====== Standalone AVR Chip Prep w/ Arduino Bootloader ======

AVR Chips on the arduino uno come loaded with a bootloader to run the usb communication & 
arduino stdlib. This is how to go from a blank chip to a flashed chip.

===== Chip Initial Prep =====

Pin connections:
[{{ avr-programming-20260324-182624.png?300|Atmega328P DIP Pinout}}]
<code>
16MHz Crystal across PB6/PB7
connect 22pF bipolar caps from the crystal to ground:

                             GND
PB6 ----------|-------[22pF]--|
          [Crystal]           |
PB7 ----------|-------[22pF]--|

Pin R10k pullup to +5V
AVCC connected to +5V
also might be useful to have pwr indicator LED
</code>

===== Arduino as ISP Setup & Burning =====

  * Start by Loading ''File -> Examples -> 11.ArduinoISP -> ArduinoISP''
  * Connect seperate Arduino UNO board (hereafter called the programmer) to pc via usb.
  * Upload the ISP sketch to the programmer.
  * Install the [[https://github.com/MCUdude/MiniCore|MiniCore library]] and install the MiniCore boards
  * Wire the following connections from the programmer:

<code>
10 -> MOSI  (17)
11 -> MISO  (18)
12 -> SCK   (19)
13 -> RESET ( 1)
</code>
[{{ avr-programming-20260319-013254.png?300|Arduino as ISP wiring diagram}}]

  * Select the programmer method as ''Tools -> Programmer -> Arduino as ISP''
  * Select the ''Atmega328'' in ''Tools -> Board'' and make sure the variant based on the chip you have.
  * Set the clock to 16MHz external (or whatever you are using).
  * Burn the bootloader with ''Tools -> Burn Bootloader''

===== Programming with ISP =====

From the ISP dongle, make the connections to the chip

^ ISP Pin ^ Atmega Pin ^
| VCC     | VCC        |
| GND     | GND        |
| MOSI    | MOSI (17)  |
| MISO    | MISO (18)  |
| SCK     | SCK  (19)  |
| RST     | RESET (1)  |

Then upload the code with ''Sketch -> Upload using Programmer''.