Receiving a byte over UART in Embedded C - Mini Project: Build & Apply

Receiving a byte over UART

📖 Scenario: You are working on a small embedded device that communicates with other devices using UART (Universal Asynchronous Receiver/Transmitter). Your task is to write a simple program that receives one byte of data from the UART interface.

🎯 Goal: Build a program that sets up a variable to store the received byte, waits for the UART to have data ready, reads the byte from the UART data register, and then prints the received byte value.

📋 What You'll Learn

Create a variable to store the received byte

Create a variable to check the UART status register

Use a loop to wait until the UART receive buffer is full

Read the received byte from the UART data register

Print the received byte value

💡 Why This Matters

🌍 Real World

Embedded devices often communicate with sensors, other microcontrollers, or computers using UART. Receiving data correctly is essential for these devices to work.

💼 Career

Understanding UART communication is important for embedded systems engineers, firmware developers, and anyone working with microcontrollers.

1

DATA SETUP: Create a variable to store the received byte

Create a variable called received_byte of type unsigned char and initialize it to 0.

Embedded C

unsigned char received_byte = 0;  // Your code here

Need a hint?

Use unsigned char to store one byte of data.

2

CONFIGURATION: Create a variable to check UART status

Create a variable called uart_status of type unsigned char to hold the UART status register value.

Embedded C

unsigned char received_byte = 0;
unsigned char uart_status;  // Your code here

Need a hint?

This variable will be used to check if data is ready to read.

3

CORE LOGIC: Wait for data and read the byte from UART

Use a do-while loop to repeatedly read uart_status from UCSRA register and check if bit 7 (RXC) is set. When set, read the received byte from UDR register into received_byte.

Embedded C

unsigned char received_byte = 0;
unsigned char uart_status;

// Your code here

Need a hint?

Bit 7 (RXC) in UCSRA tells if data is ready. Use bitwise AND to check it.

4

OUTPUT: Print the received byte value

Use printf to print the text "Received byte: " followed by the value of received_byte as an unsigned integer.

Embedded C

unsigned char received_byte = 0;
unsigned char uart_status;

do {
    uart_status = UCSRA;
} while ((uart_status & (1 << 7)) == 0);

received_byte = UDR;

// Your code here

Need a hint?

Use printf("Received byte: %u\n", received_byte); to show the value.