Embedded Programming: ATmega328P

The Arduino IDE hides what matters. Writing to DDRx, PORTx, and PINx directly teaches you how microcontrollers actually work. This knowledge transfers to every chip you will ever use.

Every lesson references the ATmega328P datasheet directly. You learn to read register descriptions, timing diagrams, and electrical specs. This is the skill that separates hobbyists from engineers.

The Arduino IDE’s Blink sketch compiles to 924 bytes of flash. Our Morse code beacon does more and uses under 428 bytes. Bare metal includes only what you write, with no hidden timer setup, pin lookup tables, or runtime overhead.

Each lesson produces something purposeful: a temperature logger, a weather station, a reaction time tester. You build things worth keeping while learning each peripheral.

An Arduino Nano costs under 5 USD. A breadboard and a handful of components is all you need. No expensive dev kits, no debugger required to start. You can begin today.

AVR Toolchain and Bare-Metal Setup. Install avr-gcc, avrdude, and write your first Makefile. Build a Morse code beacon that blinks your name on an LED. First contact with register-level programming. Build: Morse code beacon. Parts: Nano, breadboard, LED, 220R resistor.

GPIO Registers and Digital I/O. Master DDRx, PORTx, PINx registers and bit manipulation. Build an electronic dice with button input and random LED patterns using a simple LFSR. Build: Electronic dice. Parts: 3 more LEDs, push button, 10K resistor.

Timer/Counter Fundamentals. Explore Timer0, Timer1, and Timer2 in Normal, CTC, and PWM modes. Prescalers, overflow interrupts, output compare. Build a tunable tone generator with precise frequencies. Build: Tunable tone generator. Parts: Piezo buzzer.

Interrupts and Event-Driven Design. Configure INT0/INT1, pin-change interrupts, and timer interrupts. Learn ISR design patterns, volatile variables, and atomic blocks. Build a reaction time tester. Build: Reaction time tester. Parts: Reuse existing.

UART Serial Communication. Set up the USART peripheral from scratch: baud rate calculation, TX/RX registers, ring buffers, printf redirect. Build a temperature logger that streams CSV to your PC. Build: Temperature logger with CSV export. Parts: 10K thermistor.

SPI Protocol and Peripheral Interfacing. Master the SPI peripheral: SPCR, SPSR, clock polarity/phase, master/slave select. Write an SSD1306 OLED driver from scratch. Build a real-time clock display. Build: OLED clock display. Parts: SSD1306 OLED (SPI).

I2C Bus and Sensor Integration. Implement I2C (TWI) communication: start/stop conditions, addressing, ACK/NACK, multi-byte reads. Interface a BME280 for temperature, humidity, and pressure on your OLED. Build: Mini weather station. Parts: BME280 module.

ADC and Analog Signal Acquisition. Configure the 10-bit ADC: reference voltage selection, channel multiplexing, free-running vs single conversion, noise reduction techniques. Build a light-tracking indicator. Build: Light-tracking indicator. Parts: 2 LDRs, 2 resistors.

Power Management and Watchdog. Explore all sleep modes (Idle through Power-down), watchdog timer configuration, BOD disable, EEPROM storage, and wakeup sources. Build a battery-powered door open alert with persistent event counting. Build: Battery-powered door alert. Parts: 2xAA battery holder, reed switch.

Integrated Stepper Motor and Motion Control. Combine every peripheral from the course into a single-axis CNC-style controller. Parse G-code over UART, generate step pulses with Timer1, home with a limit switch interrupt, jog with an ADC potentiometer, and store calibration in EEPROM. Build: Single-axis stepper controller. Parts: A4988 driver, NEMA 17 motor, limit switch, 10K pot, 12V supply.