The article explains what PWM is and why it is used to simulate analog output with digital signals. It covers cycles, period, frequency, duty cycle, how to calculate duty cycle and average output voltage, and shows an Arduino example that fades an LED using analogWrite.

This article explains what UART is, how it works, what baud rate and frames are, how start, data, parity and stop bits function, and where UART is used in practice.

This article explains what the SPI communication protocol is and how it works. It covers signals like MOSI, MISO, SCLK and CS, explains sending and receiving data, multiple peripheral configurations (regular and daisy-chain), and lists the main advantages, disadvantages and real-world uses of SPI.

This article explains what I2C is, how it works, how devices are addressed, why pull-up resistors are needed, and how to use and troubleshoot I2C in projects.

A Raspberry Pi I2C tutorial using the Qwiic ecosystem. It shows required hardware, how to enable I2C, connect a BME680 sensor and SSD1306 OLED, install tools/libraries, scan devices with i2cdetect, and run a Python example that reads temperature via pigpio and displays it on the OLED.