I bought an Arduino Due a while back, and not having anything seriously pressing, it was set aside for other things.

The Due has a lot of differences from other Arduinos for various reasons.  The stuff you'll see on most websites leads with "it's 32 bits and runs at 3.3 volts!".  And those are important - any non-EE like me using an Arduino thinks at 5 volts, and in some cases you can blow up a Due with that much voltage.  But there are more important differences:

  • 4 serial connections
    The Mega has 4 also, but the Uno and Leonardo have 1.  Some things, like GPS receivers and the APRS Shield use serial connections, so this is a more-is-merrier situation.
  • 2 I2C channels broken out and labeled
    All of the Arduinos have I2C interfaces, but they are not labeled on the Uno, Leonardo, and Mega.  Really, this is just an inconvenience because you can look up the correct pins.  The Due labels them so you don't have to look them up, and the Due is the only current Arduino board that has two I2C interfaces.
    I2C is useful for a lot of sensors, including temperature sensors, EEPROMs, real-time clocks, digital compass modules, and DACs.
  • 2 Digital-Analog Converters (DACs)
    On the Uno, Leonardo, and Mega, there are no DAC converters - the analogWrite command writes to PWM outputs on those processors and that output is still 5V, but the output is a square wave that makes some things (like LEDs) look like you've reduced the voltage, when really you've reduced the amount of time that the voltage is on.  Wikipedia has a longer explanation.
    DAC converters do not output a PWM signal.  Instead the actual voltage is output, so if you give a 3.3V DAC a command corresponding to 50%, it will output 1.65V DC (NOT PWM!).
  • Controller Area Network (CAN) breakouts
    CAN is mostly used in vehicles in part of the On Board Diagnostics (OBD-II) system, but it is being adopted elsewhere.  It's adoption may continue with increased adoption of the Internet of Things.
  • Digital Signal Processing
    Perhaps one of the more interesting parts of the board where amateur radio is concerned is that the main chip (where all the magic happens) is powerful enough (between being 32 bits and 84 MHz) that it can do Fast Fourier Transform operations as well as number crunching operations.  Since there are both ADCs and DACs, an analog input can be sampled to digital data, processed, and then output through the DAC back to an analog waveform.  See an example at M0XPD's blog.  This also enables the use of the Due as an SDR (another link to M0XPD's blog).

I'm going to be doing a lot more here with the Due, so this should break me out of the no-post-slump I've been in.

-73-


Category: Arduino
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About the Author

Andrew is the owner of this blog and enjoys computer programming, building things, and photography. He's a pretty busy guy, which explains why updates to this blog are so infrequent.

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