ATMEGA328P-PU

The ATMega328P-PU chip is an Atmel & Arduino Uno workhorse. Running from 5 volts max, this chip alone will control nearly 100% of your projects just like an Arduino Uno does but without the bulk. You only need a minimum number of components to get started.

LM7805C 5V Voltage Regular. Very important to make sure your ATMega only receives the 5 volts it needs.

2 100nF capacitors for voltage stabilization, both before and after the LM7805C

16MHz Crystal which is used for timing. Without it you are limited to the onboard 8MHz crystal

2 22Pf capacitors to bridge the crystal with ground

1 10K resistor for the pull-down on pin 1 reset of the ATMega

1 Tactile Push Button to provide you the ability to reset the chip when needed

2 220RΩ resistors for the power LED and pin 13 LED

2 LEDs, one red and one green like in my project or any other color that you have lying around. These mostly serve to let you know that things are running like they should, like with the blink sketch, which will blink the pin 13 LED once every second. But they are optional in case you want to save those extra few mA.

 

As you can see from the images, I used 4 AA batteries which provide 6 volts. You could use a 9Volt batter instead here but it will be less efficient when going through the LM7805C voltage regulator. The more work it has to do to keep your voltage down to the required 5 will be spent on like heat and loss so I suggest the 4 AAs, a USB power source or perhaps a 5 Volt AC to DC adaptor so you can have continuous power from the wall socket.

ATMega328 Standard Circuit Layout

ATMega328 Standard Circuit Layout Closeup