Week 4 : Embedded Programming

Overview

This week's assignment focused on understanding the fundamentals of embedded programming by studying microcontroller datasheets, writing embedded software, and interfacing output devices with a microcontroller. The primary objective was to gain practical experience in developing firmware, understanding hardware-software interaction, and implementing a working embedded application.

Assignment Tasks

• Study the microcontroller datasheet.
• Understand the architecture of the XIAO ESP32-C3.
• Develop and upload embedded firmware.
• Interface an LCD display with a microcontroller.
• Validate the program through practical testing.
• Document the programming workflow and learning outcomes.

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My contribution to the group assignment focused on studying the Seeed Studio XIAO ESP32-C3 microcontroller, understanding its datasheet, and exploring communication protocols such as UART, I²C, and SPI. I also worked on interfacing display modules using the I²C protocol and documented the programming workflow, hardware setup, and communication process. This activity helped me gain a deeper understanding of embedded system architecture and hardware-software integration.

The complete group assignment documentation, including experimental procedures, observations, and results from all team members, can be accessed through the Fab Academy Lab page linked below.

Through this collaborative exercise, I learned how different communication protocols are implemented in embedded systems and how development boards can be programmed to interact with external peripherals. The experience also strengthened my understanding of datasheet interpretation, circuit connections, and firmware development.

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For this week's assignment, I explored the datasheet of the Seeed Studio XIAO ESP32-C3 . Studying the datasheet helped me understand the microcontroller's architecture, pin configuration, communication interfaces, memory organization, power management features, and wireless capabilities. It provided a detailed overview of how a compact development board can integrate processing, connectivity, and I/O functionality within a small footprint. Reviewing the datasheet was an important first step before beginning any programming or hardware interfacing activities.

View XIAO ESP32-C3 Datasheet

Seeed Studio XIAO ESP32C3 – Key Datasheet Highlights

• 32-bit RISC-V single-core processor at 160 MHz
• Wi-Fi (2.4 GHz) and Bluetooth 5.0 (BLE)
• 400 KB SRAM + 4 MB Flash memory
• 11 multifunctional I/O pins
• 1× UART, 1× I2C, 1× SPI, 4× ADC (12-bit)
• USB Type-C for programming and power
• Ultra-small form factor: 21 x 17.5 mm
• Supports low-power sleep modes
• Built-in RGB LED and reset button
• Ideal for IoT, wearables, and wireless projects

Comparison: Arduino Uno vs Seeed Studio XIAO ESP32C3

Feature	Arduino Uno	XIAO ESP32C3
Processor	ATmega328P (8-bit AVR @ 16 MHz)	ESP32-C3 (32-bit RISC-V @ 160 MHz)
Wi-Fi/Bluetooth	None	Wi-Fi + BLE 5.0
Flash Memory	32 KB	4 MB
SRAM	2 KB	400 KB
I/O Pins	14 Digital, 6 Analog	11 Multipurpose I/Os
ADC Resolution	10-bit	12-bit
USB Type	USB-B	USB-C
Power Consumption	Higher	Very Low (Supports sleep modes)
Form Factor	Large (68.6 x 53.4 mm)	Ultra-compact (21 x 17.5 mm)
Programming Language	Arduino (C++)	Arduino (C++), MicroPython
Cost & Availability	Widely available, low cost	Compact, modern, affordable

Arduino Uno R3 Technical Datasheet

Board Specifications

Microcontroller	ATmega328P
Operating Voltage	5V
Input Voltage	7-12V (recommended)
Digital I/O Pins	14 (6 provide PWM output)
Analog Input Pins	6
Flash Memory	32 KB (0.5 KB used by bootloader)
SRAM	2 KB
EEPROM	1 KB
Clock Speed	16 MHz
Dimensions	68.6mm × 53.4mm

Power Specifications

Power Sources

• USB connection (5V)
• DC power jack (7-12V)
• Vin pin (7-12V)

Current Ratings

• 5V pin: 500mA max
• 3.3V pin: 50mA max
• I/O pins: 20mA per pin (40mA max total)

Additional Resources

• Schematic Diagram (PDF)
• Arduino IDE Download
• Official Product Page

Communication Protocols in Embedded Systems

Microcontrollers rarely work alone. In most embedded systems, they communicate with sensors, displays, memory modules, and other controllers through standardized communication protocols. These protocols define how information is transmitted and received between devices. During this week's assignment, I explored three commonly used communication methods: UART, I²C, and SPI.

Protocol	Lines Required	Speed	Complexity	Applications
UART	TX, RX	Moderate	Easy	Serial Monitor, PC Communication
I²C	SDA, SCL	Moderate	Medium	OLED Displays, Sensors
SPI	MOSI, MISO, SCK, CS	High	Medium	Displays, SD Cards, Memory Devices

UART Communication

UART (Universal Asynchronous Receiver Transmitter) is one of the simplest communication protocols used in embedded systems. It transfers data through two lines: TX (Transmit) and RX (Receive). Since UART does not require a clock signal, it is commonly used for serial monitoring, debugging, and communication between microcontrollers and computers.

SPI Communication

SPI (Serial Peripheral Interface) is a high-speed communication protocol that uses separate lines for clock and data transfer. It provides faster communication compared to I²C but requires more wiring. SPI is commonly found in TFT displays, SD cards, flash memory devices, and high-speed peripherals.

Understanding I²C Communication

For this assignment, I selected an OLED display that communicates using the I²C protocol. I²C, which stands for Inter-Integrated Circuit, is a two-wire communication standard developed to simplify communication between electronic devices.

Only two signal lines are required:

• SDA – Serial Data Line
• SCL – Serial Clock Line

The microcontroller acts as the master device while the OLED display behaves as the slave device. Data is transferred over the SDA line while synchronization is maintained using the SCL clock signal.

One of the major advantages of I²C is that multiple devices can share the same communication bus, reducing the number of wires required in a project.

s Comparison of UART, I²C, and SPI communication protocols.

Reference Videos

The following videos helped me understand communication protocols such as UART, I²C, and SPI, as well as the process of interfacing an OLED display with Arduino. These resources provided additional insight into the concepts explored during this assignment.

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1. I²C Communication Explained

2. UART vs SPI vs I²C Comparison

Reference Video: SSD1306 OLED Display with Arduino

The following tutorial provides a practical introduction to interfacing an SSD1306 OLED display with Arduino using the I²C communication protocol. It covers hardware connections, library installation, code explanation, and display testing, making it a useful reference while performing this assignment.

Reference tutorial demonstrating SSD1306 OLED display interfacing with Arduino using I²C communication.

Basic I²C communication architecture showing SDA and SCL connections.

Online Electronics Simulators

Online electronics circuit simulators are web-based tools that allow users to design, simulate, and test electronic circuits virtually—without any physical components. These platforms are especially useful for beginners, educators, and hobbyists, as they offer a low-risk environment to learn and experiment.

Key Features

• Drag-and-drop interface for adding components like resistors, transistors, ICs, microcontrollers, etc.
• Real-time simulation of voltages, currents, and logic states.
• Breadboard and schematic views for clearer design understanding.
• Code integration for microcontrollers (Arduino, ESP32, etc.).
• Often cloud-based, allowing projects to be saved and shared online.

Different Online Simulators

Simulator Name	Features	Ideal For	Download Link
Tinkercad Circuits	Arduino simulation, breadboard view, code editor	Beginners, students	TinkerCAD
Falstad Circuit Simulator	Analog and digital simulation, waveform visualization	Intermediate users	Falstad Circuit Simulator
EasyEDA	PCB design + simulation, schematic editor	PCB designers	EasyEDA
CircuitVerse	Digital logic circuit simulator	Digital electronics learners	CircuitVerse
Multisim Live	SPICE simulation, schematic design	Engineering-level projects	Multisim Live

Introduction to TinkerCAD

TinkerCAD is a free, easy-to-use app for 3D design, electronics, and embedded coding. It's used by designers, hobbyists, teachers, and kids, for creating simple 3D models and circuits.

Websearch for TinkerCAD

Interface of TinkerCAD

TinkerCAD is not just only for designing circuits, we can also use it to design 3D models and many inbuilt examples are available in the website

TinkerCAD

Differnet usage of TinkerCAD

Let's Create a new circuit for our Assignment

Click on the Circuits button below

Step 1:

Navigation bar in KiCAD

1. Clipboards
2. Rotation of components
3. Delete
4. Undo
5. Redo

Navigations

Control Bars

Components Selection Area

Various Display availability in TinkerCAD

Step 2:

For this Week, we are gonna work on LCD Display so Choosing 16*2 LCD display

Various Display availability in TinkerCAD

Arduino LCD 16x2 Display Guide

This guide explains how to display "Welcome to Fab Academy" on a 16x2 LCD using an Arduino and the Adafruit_LiquidCrystal library.

1. Hardware Requirements

• Arduino Board (Uno, Mega, etc.)
• 16x2 LCD Display
• I2C Module (PCF8574T)
• Connecting Wires
• External Power Source (if needed)

2. Wiring Instructions

LCD Pin	Arduino Pin
VCC	5V
GND	GND
SDA	A4 (Uno) / 20 (Mega)
SCL	A5 (Uno) / 21 (Mega)

3. Arduino Code

            #include <Adafruit_LiquidCrystal.h>
            int seconds = 0; 
        Adafruit_LiquidCrystal lcd_1(0);
    
        void setup() {
            lcd_1.begin(16, 2);
            lcd_1.print("Welcome to Fab");
            lcd_1.setCursor(0, 1);
            lcd_1.print("Academy");
            delay(2000);
            lcd_1.clear();
            }
    
        void loop() {
            lcd_1.setCursor(0, 0);
            lcd_1.print("Time (sec): ");
            lcd_1.setCursor(11, 0);
            lcd_1.print(seconds);
        
            lcd_1.setBacklight(1);
            delay(500);
            lcd_1.setBacklight(0);
            delay(500);
        
            seconds++;
        }
        

Arduino Code Explanation – LCD with Timer

Libraries and Variables

#include <Adafruit_LiquidCrystal.h>
int seconds = 0;
Adafruit_LiquidCrystal lcd_1(0);
  

• #include <Adafruit_LiquidCrystal.h>: Adds the library needed to control the LCD using I2C or other interfaces.
• int seconds = 0;: Creates a variable to count and display time in seconds.
• Adafruit_LiquidCrystal lcd_1(0);: Creates an LCD object called lcd_1. The parameter 0 is used when only one LCD is connected.

setup() Function

void setup() {
  lcd_1.begin(16, 2);
  lcd_1.print("Welcome to Fab");
  lcd_1.setCursor(0, 1);
  lcd_1.print("Academy");
  delay(2000);
  lcd_1.clear();
}
  

• lcd_1.begin(16, 2);: Initializes the LCD with 16 columns and 2 rows.
• lcd_1.print("Welcome to Fab");: Prints text on the first line of the LCD.
• lcd_1.setCursor(0, 1);: Moves the cursor to the beginning of the second line.
• lcd_1.print("Academy");: Prints "Academy" on the second line.
• delay(2000);: Waits for 2 seconds (2000 milliseconds).
• lcd_1.clear();: Clears the LCD screen.

loop() Function

void loop() {
  lcd_1.setCursor(0, 0);
  lcd_1.print("Time (sec): ");
  lcd_1.setCursor(11, 0);
  lcd_1.print(seconds);

  lcd_1.setBacklight(1);
  delay(500);
  lcd_1.setBacklight(0);
  delay(500);

  seconds++;
}
  

• lcd_1.setCursor(0, 0);: Places the cursor at the beginning of the first line.
• lcd_1.print("Time (sec): ");: Displays the label "Time (sec):" on the LCD.
• lcd_1.setCursor(11, 0);: Moves cursor to the 12th column of the first line.
• lcd_1.print(seconds);: Displays the current value of seconds.
• lcd_1.setBacklight(1);: Turns ON the LCD backlight.
• delay(500);: Waits for half a second.
• lcd_1.setBacklight(0);: Turns OFF the LCD backlight.
• delay(500);: Waits again for half a second, creating a blinking effect.
• seconds++;: Increases the second counter by 1 every second.

What This Code Does

This Arduino code displays a welcome message ("Welcome to Fab Academy") for 2 seconds, then starts counting time in seconds. The LCD backlight blinks every 0.5 seconds to create a visual effect while the time increases.

Learning Summary

• Understand the basics of Arduino and its components.
• Understand about the Xiao - Seeed Studio Esp32C3
• Learn how to use the LiquidCrystal library to control an LCD screen.
• Implement a simple timer using the LCD screen.

OLED Display Experiment

After understanding the communication protocols and validating the circuit in TinkerCAD, I implemented the project physically using an Arduino Uno and a 0.96-inch SSD1306 OLED display. The objective was to establish I²C communication and display custom text on the OLED screen. This experiment helped me understand how embedded systems communicate with external display devices and present information in real time.

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OLED Working Principle

OLED stands for Organic Light Emitting Diode. Unlike traditional LCD displays, OLED displays do not require a backlight because each pixel emits its own light. This results in better contrast, lower power consumption, and excellent visibility. The SSD1306 OLED used in this assignment has a resolution of 128 × 64 pixels and communicates using the I²C protocol through only two signal lines: SDA and SCL.

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Circuit Connections

The OLED display was connected to the Arduino Uno using the I²C communication interface. The connections used are shown below.

OLED Pin	Arduino Uno Pin	Function
VCC	5V	Power Supply
GND	GND	Ground
SDA	A4	Serial Data Line
SCL	A5	Serial Clock Line

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Libraries Used

To communicate with the OLED display, the following Arduino libraries were used:

Library	Purpose
Wire.h	Provides I²C communication support.
Adafruit_GFX.h	Provides graphics functions such as text, lines, and shapes.
Adafruit_SSD1306.h	Controls the SSD1306 OLED display module.

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Code Explanation

The program begins by including the required libraries for I²C communication and OLED control. The display object is then initialized with a resolution of 128 × 64 pixels. Inside the setup function, communication with the OLED display is established and the display is initialized. In the main loop, the display buffer is cleared, the cursor position is set, and the text "WELCOME TO ACADEMY!" is written to the screen. Finally, the display buffer is updated so that the text becomes visible on the OLED screen.

Arduino IDE showing the SSD1306 OLED display program.

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Hardware Demonstration

After successfully uploading the program, the OLED display initialized correctly and displayed the programmed text. The experiment verified successful I²C communication between the Arduino Uno and the SSD1306 OLED display module.

Physical implementation of the OLED display experiment using Arduino Uno and SSD1306 OLED module.

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Learning Outcome

Through this experiment, I gained practical experience in interfacing an OLED display with a microcontroller using the I²C communication protocol. I learned how external libraries simplify hardware interaction, how display modules are initialized, and how embedded software can be used to present information on graphical displays. This activity strengthened my understanding of hardware-software integration in embedded systems.

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Downloads and References

The following resources were used throughout this week's Embedded Programming assignment. These references include the microcontroller documentation, development board documentation, and the Arduino source code used for the OLED display experiment.

Resource	Description	Link
Arduino Uno Datasheet	Official technical documentation for the Arduino Uno development board.	View Datasheet
XIAO ESP32-C3 Documentation	Hardware specifications, pinout, and programming guide.	View Documentation
OLED Display Source Code	Arduino sketch used to interface the SSD1306 OLED display using I²C communication.	Download Code

Files Included

• Arduino Uno Datasheet
• XIAO ESP32-C3 Documentation
• SSD1306 OLED Arduino Program (.ino)
• Embedded Programming Assignment Documentation

These resources can be used to reproduce the experiment, understand the hardware architecture, and further explore embedded system development using Arduino and ESP32-based platforms.

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