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    Axon Microcontroller


    Technical details for those technically inclined.

    SoR Datasheets Axon Datasheets App for Android
    Offline version of Axon series datasheets - for those emergency situations when you don't have internet access.
    (download at Android Market)


      Axon Microcontroller

      Total weight is 34 grams.
      Four 4-40 screw holes make mounting onto your robot easy.



      The Axon is designed to be fully functional from a single battery source, although you can easily plug in additional parallel batteries to the power bus.

      Absolute minimum required voltage is 5.35V, while the recommended battery voltage is 6V to 7.2V. Absolute maximum voltage at 10V, however most servos cannot handle above 6V to 7.2V before being damaged.

      There are two power buses. ADC pins 0 to 15 are regulated at 5V, while all other pins are directly connected to your battery. There is also a 3.3V output pin (see current tolerances).

      The Axon has polarity protection features, meaning that it is designed to protect itself if you accidentally plug your battery in reverse. However, it will NOT protect any external component connected to the unregulated battery bus.

      This is how the pins are set up in terms of power and signal. Refer to your Axon board for pin numbers.

      Axon Power Bus Locations

      Pins	Voltage
      E2-E7	battery
      H2-H6	battery
      Bat	battery (input)
      A0-A7	battery
      J6	battery
      C0-C7	battery
      0-15	5V regulated
      3.3V	3.3V (output)
      G	ground
      +	battery
      -	ground

    Axon Pinout


      In addition to normal digital I/O functionality, some pins come with additional special features.

      Hardware PWM
      Hardware PWM is perfect for creating a perfect high frequency squarewave without any cost to the processor. Servos using hardware PWM can only be used on 16 bit pins, while regular DC motors can be used on any PWM pin.
      8-bit timer pins: H6 (T2)
      16-bit timer pins: E3/E4/E5 (T3), H3/H4/H5 (T4)

      The UART is great for sending and receiving serial data, such as from a GPS, a camera, external memory, other microcontrollers, etc.
      pins: U0, U2, U3, U1 is connected to USB

      The ADC, or analog to digital converter, is great for reading in analog sensor data (Sharp IR, photoresistor, accelerometers, gyros, etc).
      pins: 0-15 (F0-F7, K0-K7)

      External Interrupts
      External interrupts are useful for triggering interrupt code when important external events occur. Use these for encoders, sonar, and other time important sensors.
      pins: E4-E7 and D0-D3 (I2C, UART 1 pins)


      All ADC power bus pins get power from the 5V LDO voltage regulator with maximum allowable current of 1.5A. Adding a heat sink to the regulator can raise this amount depending on various environmental factors. See the FAQ for more on heat sinks.

      The Axon has been tested to handle at least 5A on each power bus, but can in theory handle ~13A. Placing your high current draw components near the battery can up this number. This limitation is entirely based on power bus tracing thickness, meaning that if you require higher currents you must make your own separate power bus.

      Individual I/O pins can supply about ~20mA power, each. Exceeding this number could damage the I/O pin.

      The Axon also has a special regulated 3.3V output connector if you have any components or sensors that require this voltage. This pin cannot supply more than about 73mA, or 90mA if you aren't using USB. If you find that USB becomes unstable or fails to work when using this output, make sure you aren't overdrawing current and place a 4.7mF tantalum capacitor (polarized) between 3.3V and ground.

      If you exceed the specs of the 3.3V output, you can permanently damage the USB. Do not just plug anything into it without first verifying the current draw is ok and that no voltage transients will occur.

      You must also keep in mind the current tolerances of the included Hitec 572125S on/off switch. These are the limits they quoted it at:
      "A conservative estimate would be in the 10 amp range for the 572125S and 16 amp range for the 54407S. But again these are just estimates."
      - Hitec Sales Manager


      All electronics creates electronic noise and sudden voltage spikes/drops that can potential cause problems. The Axon has been intentionally designed to minimize this noise, and in fact during extensive tests I found no detectable (non-negligible) noise. However, your needs may be different. If you find you are using highly sensitive sensors, I recommended attaching additional noise suppression ceramic capacitors in parallel to the regulated power bus.


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