. The 329p draws 3 uA in power-save and the 649 draws 8 uA. That's with timer2 running, driven by the watch crystal oscillator, and the LCD disabled. Otherwise they are all the same to me. And if the software will fit, I run it also in the 169 and 169p.

For instance I have Dean's Buttload program running in a 649 right now, even though it was written for the 169. I did have to change two lines of code because of the aforementioned pin change bits. By flipping the bit in both the old and new bit positions, the same hex file will run on all the xx9 chips.