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Bareduino328: Building your Barebones Microcontroller

Description:
Need lots of Arduino Compatible controllers, but don’t need the price tag of a full development platform? This handy little kit is perfect for anyone who is experienced with the Arduino Compatible Micro-controllers, and needs to include a lot more of them in his/her next project. If you follow the steps on this page making a project on a breadboard is a snap, tie as many ATMEGA328’s together as you need to. The sky is the limit, and you don’t have to buy in bulk to get a great deal!

Package Contents:
• 1 x P-DIP ATMEGA328P-PU programmed with Duemilanove Bootloader
• 3 x Through-Hole 22pF Capacitors (2 for crystal and 1 for Analog power smoothing)
• 1 x Through-Hole HC-49S 16 MHz Crystal (for clock)
• 1 x Through-Hole 1/4 Watt 22 K ohm resistor (for reset pullup)
Note: Breadboard and wires are not included in the Bareduino and Bareduino Plus kits.

Optional but handy:

  • 1 x Through-Hole 1/4 Watt 1 K ohm resistor (for an LED)
  • 1 x Through-Hole 5mm LED (for Blink)

Key Features:
• Lower the cost and size of your next project
• Ideal for minimalistic deployments
• easily tie multiple controllers together to perform more complex tasks than possible with a single Micro-controller

The Setup

The process to making your first micro-controller come to life can be quite involved, even for someone with a little experience under there belt. To make the process less of a headache, we have provided this easy to follow guide. Follow the steps in this guide and your Bareduino will be up and running in no time!

This is a schematic of what you will be building

The following items are needed for construction of your Bareduino (programmer method and parts in separate section).

  • A Bareduino kit (Bareduino or Bareduino Plus)
  • Breadboard
  • Jumper wires
  • Grounding strap (chip is ESD sensitive)

 

 bareduino steps 1 and 2NOTE: This is a diagram of a 170-hole mini-breadboard. It is not drawn to scale.2.)Insert the ATmega328 microcontroller with Pin-1 at e-1.
 Step 1.) DetailsGet a breadboard, any old bread board will do the job as long as it is at least as big as this one. Power rails are nice, but since not everyone has them, this guide uses the most basic possible approach. (The breadboard pictured here comes with our Arduino Compatible Prototyping shield)
 Step 2.) DetailsTime to open up that fancy ESD bag and pull off the Atmega328 chip. Put pin one (where the inset dot is in the bottom left corner of the chip) snug against he bottom left of the board.Make sure that the chip strattles the empty area in between the holes. If you don’t do this your chip will definitely not work because the left and right side of the chip will be tied together, causing much sadness.
 bareduino steps 3 and 4

    1. Insert a red (positive) wire from a-9 to a-17.
      Insert a red wire from b-10 to b15.
      Insert a green (ground) wire from i-15 to i-17.
      Insert a green wire from j-7 to j-15.
    2. Insert the 1/4 W (or whatever wattage you want) 22K Ohm resistor from a-1 to a-7.
 Step 3.) DetailsPlace your power (Vdd) and ground wires as shown (green wires are ground, and red wires are power 5 Volts for most setups).
 Step 4.) DetailsPut the 22K pullup resistor between pin 1 and the Vdd (red wire). This keeps the device from resetting continuously.
 bareduino steps 5 and 6

    1. Insert the 16MHz crystal oscillator from c-15 to c-17.
    2. Insert a 22pF capacitor from e-15 to f-15.
      Insert a 22pF capacitor from e-17 to f-17.

 

  Step 5.) DetailsConnect the crystal pins to the rightmost two power bus lines.Step 6.) Details

Connect two of the three 22pF capacitors as shown in the image on the right. Each should connect to one of the crystal pins and the other connects to ground. This is what keeps the crystal running smooth.

 

 bareduino steps 7 and 8

    1. Insert a 22pF capacitor from i-7 to i-9.
      Insert a red wire from b-7 to g-9.
    2. Insert an LED from h-10 (positive side of LED) to h-16 (negative side of LED)
      Insert a 1/4 W (or any other wattage really) 1 K ohm resistor from g-15 to g-16
  Step 7.) If you plan on using the Analog ports you will want to regulate the supply to them with the third Capacitor as seen in the image below.

If you don’t put this in your analog ports will not be powered at all.

The 3rd 22pF Capacitor serves to help regulate the AVCC line and keeps your analog data clean. Later if you put a larger cap on your VCC you can technically get rid of that capacitor (as long as you are powering it using VCC).

Step 8.) Optional

It probably makes sense to add the LED and resistor for testing your Bareduino out now. Connecting as illustrated above should have you ready to load your first sketch as soon as you finish the next step.

 bareduino power it up

    1. Connect the red wire from d-7 to the positive terminal
      and a green wire from d-8 to the negative terminal of a 3.3 to 5V regulated supply.

WARNING: USING HIGHER VOLTAGES CAN DAMAGE YOUR ATMEGA328, AND IS LIKELY TO MAKE WHOEVER DOES IT SAD.

Congratulations, you have finished wiring a Bareduino 328.

Special thanks go out to K.W. Melvin for contributing those awesome diagrams used above, I really appreciate you sharing them with the community.

When referencing pins on the ATMEGA328 the following pin-out diagram can be invaluable, be sure to compare against it (keeping in mind that pin 1 in next to the circular notch in the corner).

These are really handy, don't forget to use them!

 Already built yours? Click here for the Programming guide You can look forward to a device testing, pin-out, and programming guide. Please let us know if there is anything else you need to know.

11 Responses to “Bareduino328: Building your Barebones Microcontroller”

  1. Do I use a 5v or a 3.3v FTDI cable.

    • The Bareduino kit’s crystal is balanced for 5V operation. So use the 5 Volt FTDI cable. Let me know if you need any more help, we should have an FTDI programming guide written this weekend.

  2. What pin (presumably 7) is connected to power (+). What pin (8? 22? both) is connected to ground? How can I tell if it is working? Does the crystal work both ways? Or only one way?

    • Peter,
      (I know I already answered this in your email, but I am sure other people have asked the same thing.)

      VCC (+) goes to 7 and 20, and Ground (-) goes to 8 and 22. If your set up is working an LED should blink when placed on pin 13.

      Respectfully,
      Joseph Dattilo

  3. I’m a little peeved right now. I bought the Bareduino Plus and your guide said to first build the Bareduino. I followed the guide, and cut off the leads to the capacitors so that they fit snugly to the breadboard. Then I switched over the the Bareduino Plus guide and it tells me to move the capacitors and now they won’t stretch to the holes. Bummer.

    • James,

      Great point! Where do you think I should add a note about the Bareduino Plus lead lengths? On the Bareduino Plus Page by the link, or above the wiring itself in the Bareduino guide?

      Respectfully,
      Joseph Dattilo

  4. hey buddy..I have successfully made the barebone circuit as above, I have removed the led and all that..because I dont need that on my chip..instead I will be interfacing this circuit with an ASK RF module 433Mhz transmitter. My first question is this chip would be placed somewhere and we are not allowed to use FTDI cable for giving Vcc. We need to use batteries. Can we use 3V/3.7V or 4.5V battery to power this chip.

    • I think this question was already answered via email, but if not the answer is yes. The Atmega328 can run safely between 3.3 and 5 volts from a battery. That said I would not recommend anything less than 4.3 volts with a 16 MHz crystal like the one that comes with the Bareduino kits. With a modified bootloader and an 8 MHz crystal you can drop that even lower toward the 3.3 volt range without any trouble. Operating with that low a voltage on a 16 MHz crystal however could cause system stability problems.

      Let me know how things go with the power source you choose, and good luck with the build.

  5. As a newcomer I am confused (easily done) the diagrams and the photos seem different. They are offset by one pin in each case. It could just be my imagination but can you confirm if either or both is correct.

    Thanks a lot

    Trevor

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