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I found an LCD for my Arduino Mega 2560 that's parallel (I like that, I don't like SPI), but it works at 3.3V and isn't 5V tolerant. That's why I'd need to use level shifters, but that would use too much space and I'd like to power the microcontroller with 3.3V. But that would cause problems because the USART communication is set to be on 5V and that can't be changed.

Is there a way to power my Arduino at 3.3V? Is there an alternative Arduino for that?

Also, if there is, I'd need to have a 16MHz crystal on it. I know it's overclocking, but Gamebuino works at 16MHz on 3.3V and I would like to do the same.

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    Maybe a Due would be more suitable for you...? – Majenko Oct 17 '15 at 14:01
  • You can use pro mini 3.3v and one shift register. It is not SPI :) – Mert Gülsoy Oct 17 '15 at 14:29
  • Some of the smaller boards may not have enough I/Os. Typically the ARM-based boards are native 3.3v, with more memory and faster too. Level shifting the serial shouldn't be too hard. – Chris Stratton Oct 17 '15 at 15:21
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    It must be ATMEGA2560 because of the pin count and XMEM for the display. My project is to make an 8-bit AVR game console with most RAM as possible and a fast LCD. It's something like those NTSC projects, but mine is a handheld console. If I have to, I can work in full ASM. – Foxcat385 Oct 17 '15 at 16:31
  • SPI into a shift-register is pretty fast. If space is a premium I would have thought that the Mega2560 board was a little large. – Nick Gammon Nov 19 '15 at 4:13
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Have you considered maybe using the Iteaduino MEGA2560?

The Iteaduino MEGA2560 uses the same ATmega2560 processor as the Arduino Mega 2560, but is physically much smaller, the size of a Arduino UNO. It has a switch to run the ATmega2560 at 3.3 V, so its I/O pins can be directly connected to 3.3 V modules. It breaks out all the GPIO pins of the ATmega2560, so it actually has more I/O on its connectors than the Arduino Mega 2560.

If I'm reading this right, the Iteaduino schematics and a typical Iteaduino features list seems to say it already has a 16 MHz crystal.

  • Can I connect an external 16MHz crystal there? – Foxcat385 Nov 18 '15 at 21:16
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Have you considered maybe using the "Sparkfun Mega Pro 3.3V" plus a "SparkFun FTDI Basic Breakout - 3.3V" ?

It uses the same ATmega2560 processor and has the same I/O arrangement as the Arduino Mega 2560, but it runs off 3.3 V. It doesn't have the 16 MHz crystal you wanted, but if you really insist on overclocking, perhaps you could replace its 8MHz resonator with a 16 MHz crystal?

Sparkfun Mega Pro with resonator circled

  • I don't see where the resonator is. I don't see the pin to connect it to either. Can you show me? – Foxcat385 Nov 18 '15 at 21:11
  • Does that doodle on a photo answer your question? – David Cary Nov 19 '15 at 4:24
  • I see. I hope that I won't damage it or the MCU while unsoldering. What kind of a soldering device should be used there? – Foxcat385 Nov 19 '15 at 11:23
  • Wide chisel tip soldering iron with a big blob of solder to take it off the board. Soldering braid to clean up the pads. Narrow fine-tip soldering iron to attach new parts to the pads. A better place to ask questions about soldering techniques: electronics.stackexchange.com/questions/tagged/soldering . – David Cary Nov 19 '15 at 14:41
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Have you considered maybe using the ElecFreaks Freaduino MEGA2560 ?

It has an identical I/O arrangement and dimensions as the Arduino Mega 2560 -- including the ATmega2560 processor. It has a selector to run the ATmega2560 at 3.3 V, so its I/O pins can be directly connected to 3.3 V modules. The voltage regulators and reset switch position are better than the Arduino Mega 2560.

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Have you considered maybe using the Inhaos Buono Mega 2560 (see a), also called the Inhaos Mega2560?

As far as I can tell, it is pretty much identical hardware as the Arduino Mega 2560 -- including the ATmega2560 processor -- except it has a selector to run the ATmega2560 at 3.3 V, so its I/O pins can be directly connected to 3.3 V modules.

Like many websites, every page on the Inhaos website http://www.inhaos.com/ has a "Contact Us" link at the top of each page. Click that link to get a list of several ways to contact the company.

  • This one is the best, but unfortunately, it's no longer for sale. Is there a way to buy it somewhere or to contact the company? – Foxcat385 Nov 18 '15 at 21:36
  • As far as I can tell, the "Inhaos Mega2560" is still for sale. I added more links to this answer; does that answer your question? – David Cary Nov 19 '15 at 14:24
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What about a 3.3v Arduino Pro Mini, you'll need to solder headers but that's not too onerous. See here Arduino pro Mini or even cheaper from eBay

  • Is there a 2560 version of that? – Foxcat385 Oct 17 '15 at 16:32
  • Not that I'm aware of. What's the 2560 specific functionality that you require? – Bra1n Oct 17 '15 at 16:35
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    XMEM access to external RAM and the display for super speed. It's for my 8-bit handheld console project with maximum RAM and fastest color display. – Foxcat385 Oct 17 '15 at 17:10

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