UART and Interfacing with Arduino

Introduction to UART

• Definition: UART stands for Universal Asynchronous Receiver-Transmitter.
• Purpose: Used for serial communication.
• Transmission Protocol:
  • It is a two-wire transmission protocol:
  • One wire for transmission
  • One wire for reception.
• Data Format: Configurable data format and transmission speed.
• Synchronization: No clock signal is provided for synchronization.
• Speed Comparison: Slower than parallel communication but requires fewer bus interfaces.

Configuration of UART Before Transmission

• Both communicating devices must have the same transmission speed (Baud Rate).
• Settings:
  • Fix the data length between 5 to 9 bits.
  • Requires a start bit (1 bit) and a stop bit (1 or 2 bits).
• Encoding: Uses Non-Return to Zero (NRZ) encoding for data communication.
• Common Baud Rates: Examples include 9600, 115200.

UART Data Transmission Structure

• Data Format:
  • A typical data structure:
  • Start Bit: 1 bit
  • Data Bits: D1 to D7 (5 to 9 bits)
  • Parity Bit (optional)
  • Stop Bit: 1 or 2 bits

Interfacing Arduino UNO with UART

• Pins:
  • Tx (Transmit) and Rx (Receive) pins used for UART.
  • Additional power and ground pins for proper operation.

Example: Arduino UNO with Neo 6m GPS Module

• Connections:
  • Connect Tx of Neo 6m to Rx of Arduino and vice versa.
  • Follow the pin configurations from the Arduino to ensure correct functioning.

Arduino Code Snippet for UART Communication

#include <SoftwareSerial.h>
SoftwareSerial gpsSerial (4, 3); // RX = 4, TX = 3

void setup() {
    Serial.begin(9600);
    gpsSerial.begin(9600); // Start GPS module UART at 9600 baud
}

void loop() {
    while (gpsSerial.available()) {
        Serial.write(gpsSerial.read()); // Read GPS data and print to Serial Monitor
    }
}

• Example Output: GPS data in the NMEA format such as $GPRMC,015915.00, ...