Arduino Code Flashing on ATmega8A

This repository explains how to flash Arduino sketches onto an ATmega8A microcontroller, either with or without a bootloader.

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🔧 Hardware Requirements

• ATmega8A microcontroller (DIP-28 or TQFP)
• USBasp programmer or Arduino UNO as ISP
• Optional: USB-to-TTL adapter (for uploading code after bootloader)
• 16 MHz crystal + 22pF capacitors (if using external crystal)
• Jumper wires, breadboard, power supply (5V)

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📌 Pin Connections (ISP Programming)

ATmega8A Pin	Function	Programmer Pin
Pin 7, 20	VCC	+5V
Pin 8, 22	GND	GND
Pin 1	RESET	RESET
Pin 17	MOSI	MOSI
Pin 18	MISO	MISO
Pin 19	SCK	SCK

👉 If using external clock: connect Pin 9 & 10 to 16MHz crystal + capacitors.

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🚀 Flashing Bootloader (Arduino IDE)

1. Install MiniCore in Arduino IDE Boards Manager.
2. Select:
   • Board: ATmega8
   • Clock: Internal 8 MHz (or 16 MHz if using external crystal)
   • Programmer: USBasp (or Arduino as ISP)
3. Click Tools → Burn Bootloader.

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💻 Uploading Arduino Sketch

• After bootloader is installed, connect via USB-to-TTL adapter:

USB-to-TTL	ATmega8A Pin
TXD	Pin 2 (RXD)
RXD	Pin 3 (TXD)
GND	GND
VCC	+5V
DTR	RESET (via 100nF capacitor)

Then upload sketches directly from Arduino IDE.

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🖥️ Uploading Without Bootloader (Direct HEX Flash)

You can also upload compiled code without bootloader using avrdude:

avrdude -c usbasp -p atmega8 -U flash:w:sketch.hex