The Serial Peripheral Interface (SPI) is a commonly used protocol in electrical systems for a variety of applications. This blog post will serve as a resource guide to good articles, app notes, and IC’s that use the SPI protocol.

What is the purpose of open-drain interrupts? Open-drain interrupts are used to communicate some type of indicator or flag back to the MCU. It signals the brains of system that something has happened to one or more peripheral devices in a design.

Input high voltage, input low voltage, output high voltage, output low voltage. Why do these terms matter, and how to design electrical systems with this electrical characteristics in mind.

A photo resistor is a sensor that changes resistance when exposed to light. Learn how to code an Arduino using this sensor.

This post contains links to various topics for I2C and is updated when new and valuable I2C resources are posted to the internet.

What does TCAL6416R mean? What is the difference between TCAL6416 and TCAL6416R? Why does a sticky reset matter?

This is a generic coding example of setting up an Arduino to write and read I2C

I2C controlled switches are used in various applications for same I2C address conflicts, separating bus capacitance, and data flow control.

Texas Instruments TCAL6416 I2C IO Expander is a widely capable device with several features useful for various electrical systems involving IO shortages.

Rise-time and fall-time are important electrical specs. Here is why they matter.

Open-drain circuits are common output stages used in various applications of electrical engineering.

What is I2C buffering? How is the TCA9517A used?