After a years-long wait, an ARM powered Arduino is finally due. The Arduino Due will finally be released this coming Monday.
On board the Arduino Due is an Atmel-sourced ARM Cortex M3 microcontroller running at 84 MHz. The Due has an impressive list of features including a USB 2.0 host, compatibility with the Android ADK (lest you still need an IOIO), 12 analog inputs with 12-bit resolution, 2 analog outputs running at 12 bits, a CAN interface, and more input pins than you can shake a stick at.
For a full list of features, you can grab this PDF we picked up when we saw the Due at Maker Faire NYC
This hardware update to the Arduino platform makes a lot of very cool builds very possible for even the beginner hardware hacker. Of course the Due will be used for controlling drones and UAVs, laser cutters and 3D printers, and playing WAV files from the analog outputs. The much improved hardware opens up a lot of other possible builds including making your own guitar pedals – DSP is a wonderful thing – and reading the telemetry from your car in real-time via the CAN bus.
Although it’s not available right now, you will be able to buy an Arduino Due for $49 USD this coming Monday at your favorite electronics retailers.
3.3v operating voltage.. Does this mean ‘HIGH’ is 3.3v? :(
We demand answers to this!
*Record scratching sound*
The Due will continue to work with all Arduino shields — add-on boards and circuitry like motion sensors and LED light arrays — that conform to the official Arduino Revision 3 layout. However, the Due operates at 3.3V whereas AVR-based Arduinos operate at 5V, meaning some third-party shields that don’t follow the R3 specs to the letter may not be compatible, depending on their voltages. It also means those looking to use the Due in existing applications should adjust their voltage or risk damaging their board.
Some third party? You mean, pretty much all of them?
Yes. They mean pretty much all of them. But not to worry, official Arduino Revision 3 layout has been on display for months! You could of filed a complaint if you wanted to, they were “displayed” in a locked file cabinet in the dark basement of the local planning office!
Yes – logic 1 (positive logic) is == VCC.
You can use a variety of voltage level sifters, such as a 74HC06 (which has the disadvantage of also inverting the signal, but has open-collector outputs).
Besides, the ARM (in most cases) can sink/source only small amounts of current per pin, so buffering the signals is a good idea.
The Ruggeduino
The Ruggeduino is a ruggedized Arduino-compatible microcontroller board. Features include overcurrent and overvoltage protection on all I/O pins and 5V/3.3V outputs, ESD protection on all I/O pins and USB port, total microcontroller overcurrent protection, and operation at up to 24V. Fully assembled and ready to work right out of the box. Works with the Arduino GUI and is compatible with Arduino shields and libraries.
There needs to be a DUE version of this, stat!
@Hack Man:
The STMicros STF1xx/2xx ARM series have 5V tolerant input pins. I suspect most ARM chips have the same (this is a guess), and not to argue with what you said (Thanks for the info!).
The problem comes when trying to drive a 5V output with a 3.3 out pin. That is when you need a buffer. There are many in the 74xx TTL and 4000 CMOS line – and you get the ability to drive more current than the pin can drive itself. Depending on switching speed, you could even use a unity-gain opamp, but most have a very slow switching time (and the fast ones can be spendy).
You made this very point about some shields that expect 5V inputs not working with this board.
You really don’t want to use a unity gain opamp to level shift GPIO.
The problem with a unity gain opamp is that it is “unity gain”, meaning 3.3v in, 3.3v out.
There are other problems with this configuration, namely problems with rail to rail output stages and saturation recovery time.
@Ken:
The comment about using a unity-gain on a GPIO was a bit :^) – and after I mentioned it, I realized it could confuse the unwary and those new to the game.
Mea Culpa
For individual pins, converting from 3.3 to 5V with a good load: there are good FET circuits out there. For several pins, use a 74xx or (better) 4000 series buffer – just be sure to look on the datasheet to see what a “1” input is relative to VCC. (see the 74F06 as an example)
Perhaps @Ken could provide a link to a good FET circuit – I only play EE on TV; I suspect Ken are one…
I would recommend against using 4000 series CMOS parts. They are being increasingly harder to find and are very slow.
Use 74HCT parts. They are cheap, available, and can maintain good worse case VOH and VOL values under their rated load.
If you can get them for cheap, 74AHCT parts are even better.
@Ken: Thank you for the clarification – my basic point was the ARM is CMOS logic, so the interface logic should also be CMOS, not TTL.
The “CMOS cookbook” by Don Lancaster is a good reference. A bit spendy ($40 on amazon). Also, lots of good stuff via Google…