According to this new resolution, people are encouraged to use the word 'Controller' in place of 'Master' and 'Peripheral' in place of 'Slave'.

Important Note: A new resolution is underway to improve the terminologies used in SPI communication by removing office words like 'Master' and 'Slave' while discussing SPI communication. To demonstrate SPI communication, we will control the master side LED by the push button at the slave side and vice versa using the SPI Serial communication protocol. Here one Arduino will act as Master and another one will act as Slave, two LEDs and push buttons will be connected to both the Arduino. We will use SPI Protocol for communication between two Arduinos. In this tutorial, we learn about the SPI protocol and how to use it in Arduino. There are many types of serial communication like UART, CAN, USB, I2C, and SPI communication. Serial communication is the process of sending data one bit at a time, sequentially, over a communication channel or bus.

There are many different types of communication protocols for wireless and wired communication, and the most commonly used communication technique is Serial Communication. A Microcontroller uses many different protocols to communicate with various sensors and modules.

Teensy wire library