Planet Arduino

The hacking life is not without its challenges, and chief among these is the tendency to always be in acquisition mode. When we come across a great deal on bulk equipment, or see a chance to rescue some obscure gear from the e-waste stream, we generally pounce on it, regardless of the advisability.

We imagine this is why [Nathan] ended up with a hoard of PS/2 keyboards. Seriously, there are like thousands of the things. And rather than lug a computer to them for testing, [Nathan] put together this handy Arduino-based portable tester to see which keyboards still have some life left in them. The video below goes into detail on the build, but the basics are pretty simple — an Arduino, a 16×2 LCD display, and a few bits and bobs to run it off a LiPo pack and charge it up. Plus, of course, a PS/2 jack to plug in a keyboard and power it up. Interestingly, the 16×2 display is an old Parallax unit, from the days when RadioShack still existed and sold their stuff. That required a little effort to get it working with the Arduino, but in the end it works like a charm — plug in a keyboard and whatever you type shows up on the screen.

Of course, it’s hard to look at something like this, and that mountain of keyboards in the background, and not scheme up ways to really automate the whole test process. Perhaps an old 3D printer with a stylus mounted where the hot end would go could press each key in turn while the tester output is recorded — something like this Wordle-bot, but on a keyboard scale. That kind of goes against [Nathan]’s portability goal, but it’s still fun to think about.

Salvaging a beefy motor is one life’s greatest pleasures for a hacker, but, when it comes to using it in a new project, the lack of specs and documentation can be frustrating. [The Post Apocalyptic Inventor] has a seemingly endless stockpile of scavenged motors, and decided to do something about the problem.

Once again applying his talent for junk revival, [TPAI] has spent the last year collecting, reverse-engineering and repairing equipment built in the 1970s, to produce a complete electric motor test setup. Parameters such as stall torque, speed under no load, peak power, and more can all easily be found by use of the restored test equipment. Key operating graphs that would normally only be available in a datasheet can also be produced.

The test setup comprises of a number of magnetic particle brakes, combined power supply and control units, a trio of colossal three-phase dummy loads, and a gorgeously vintage power-factor meter.

Motors are coupled via a piece of rubber to a magnetic particle brake. The rubber contains six magnets spaced around its edge, which, combined with a hall sensor,  are used to calculate the motor’s rotational speed. When power is applied to the coil inside the brake, the now magnetised internal powder causes friction between the rotor and the stator, proportional to the current through the coil. In addition to this, the brake can also measure the torque that’s being applied to the motor shaft, which allows the control units to regulate the brake either by speed or torque. An Arduino slurps data from these control units, allowing characteristics to be easily graphed.

If you’re looking for more dynamometer action, last year we featured this neatly designed unit – made by some Cornell students with an impressive level of documentation.

Updated 27/02/2013

Introduction

After much waiting the Arduino Due has been released, so let’s check it out. We’ll run through the specifications and some areas of interest, see what’s different, some random notes – then try out some of the new features. Before moving forward note that it might look the same - the Due is not a drop-in replacement for older boards – even the Mega2560. It’s different.

First announced in late 2011, the Due is the Arduino team’s first board with a 32-bit processor – the Atmel SAM3X8E ARM Cortex-M3 CPU. With an 84 Mhz CPU speed and a host of interfaces and I/O, this promises to be the fastest and most functional Arduino board ever. According to the official Arduino press release:

Arduino Due is ideal for those who want to build projects that require high computing power such as the remotely-controlled drones that, in order to fly, need to process a lot of sensor data per second.
Arduino Due gives students the opportunity to learn the inner workings of the ARM processor in a cheaper and much simpler way than before.
To Scientific projects, which need to acquire data quickly and accurately, Arduino Due provides a platform to create open source tools that are much more advanced than those available now.
The new platform enables the open source digital fabrication community (3d Printers, Laser cutters, CNC milling machines) to achieve higher resolutions and faster speed with fewer components than in the past.

Sounds good – and the Due has been a long time coming, so let’s hope it is worth the wait. The SAM3X CPU holds a lot of promise for more complex projects that weren’t possible with previous ATmega CPUs, so this can be only a good thing.

Specifications

First of all, here’s the Due in detail – top and bottom (click to enlarge):

You can use Mega-sized protoshields without any problem (however older shields may miss out on the upper I2C pins) – they’ll physically fit in … however their contents will be a different story:

The specifications of the Due are as follows (from Arduino website):

Right away a few things should stand out – the first being the operating voltage – 3.3V. That means all your I/O needs to work with 3.3V – not 5V. Don’t feed 5V logic line into a digital input pin and hope it will work – you’ll damage the board. Instead, get yourself some logic level converters. However there is an IOREF pin like other Arduino boards which intelligent shields can read to determine the board voltage. The total output current for all I/O lines is also 130 mA … so no more sourcing 20mA from a digital ouput for those bright LEDs.

The power regulator for 5V has been changed from linear to switching – so no more directly inserting 5V into the 5V pin. However the 3.3V is through an LDO from 5v.

Each digital I/O pin can source 3 or 15 mA – or sink 6 or 9 mA … depending on the pin. High-current pins are CAN-TX, digital 1, 3~12, 23~51, and SDA1. The rest are low current. And there’s still an LED on digital 13. You will need to redesign any existing projects or shields if moving to the Due.

The analogue inputs now have a greater resolution – 12-bits. That means it can return a value of  0~4095 representing 0~3.3V DC. To activate this higher resolution you need to use the function analogReadResolution(12).

Memory – there isn’t any EEPROM in the SAM3X – so you’ll need external EEPROMs to take care of more permanent storage. However there’s 512 KB of flash memory for sketches – which is huge. You have to see it to believe it:

Excellent. A new feature is the onboard erase button. Press it for three seconds and it wipes out the sketch. The traditional serial line is still digital 0/1 – which connect to the USB controller chip.

Hardware serial – there’s four serial lines. Pulse-width modulation (PWM) is still 8-bit and on digital pins 2~13.

The SPI bus is on the ICSP header pins to the right of the microcontroller – so existing shields that use SPI will need to be modified – or experiment with a LeoShield:

You can also use the extended SPI function of the SAM3X which allow the use of digital pins 4, 10 or 52 for CS (chip select).

The SAM3X supports the automtive CAN bus, and the pins have been brought out onto the stacked header connectors – however this isn’t supported yet in the IDE.

There are two I2C buses – located on digital 20/21 and the second is next to AREF just like on the Leonardo.

There’s a 10-pin JTAG mini-header on the Due, debug pins and a second ICSP for the ATmega16U2 which takes care of USB. Speaking of USB – there’s two microUSB sockets. One is for regular programming via the Arduino IDE and the USB interface, the other is a direct native USB programming port direct to the SAM3X.

The SAM3X natively supports Ethernet, but this hasn’t been implemented on the hardware side for the Due. However some people in the Arduino forum might have a way around that.

Using the Due

First of all – at the time of writing – you need to install Arduino IDE v1.5.1 release 2 – a beta version. Windows users – don’t forget the USB drivers. As always, backup your existing installation and sketch files somewhere safe – and you can run more than one IDE on the same machine.

When it comes time to upload your sketches, plug the USB cable into the lower socket on the Due – and select Arduino Due (Programming Port) from the Tools>Board menu in the IDE.

Let’s upload a sketch now (download) – written by Steve Curd from the Arduino forum. It calculates Newton Approximation for pi using an infinite series. As you can see from the results below, the Due is much faster (690 ms) than the Mega2560 (5765 ms). Click the image to enlarge:

Next, let’s give the digital-to-analogue converters a test. Finally we have two, real, 12-bit DACs with the output pins being … DAC0 and DAC1. No more mucking about with external R-C filters to get some audio happening. These pins provides true analogue outputs which is controlled by the analogWrite() function. To use them is very simple – consider the following example sketch which creates a triangle wave:

void setup() 
{
 analogWriteResolution(12); // 12-bit!
}

void loop() 
{
 for(int x=0; x<4096; x++) 
 {
 analogWrite(DAC0, x); // use DAC1 for ... DAC1
 }
 for(int x=4095; x>=0; --x) 
 {
 analogWrite(DAC0, x);
 }
}

And the results from the DSO (click image to enlarge):

This opens up all sorts of audio possibilities. With appropriate wavetable data saved in memory you could create various effects. However the DAC doesn’t give a full 0~3.3V output – instead it’s 1/6 to 5/6 of the Aref voltage. With the IDE there are example sketches that can play a .wav file from an SDcard – however I’d still be more inclined to use an external shield for that. Nevertheless for more information, have a look at the Audio library. Furthermore, take heed of the user experiences noted in the Arduino forum – it’s very easy to destroy your DAC outputs. In the future we look forward to experimenting further with the Due – so stay tuned.

Getting a Due

Good luck … at the time of writing – the Dues seem to be very thin on the ground. This may partly be due to the limited availability of the Atmel SAM3X8E. My contacts in various suppliers say volumes are quite limited.

Quality

I really hope this is a rare event, however one of the Dues received had the following fault in manufacturing:

One side of the crystal capacitor wasn’t in contact with the PCB. However this was a simple fix. How the QC people missed this … I don’t know. However I’ve seen a few Arduinos of various types, and this error is not indicative of the general quality of Arduino products.

Where to from here?

Visit the official Arduino Due page, the Due discussion section of the Arduino forum, and check out the reference guide for changes to functions that are affected by the different hardware.

Conclusion

Well that’s my first take on the Due – powerful and different. You will need to redesign existing projects, or build new projects around it. And a lot of stuff on the software side is still in beta. So review the Due forum before making any decisions. With that in mind – from a hardware perspective – it’s a great step-up from the Mega2560.

So if you’re interested – get one and take it for a spin, it won’t disappoint. The software will mature over time which will make life easier as well. If you have any questions (apart from Arduino vs. Raspberry Pi) leave a comment and we’ll look into it.

Updated 27/02/2013

Introduction

After much waiting the Arduino Due has been released, so let’s check it out. We’ll run through the specifications and some areas of interest, see what’s different, some random notes – then try out some of the new features. Before moving forward note that it might look the same - the Due is not a drop-in replacement for older boards – even the Mega2560. It’s different.

First announced in late 2011, the Due is the Arduino team’s first board with a 32-bit processor – the Atmel SAM3X8E ARM Cortex-M3 CPU. With an 84 Mhz CPU speed and a host of interfaces and I/O, this promises to be the fastest and most functional Arduino board ever. According to the official Arduino press release:

Arduino Due is ideal for those who want to build projects that require high computing power such as the remotely-controlled drones that, in order to fly, need to process a lot of sensor data per second.
Arduino Due gives students the opportunity to learn the inner workings of the ARM processor in a cheaper and much simpler way than before.
To Scientific projects, which need to acquire data quickly and accurately, Arduino Due provides a platform to create open source tools that are much more advanced than those available now.
The new platform enables the open source digital fabrication community (3d Printers, Laser cutters, CNC milling machines) to achieve higher resolutions and faster speed with fewer components than in the past.

Sounds good – and the Due has been a long time coming, so let’s hope it is worth the wait. The SAM3X CPU holds a lot of promise for more complex projects that weren’t possible with previous ATmega CPUs, so this can be only a good thing.

Specifications

First of all, here’s the Due in detail – top and bottom (click to enlarge):

You can use Mega-sized protoshields without any problem (however older shields may miss out on the upper I2C pins) – they’ll physically fit in … however their contents will be a different story:

The specifications of the Due are as follows (from Arduino website):

Right away a few things should stand out – the first being the operating voltage – 3.3V. That means all your I/O needs to work with 3.3V – not 5V. Don’t feed 5V logic line into a digital input pin and hope it will work – you’ll damage the board. Instead, get yourself some logic level converters. However there is an IOREF pin like other Arduino boards which intelligent shields can read to determine the board voltage. The total output current for all I/O lines is also 130 mA … so no more sourcing 20mA from a digital ouput for those bright LEDs.

The power regulator for 5V has been changed from linear to switching – so no more directly inserting 5V into the 5V pin. However the 3.3V is through an LDO from 5v.

Each digital I/O pin can source 3 or 15 mA – or sink 6 or 9 mA … depending on the pin. High-current pins are CAN-TX, digital 1, 3~12, 23~51, and SDA1. The rest are low current. And there’s still an LED on digital 13. You will need to redesign any existing projects or shields if moving to the Due.

The analogue inputs now have a greater resolution – 12-bits. That means it can return a value of  0~4095 representing 0~3.3V DC. To activate this higher resolution you need to use the function analogReadResolution(12).

Memory – there isn’t any EEPROM in the SAM3X – so you’ll need external EEPROMs to take care of more permanent storage. However there’s 512 KB of flash memory for sketches – which is huge. You have to see it to believe it:

Excellent. A new feature is the onboard erase button. Press it for three seconds and it wipes out the sketch. The traditional serial line is still digital 0/1 – which connect to the USB controller chip.

Hardware serial – there’s four serial lines. Pulse-width modulation (PWM) is still 8-bit and on digital pins 2~13.

The SPI bus is on the ICSP header pins to the right of the microcontroller – so existing shields that use SPI will need to be modified – or experiment with a LeoShield:

You can also use the extended SPI function of the SAM3X which allow the use of digital pins 4, 10 or 52 for CS (chip select).

The SAM3X supports the automtive CAN bus, and the pins have been brought out onto the stacked header connectors – however this isn’t supported yet in the IDE.

There are two I2C buses – located on digital 20/21 and the second is next to AREF just like on the Leonardo.

There’s a 10-pin JTAG mini-header on the Due, debug pins and a second ICSP for the ATmega16U2 which takes care of USB. Speaking of USB – there’s two microUSB sockets. One is for regular programming via the Arduino IDE and the USB interface, the other is a direct native USB programming port direct to the SAM3X.

The SAM3X natively supports Ethernet, but this hasn’t been implemented on the hardware side for the Due. However some people in the Arduino forum might have a way around that.

Using the Due

First of all – at the time of writing – you need to install Arduino IDE v1.5.1 release 2 – a beta version. Windows users – don’t forget the USB drivers. As always, backup your existing installation and sketch files somewhere safe – and you can run more than one IDE on the same machine.

When it comes time to upload your sketches, plug the USB cable into the lower socket on the Due – and select Arduino Due (Programming Port) from the Tools>Board menu in the IDE.

Let’s upload a sketch now (download) – written by Steve Curd from the Arduino forum. It calculates Newton Approximation for pi using an infinite series. As you can see from the results below, the Due is much faster (690 ms) than the Mega2560 (5765 ms):

Next, let’s give the digital-to-analogue converters a test. Finally we have two, real, 12-bit DACs with the output pins being … DAC0 and DAC1. No more mucking about with external R-C filters to get some audio happening. These pins provides true analogue outputs which is controlled by the analogWrite() function. To use them is very simple – consider the following example sketch which creates a triangle wave:

void setup() 
{
 analogWriteResolution(12); // 12-bit!
}
void loop() 
{
 for(int x=0; x<4096; x++) 
 {
 analogWrite(DAC0, x); // use DAC1 for ... DAC1
 }
 for(int x=4095; x>=0; --x) 
 {
 analogWrite(DAC0, x);
 }
}

And the results from the DSO:

 

Getting a Due

Good luck … at the time of writing – the Dues seem to be very thin on the ground. This may partly be due to the limited availability of the Atmel SAM3X8E. My contacts in various suppliers say volumes are quite limited.

Quality

I really hope this is a rare event, however one of the Dues received had the following fault in manufacturing:

One side of the crystal capacitor wasn’t in contact with the PCB. However this was a simple fix. How the QC people missed this … I don’t know. However I’ve seen a few Arduinos of various types, and this error is not indicative of the general quality of Arduino products.

Where to from here?

Visit the official Arduino Due page, the Due discussion section of the Arduino forum, and check out the reference guide for changes to functions that are affected by the different hardware.

Conclusion

Well that’s my first take on the Due – powerful and different. You will need to redesign existing projects, or build new projects around it. And a lot of stuff on the software side is still in beta. So review the Due forum before making any decisions. With that in mind – from a hardware perspective – it’s a great step-up from the Mega2560.

So if you’re interested – get one and take it for a spin, it won’t disappoint. The software will mature over time which will make life easier as well. If you have any questions (apart from Arduino vs. Raspberry Pi) leave a comment and we’ll look into it.

The post First look: Arduino Due appeared first on tronixstuff.

Introduction

Some of you may be using an Arduino Leonardo board, taking advantage of the newer ATmega32U4 microcontroller for various reasons. And rightly so – there’s the extra analogue I/O, virtual USB and the microUSB socket so you can use your phone charger cable. However with the new microcontroller comes a few changes to the board pinouts – I2C and SPI have moved. So if you have a nice Ethernet shield or something using I2C – you’re basically out of luck… until now. The problem has been solved nicely by the team at GorillaBuilderz have created their LeoShield:

Use

You simply place it on the Leonardo, and then the older legacy shield on top. The LeoShield redirects the I2C pins back to A4 and A5, and also sends the SPI lines back to D11~D13. For example, our Ethernet shield:

The ICSP pins are also extended from the Leonardo to the LeoShield, for example:

however when inserting the LeoShield into your Leonardo, take care lining up all the pins before pushing the shield down. There is also the large prototyping area which has 5V , 3.3V and GND rails across the full width for convenience. The sticker on the rear of the shield is to insulate against any large items that may come in contact from the host board, however you can peel it off to realise the complete prototyping space.

Conclusion

It’s simple and it works – so if you need to use an older Arduino shield with a Leonardo the choice is simple – get yourself a Leoshield.

Disclaimer - The Leoshield was a review product received from GorillaBuilderz.

Thanks for reading tronixstuff.com. I’ve got some new tutorials coming up very soon, and a lot of existing posts are curently being updated – so follow things on twitter, Google+, subscribe  for email updates or RSS using the links on the right-hand column. And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other –  and we can all learn

The post Review: GorillaBuilderz LeoShield appeared first on tronixstuff.

Introduction

Some of you may be using an Arduino Leonardo board, taking advantage of the newer ATmega32U4 microcontroller for various reasons. And rightly so – there’s the extra analogue I/O, virtual USB and the microUSB socket so you can use your phone charger cable. However with the new microcontroller comes a few changes to the board pinouts – I2C and SPI have moved. So if you have a nice Ethernet shield or something using I2C – you’re basically out of luck… until now. The problem has been solved nicely by the team at GorillaBuilderz have created their LeoShield:

Use

You simply place it on the Leonardo, and then the older legacy shield on top. The LeoShield redirects the I2C pins back to A4 and A5, and also sends the SPI lines back to D11~D13. For example, our Ethernet shield:

The ICSP pins are also extended from the Leonardo to the LeoShield, for example:

however when inserting the LeoShield into your Leonardo, take care lining up all the pins before pushing the shield down. There is also the large prototyping area which has 5V , 3.3V and GND rails across the full width for convenience. The sticker on the rear of the shield is to insulate against any large items that may come in contact from the host board, however you can peel it off to realise the complete prototyping space.

Conclusion

It’s simple and it works – so if you need to use an older Arduino shield with a Leonardo the choice is simple – get yourself a Leoshield.

Disclaimer - The Leoshield was a review product received from GorillaBuilderz.

Thanks for reading tronixstuff.com. I’ve got some new tutorials coming up very soon, and a lot of existing posts are curently being updated – so follow things on twitter, Google+, subscribe  for email updates or RSS using the links on the right-hand column. And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other –  and we can all learn

Introduction

Over the last year or so Texas Instruments have been literally pushing their MSP430 development platform hard by offering an inexpensive development kit – their LaunchPad. For around ten dollars (not everyone could get it for $4.30) it includes a development board with flash emulation tool and USB interface, two of their microcontrollers, crystal, USB cable and some headers. It was (is?) a bargain and tens of thousands of LaunchPads were sold. Happy days.

However after the courier arrived and the parcel was opened, getting started with the LaunchPad was an issue for some people. Not everyone has been exposed to complex IDEs or university-level subjects on this topic. And to get started you needed to use a version of Code Composer Studio or IAR Embedded Workbench IDEs, which scared a few people off. So those LaunchPads went in the cupboard and gathered dust.

Well now it’s time to pull them out, as there’s a new way to program the MSP430 using a fork of the Arduino IDE – Energia. Put simply, it’s the Arduino IDE modified to compile and upload code to the LaunchPad, which makes this platform suddenly much more approachable.

Getting Started

You’ll need to download and install the appropriate USB drivers, then the IDE itself from here. To install the IDE you just download and extract it to your preferred location, in the same manner as the Arduino IDE. Then plug your LaunchPad into the USB. Finally,  load the IDE. Everything is familiar to the Arduino user, except the only surprise is the colour (red as a nod to TI perhaps…):

Looking good so far. All the menu options are familiar, the files have the .ino extension, and the preferences dialogue box is how we expect it. Don’t forget to select the correct port using the Tools > Serial port… menu. You will also need to select the type of MSP430 in your LaunchPad. At the time of writing there is support for three types listed below (and the first two are included with the LaunchPad v1.5):

• MSP430G2553 - <=16 MHz, 16KB flash, 512b SRAM, 24 GPIO, two 16-bit timers, UART, SPI, I2C, 8 ADC channels at 10-bit, etc. Cost around Au$3.80 each**
• MSP430G2452 - <=16 MHz, 8KB flash, 256b SRAM, 16 GPIO, one 16-bit timer, UART, I2C, 8 ADC channels, etc. Cost around Au$2.48 each**
• MSP430G2231 - <=16 MHz, 2KB flash, 128b SRAM, 10 GPIO, one 16-bit timer, SPI, I2C, 8 ADC channels, etc. Cost around Au$3.36 each**

** One-off ex-GST pricing from element14 Australia. In some markets it would be cheaper to buy another LaunchPad. TI must really be keen to get these in use.

There are some hardware<>sketch differences you need to be aware of. For example, how to refer to the I/O pins in Energia? A map has been provided for each MSP430 at the Energia wiki, for example the G2553:

As you can imagine, MSP430s are different to an AVR, so a lot of hardware-specific code doesn’t port over from the world of Arduino. One of the first things to remember is that MSP430s are 3.3V devices. Code may or may not be interchangeable, so a little research will be needed to match up the I/O pins and rewrite the sketch accordingly. You can refer to pins using the hardware designator on the LaunchPad (e.g. P1_6) or the physical pin number. For example – consider the following sketch:

void setup() 
{ 
 // initialize the digital pins as an output.
 pinMode(P1_0, OUTPUT); // LED 1
 pinMode(P1_6, OUTPUT); // LED 2
}
void loop() {
 digitalWrite(P1_6, HIGH); 
 digitalWrite(P1_0, HIGH); 
 delay(100); 
 digitalWrite(P1_6, LOW); 
 digitalWrite(P1_0, LOW); 
 delay(100); 
}

You could have used 2 (for physical pin 2) instead of P1_0 and 14 (physical pin … 14!) instead of P1_6. It’s up to you. Another quick example is this one – when the button is pressed, the LEDs blink a few times:

const int redLED = P1_0;
const int greenLED = P1_6;
const int button = P1_3; // button S2 (on the left)
int a = 0;

void setup()
{
 pinMode(redLED, OUTPUT);
 pinMode(greenLED, OUTPUT); 
 pinMode(button, INPUT_PULLUP); // note _PULLUP
 digitalWrite(redLED, LOW);
 digitalWrite(greenLED, LOW); 
}
void loop()
{
 if (digitalRead(button)==LOW)
 {
 for (a=0; a<10; a++)
 {
 digitalWrite(redLED, HIGH);
 digitalWrite(greenLED, LOW); 
 delay(200);
 digitalWrite(redLED, LOW);
 digitalWrite(greenLED, HIGH); 
 delay(200);
 }
 digitalWrite(redLED, LOW);
 digitalWrite(greenLED, LOW); 
 }
}

Due to the wiring of the LaunchPad, when you press the button, P1_3 is pulled LOW. For the non-believers, here it is in action:

So where to from here? There are many examples in the Energia IDE example menu, including some examples for the Energia libraries. At the time of writing there is: Servo, LiquidCrystal, IRremote, SPI, wire, MSPflash and Stepper. And as the Energia project moves forward more may become available. For help and discussion, head over to the 4-3-Oh forum and of course the Energia website. And of course there’s the TI MSP430 website.

Conclusion

Well that was interesting to say the least. If you have a project which needs to be low-cost, fits within the specifications of the MSP430, has a library, you’re not hung up on brand preference, and you just want to get it done – this is a viable option. Hopefully after time some of you will want to work at a deeper level, and explore the full IDEs and MSP430 hardware available from TI. But for the price, don’t take my word for it – try it yourself. 

In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitter, Google+, subscribe  for email updates or RSS using the links on the right-hand column? And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other –  and we can all learn something.

The post Exploring the TI MSP430 platform with Energia Arduino-compatible IDE appeared first on tronixstuff.

Introduction

Over the last year or so Texas Instruments have been literally pushing their MSP430 development platform hard by offering an inexpensive development kit – their LaunchPad. For around ten dollars (not everyone could get it for $4.30) it includes a development board with flash emulation tool and USB interface, two of their microcontrollers, crystal, USB cable and some headers. It was (is?) a bargain and tens of thousands of LaunchPads were sold. Happy days.

However after the courier arrived and the parcel was opened, getting started with the LaunchPad was an issue for some people. Not everyone has been exposed to complex IDEs or university-level subjects on this topic. And to get started you needed to use a version of Code Composer Studio or IAR Embedded Workbench IDEs, which scared a few people off. So those LaunchPads went in the cupboard and gathered dust.

Well now it’s time to pull them out, as there’s a new way to program the MSP430 using a fork of the Arduino IDE – Energia. Put simply, it’s the Arduino IDE modified to compile and upload code to the LaunchPad, which makes this platform suddenly much more approachable.

Getting Started

You’ll need to download and install the appropriate USB drivers, then the IDE itself from here. To install the IDE you just download and extract it to your preferred location, in the same manner as the Arduino IDE. Then plug your LaunchPad into the USB. Finally,  load the IDE. Everything is familiar to the Arduino user, except the only surprise is the colour (red as a nod to TI perhaps…):

Looking good so far. All the menu options are familiar, the files have the .ino extension, and the preferences dialogue box is how we expect it. Don’t forget to select the correct port using the Tools > Serial port… menu. You will also need to select the type of MSP430 in your LaunchPad. At the time of writing there is support for three types listed below (and the first two are included with the LaunchPad v1.5):

• MSP430G2553 - <=16 MHz, 16KB flash, 512b SRAM, 24 GPIO, two 16-bit timers, UART, SPI, I2C, 8 ADC channels at 10-bit, etc. Cost around Au$3.80 each**
• MSP430G2452 - <=16 MHz, 8KB flash, 256b SRAM, 16 GPIO, one 16-bit timer, UART, I2C, 8 ADC channels, etc. Cost around Au$2.48 each**
• MSP430G2231 - <=16 MHz, 2KB flash, 128b SRAM, 10 GPIO, one 16-bit timer, SPI, I2C, 8 ADC channels, etc. Cost around Au$3.36 each**

** One-off ex-GST pricing from element14 Australia. In some markets it would be cheaper to buy another LaunchPad. TI must really be keen to get these in use.

There are some hardware<>sketch differences you need to be aware of. For example, how to refer to the I/O pins in Energia? A map has been provided for each MSP430 at the Energia wiki, for example the G2553:

As you can imagine, MSP430s are different to an AVR, so a lot of hardware-specific code doesn’t port over from the world of Arduino. One of the first things to remember is that MSP430s are 3.3V devices. Code may or may not be interchangeable, so a little research will be needed to match up the I/O pins and rewrite the sketch accordingly. You can refer to pins using the hardware designator on the LaunchPad (e.g. P1_6) or the physical pin number. For example – consider the following sketch:

void setup() { 
 // initialize the digital pins as an output.
 pinMode(P1_0, OUTPUT); // LED 1
 pinMode(P1_6, OUTPUT); // LED 2
}

void loop() {
 digitalWrite(P1_6, HIGH); 
 digitalWrite(P1_0, HIGH); 
 delay(100); 
 digitalWrite(P1_6, LOW); 
 digitalWrite(P1_0, LOW); 
 delay(100); 
}

You could have used 2 (for physical pin 2) instead of P1_0 and 14 (physical pin … 14!) instead of P1_6. It’s up to you. Another quick example is this one – when the button is pressed, the LEDs blink a few times:

const int redLED = P1_0;
const int greenLED = P1_6;
const int button = P1_3; // button S2 (on the left)

int a = 0;
void setup()
{
 pinMode(redLED, OUTPUT);
 pinMode(greenLED, OUTPUT); 
 pinMode(button, INPUT_PULLUP); // note _PULLUP
 digitalWrite(redLED, LOW);
 digitalWrite(greenLED, LOW); 
}

void loop()
{
 if (digitalRead(button)==LOW)
 {
 for (a=0; a<10; a++)
 {
 digitalWrite(redLED, HIGH);
 digitalWrite(greenLED, LOW); 
 delay(200);
 digitalWrite(redLED, LOW);
 digitalWrite(greenLED, HIGH); 
 delay(200);
 }
 digitalWrite(redLED, LOW);
 digitalWrite(greenLED, LOW); 
 }
}

Due to the wiring of the LaunchPad, when you press the button, P1_3 is pulled LOW. For the non-believers, here it is in action:

So where to from here? There are many examples in the Energia IDE example menu, including some examples for the Energia libraries. At the time of writing there is: Servo, LiquidCrystal, IRremote, SPI, wire, MSPflash and Stepper. And as the Energia project moves forward more may become available. For help and discussion, head over to the 4-3-Oh forum and of course the Energia website. And of course there’s the TI MSP430 website.

Conclusion

Well that was interesting to say the least. If you have a project which needs to be low-cost, fits within the specifications of the MSP430, has a library, you’re not hung up on brand preference, and you just want to get it done – this is a viable option. Hopefully after time some of you will want to work at a deeper level, and explore the full IDEs and MSP430 hardware available from TI. But for the price, don’t take my word for it – try it yourself. 

In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitter, Google+, subscribe  for email updates or RSS using the links on the right-hand column? And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other –  and we can all learn something.