Serial Communication with Arduino - The details!

Summary

This video explains the concept of serial communication, breaking down how data is transmitted one bit at a time between devices like microcontrollers. It focuses on the simplest method, TTL serial communication, and the role of USART (Universal Synchronous/Asynchronous Receiver/Transmitter) in this process. Viewers will learn about important components like start bits, data frames, optional parity bits, stop bits, and the significance of baud rates. Using a practical example, the video demonstrates how the Arduino handles serial communication, with a special focus on error-checking and the role of common baud rates like 9,600.

Takeaways

• 😀 Serial communication transmits data one bit at a time between devices.
• 😀 USB is a form of serial communication, and the 'USB' stands for Universal Serial Bus.
• 😀 Arduino supports various serial communication protocols like SPI, I2C, and USART.
• 😀 A USART (Universal Synchronous/Asynchronous Receiver/Transmitter) is used to enable serial communication in devices.
• 😀 The key distinction in USART communication is between synchronous (with clock) and asynchronous (no clock) protocols.
• 😀 Asynchronous protocols use a baud rate to synchronize data transmission, which must be agreed upon by both sender and receiver.
• 😀 TTL (Transistor-Transistor Logic) serial communication is a straightforward form of asynchronous serial communication used in Arduino.
• 😀 Serial communication begins with a start bit, followed by data bits, an optional parity bit for error checking, and ends with a stop bit.
• 😀 Parity bits are used for error checking, ensuring that the number of 1's in the data frame (including the parity) is either even or odd.
• 😀 Baud rate controls the speed of data transfer, and both devices must agree on the same baud rate for successful communication.
• 😀 9,600 baud is a conventional speed for Arduino communication, but baud rates can be adjusted to suit specific needs, as long as both devices match.

Q & A

What is serial communication?

Serial communication is a method of transmitting data one bit at a time over a single channel. It's commonly used in devices like Arduino for communication between the microcontroller and other hardware components.

How does serial communication work?

Serial communication works by sending a start bit to signal the beginning of a transmission, followed by the data frame (usually 8 bits), an optional parity bit for error checking, and a stop bit to indicate the end of the transmission.

What is USART and how does it relate to serial communication?

USART stands for Universal Synchronous/Asynchronous Receiver/Transmitter. It's a hardware component that helps convert data from parallel format to serial format and vice versa. It allows devices like Arduino to communicate via TTL serial communication.

What does TTL stand for, and why is it used in serial communication?

TTL stands for Transistor-Transistor-Logic. It's a logic level used in serial communication, particularly in TTL serial, where the logic levels for transmitting and receiving data are defined by high and low voltages, typically 5V and 0V.

What is the significance of the start bit in serial communication?

The start bit is used to signal the beginning of a transmission. It tells the receiver that a message is about to be sent, and it is always set to a low voltage level to mark the start of the data frame.

Why are bits sent in reverse order in serial communication?

In serial communication, bits are sent in reverse order because the protocol follows the 'least significant bit first' rule. This convention has been in place for historical and technical reasons, though it can be confusing at first.

What is a baud rate and why is it important in serial communication?

The baud rate defines the speed at which data is transmitted. It is the number of bits sent per second. Both the sender and receiver need to use the same baud rate to ensure data is transmitted and received correctly.

What is the purpose of the parity bit in serial communication?

The parity bit is used for error checking. It ensures the integrity of the data frame by making the total number of 1s in the frame either even (even parity) or odd (odd parity). If the number doesn't match the expected parity, the receiver knows the data may be corrupted.

How does the baud rate affect the transmission of data?

The baud rate determines how quickly bits are transmitted. A higher baud rate allows faster transmission but may cause errors if the sender and receiver aren't synchronized. A lower baud rate ensures reliability but reduces speed.

Why is 9600 baud rate commonly used in Arduino communication?

9600 baud is a widely accepted convention in Arduino projects because it provides a balance between speed and reliability. It’s sufficient for most basic communication tasks and is supported across many devices, making it a standard choice.