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Topic: Working on a 69 I/O Pin Megaduino. (Read 4049 times) previous topic - next topic


Dec 29, 2008, 03:34 am Last Edit: Dec 29, 2008, 06:39 pm by FlickerShow Reason: 1
I've looking up on how to make a dev board and with the help of a friend who's in his third year as an electrical engineering major, I'd like to make a board to be the big brother to the Arduino, and even the Sanguino. I'll be designing my own PCBs, and if the big kahuna is SMD I'll make a special board with pins on the bottom to keep that modular usefulness.

My actual question is this: What is the largest chip out there (DIP or not)  from Atmel that can hold the bootloader and work with the arduino programming environment?


The ATmega168 is the stock Atmel chip on Arduino platforms, and is the most capable that is supported.  Several people have done the legwork in preparation for wide availability of the new Atmel ATmega328 chip, only a few of which have been distributed.  I don't know of any other larger microcontroller (Atmel or otherwise) that has any support by the Arduino bootloader scheme.  It is this bootloader that makes it an Arduino, more than any other aspect of the board.


Well seein gas the Sanguino runs off of an Atmega 644, and I've heard talk of something like an Atmega 1268, I think there may be something larger.

If I need an altered bootloader, my roommate's a sophomore software engineer (gotta love having equally nerdy friends).

Anybody have any suggestions?


I think I've found my big fish, now it's time to start working with it. If anybody has any interets in the project, let me know and I'll keep you in the loop.


Dec 29, 2008, 07:15 am Last Edit: Dec 29, 2008, 07:16 am by retrolefty Reason: 1
"If anybody has any interets in the project, let me know and I'll keep you in the loop. "

Well many of us would be interested in hearing about progress. And software room mate or not, I'm sure there will be questions to come up that others around here have worked through already. So just keep posting in this thread on progress.

So what is the big fish you have in mind ;) Bet it has a lot of fins..er I/O pins.



Dec 29, 2008, 06:00 pm Last Edit: Dec 29, 2008, 06:03 pm by FlickerShow Reason: 1
Ive poked around Atmel's site a bit further, and thi largest chip in the ATMEGA168's class is the ATMEGA3250. It has a similar internal structure to the 168and should be prodded into functioning with the same software (relatively) easily.

You asked about I/O pins? There's a whopping 69 of them, and I'm still reading the 375 page datasheet for further details, like PWM capabilities. There are (if I'm reading this correctly) four PWM-ready pins, with more available through some witchcraft.

In terms of on-board memory, it offers up 32K of flash memory, 1K of EEPROM, and 2K of SRAM.

I'll definitely want to push out all of it's pins, not for my own purposes (not sure I'll ever need that many), but for others who may want a try at maxing even this guy out.

I may try short ribbon cables leading out to individual male pins, to allow people to pull them out of a breadboard sequentially, so as not to strain the entire board by lifting all pins at once, connected to the same board. I might put on some female headers, and group similar pins to the Arduino's in the same spots relative to each other, so that all your old shields will still fit, with some new programming of course.

If anybody can think of any features they'd want put them up. This project will probably take a while to complete, so I'll take my time adding boukou features.

Here's the 3250P's datasheet for some light, 325 page bedside reading. http://www.atmel.com/dyn/resources/prod_documents/doc8023.pdf


You may want to take some cues from the Wiring board, which was before Arduino and had 49 I/O pins, using the Atmega128 with 128KB flash and 8KB RAM.. There is a version of the 128 that has 100 I/O pins, I don't know if Wiring supported it.
Unique RGB LED Modules and Arduino shields: http://www.macetech.com/store


Biggest DIP AVR is the 644p. Check out Sanguino.cc. I've designed and built a variant of that. If I can do it, anyone can ;->

If you SMD is what you mean, check out "Wiring". Uses the Atmega 128. There's a link to it on the arduino home page I think.

And if you want the VERY BIGGEST, I think there's an Atmega 2561 in a 100 pin package ...


Well the hong is that the ATMEGA3250 is indeed a 100pin package, but 69 I was referring to meant the general purpose I/O pins. I'm working with a friend ok this, but as this is a learning experience, I'll probably be checking in periodically.


Jan 01, 2009, 04:30 am Last Edit: Jan 01, 2009, 04:35 am by Ro-Bot-X Reason: 1
What about the ATmega640/1280/2560? It is SMD, has 100 pins (TQFP), 4 UARTS, 12PWM channels, 16 analog pins, 64k/128k/256k flash, 8k sram, 4k eeprom... Need I say more? Oh, there is a board that uses ATmega640 (not all of the pins are brought out), it is called the Axon and is robot ready!


And then there's the xmega128a1 .... ;->


Xmega would provide the extra gimmick I need to sit up and take notice.
Unique RGB LED Modules and Arduino shields: http://www.macetech.com/store



Yep; still vapor.  Mouser isn't expecting their order to show up till 4/1.


This is pretty typical of Atmel when releasing a new and very different AVR... it's always expected in about 3 to 4 months.

In September I was told the xmega was expected around December to January.  At the time, I found several older press releases that said it was expected around Q2 2008, which had already passed.

I'm sure they will eventually release it.  I just wouldn't hold my breath!

Thinking of vapor, how does a Teensy ( http://www.pjrc.com/teensy/ ) with 46 I/O pins for $25 sound?  ... by the end of January.

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