Arduino Two: First Impressions and new features

After months of waiting, the long-awaited Arduino Two is finally here 🙂

I have not yet had the opportunity to have it in my hands, but looking around in the network and specially in the official site, in this article i want to highlight the main news of this system compared to its predecessor Arduino UNO.
Well, what to say!
On the paper, the news are actually many and all derives from the new Atmel SAM3X8E CPU Cortex M3 with 32bits ARM architecture that replaces the old 8bits AVR:
1 – CPU Clock at 84Mhz (16Mhz compared to the previous version)
2 – 96Kb of RAM (compared to 2Kb)
3 – 512Kb of Flash (UNO had 32Kb)
4 – 12bits PWM and analog inputs (compared to 8bits)
5 – Output DAC – New for Arduino
6 – Higher number of PIN
7 – USB Host

Tis means an extremely higher processing speed, accuracy greatly improved and new possibilities thanks to the DAC and the USB host.

Performances are mainly related to the clock speed coupled with the 32bits (and of course more RAM).
With 32bit we are able to perform a 4bytes operation (8 x 4 = 32) with a single CPU clock. This means in an empirical way, that Arduino TWO might be about 20 times faster than Arduino UNO.

The most accuracy is related to the 12-bits analog inputs and PWM outputs: we have 16 times the old resolution, that means we have 4096 levels of conversion from analog to digital and vice versa compared to the 256 of the previous version. This allows a higher density of input data and a greater control on the PWM output.

The new features mainly concern the DAC pin (analog outputs, that is linear from 0 to 3.3 V) allowing for example to perform a MP3 file and hear it on the speakers connected to these outputs.

The only negative notes in my opinion (you have to be really picky though!), are the lack of an ethernet port – now essential in any application, and the fact that the TTL is 3.3V and not compatible 5V; with the wrong voltage you will fry pin or microcontroller itself. This leads to an incomplete compatibility with the existing shield or with third-party hardware.

Regarding consumption theoretically should be similar Arduino Mega although I did not find anything specific about it.

The programming instead always work through our Arduino IDE, updated to version 1.5 for the occasion, which contains additional libraries for the management of the new capabilities of the board. The programming mode is very similar to the old procedure.

Obviously, in this article we talked about a version out a few days ago and still in the testing phase. Time will tell if this card will completely replace the old Arduino, or if there will be a parallel market that will adapt depending on the final application. Surely those news lead further innovation in this field, such as to suggest that now the Arduino product may encroach further from the world of “geeks home” in the electronics professional.
Certainly a product like Arduino DUE, in terms of performance and precision is a product that is well suited for applications beyond entertainment home at a very attractive price (Arduino Store official price: Euro 39).
On the other hand, with this platform, it will be difficult to create embedded designs similar to those achieved with ATtiny85 or ATmega328 in standalone mode, but you can of course continue to use the old AVRs: as I said before, depending on the final application, you will find the best solution.

About Time will … See you next post!

Arduino Standalone (Arduino without Arduino)

In this post I will show how to use Arduino in a standalone configuration, ie use the ATmega328 (equipped with a bootloader) in circuit without having to lug around all our Arduino Uno (or the board you have).
The concept is this: I have finished protyping my project with Arduino (such as a RGB Led Lamp) and I’m ready to make the final version of the lamp.
You could you use the Arduino board, but it would be inconvenient not just from the point of view of cost, but also from the point of view of size and consumption … In reality, what we need is just the microcontroller with bootloader and a few external components.
If our Atmega has no bootloader, we need to load it, but first things first … Let us assume that when we already have the bootloader onboard.
To be able to upload the sketch we have to use the connections as shown in the figure:

It important to remove the microcontroller from the board with which we are going to program, otherwise we will program that instead of our Atmega standalone.
As you can see the connections are very simple, you just connect power, TX and RX pins and RESET pin.
At this point from our Arduino IDE we can go to upload the sketch, of course, after selecting “Arduino Duemilanove or Nano w / ATmega328” from the Tools -> Board. And that’s it.
Of course, the same would apply if the Atmega is programmed to work with the 8Mhz internal oscillator. With the difference that we didn’t need the two capacitors and the crystal shown in the figure. To use the internal oscillator, however, we should re-program the bootloader (as we shall see in the next post).
If we have available (and I recommend you to buy it because it is a cheap and really usuful accessory) a USB / Serial converter like the Sparkfun FTDI Basic or Ardino USB-Serial Light, connections would as the following:

It’s nothing complicated, just the connections are almost as before: VCC, GND, RX, TX, while the reset is a bit different because it requires a 100nF capacitor between the pin DTR (or RTS – not to be confused with RST) and Atmega RST.
We have seen how to program a standalone ATmega328 with bootloader preinstalled, in the next post we will see how to load the bootloader on a virgin Atmega328 in both versions: with external 16mhz crystal, and with internal 8Mhz oscillator.

Arduino and ATmega328: A bit of clarity

Until a few weeks ago,  I didn’t know exactly what was the difference between Arduino and its “core” Atmega328.
I read here and there that the Atmega328 can work in stand-alone, with or without the Arduino bootloader, and even in its minimal configuration, without any external components.
I was so confused about what exactely is Arduino and the ATmega328 “without Arduino”, as they have not much information on the Internet.
Eventually, with a lot of patience, “munching” here and some information on various blogs, reading magazines and books, and doing field trials, I finally came on the bulb (or LED) in my head and all appeared more clearly.
So I decided to publish this post where I explain briefly and simpy (and probably not in a totally professional way – I would ask apologize if there are any inaccuracies) what is Arduino and what sets it apart from the Atmega328 (which is included in last generation Arduino boards).
If I had to define the Arduino project, i can say that Arduino is an open source hardware & software platform which allows you to use more quickly and easily the potential offered by the microcontroller ATmega328.
The hardware part, is typically represented by the boards listed on the official website, with lots of open schemes that allow us to realize by ourself the various Arduino boards or modify and customize them to our liking. The software part is instead represented by the often quoted bootloader, libraries and by the IDE interface that allows you to program and debug our Arduino board.
But what are the differences between Arduino and its ATmega328 microcontroller and what are the advantages in microcontroller programming?
From the perspective of hardware, the Arduino board (for example Arduino UNO) is ready for use: it has everything we need to program the microcontroller just plugging the board into the USB port of the PC: it has on board an internal power connector, a USB port, a processor that acts as a USB / Serial converter, a power LED, a status LED connected to pin 13, two LEDs indicating TX / RX, female strip header for connection of  I / O ports and of course our ATmega328 microcontroller with Arduino bootloader already loaded.
In this way, opening the IDE and selecting the serial port of the PC we can load our sketch with a button and in a few seconds (typically 2-3). The upload is done via the serial port emulated by USB, which is connected to the TX and RX pin of the Atmega (pins respectively 3 and 2).
From the point of view of the software, the bootloader preloaded on Atmega (whether that is mounted on an Arduino board or just on a breadboard), is what allows serial communication with our PC. Without the bootloader to load the sketch (our “programs”), we would need an AVR programmer, more expensive, a bit ‘more cumbersome to use and slower to load the sketch. The bootloader is therefore a program, a firmware might say, whose job is basically to upload our sketch compiled into the flash memory of the microcontroller via serial communication, making sure that this program is not going to overwrite the memory area where bootloader resides. So when we upload a sketch we’re going to write in a zone of free memory and the bootloader is not affected and remain intact.
The main advantage compared to Atmega without bootloader, as we have seen, is that it can be uploaded via a simple serial communication, and at a faster rate than that which we directly loading the sketch using AVR programmer.
In addition to the bootloader, we have included libraries in the Arduino IDE. These libraries add many functions and constants that make it possible to greatly simplify the code we are going to write making it much more usable than the standard microcontroller. All this is managed through the IDE, which is the Arduino interface in which we write the sketchs, we upload and debug.

That said (hoping not to have bored and to be able explain without creating further confusion) in the next post we will see how to build a stand-alone Arduino, and how to program the ATmega328 without a bootloader, solution that sometimes could be advantageous.