Ulima: week 4

Development Boards & Microcontrollers

Since it was our first time reading a microcontroller datasheet, our instructor gave us a quick explanation using the pin diagram (pinout) of the Raspberry Pi Pico 2 W as an example. From that, we learned how to interpret what each label means, how to identify the function of each pin, and how to read this type of schematic.

All development boards together — **All boards reviewed this week**Left to right: ESP32, Arduino R4, Arduino R3 (top row) — Seeed Studio XIAO, Arduino Nano, Pico 2W (bottom row).

What is a Development Board?

A development board is a complete electronic platform designed to help prototype, test, and program embedded systems easily. It includes a microcontroller as its main brain, along with voltage regulators, USB interface, communication ports, buttons, LEDs, and sometimes wireless modules.

What is a Microcontroller?

A microcontroller is a small integrated circuit that acts as the brain of an embedded system. It contains a processor (CPU), memory, input/output pins, and communication interfaces all inside a single chip.

ATmega328P microcontroller chip — **ATmega328P — bare microcontroller chip**The actual IC that powers both the Arduino UNO R3 and Nano. An Atmel (now Microchip) 8-bit AVR chip in TQFP package.

Fab Academy ULima — explore the full group assignment documentation on the official page:
fabacademy.org/2026/labs/ulima/ ↗

01

Raspberry Pi Pico 2 W

ARM Cortex-M33 · RP2350 · dual-core

**Raspberry Pi Pico pinout diagram**Color-coded pin reference for Pico 1 and Pico 2. Shows GPIO, ADC, I2C, SPI, UART, power, and debug pins.

The Raspberry Pi Pico 2 W is a development board with integrated WiFi, which allows it to be used in IoT projects. The board operates at 3.3V and supports SPI, I2C, and UART communication protocols.

MCU — RP2350

Architecture	ARM Cortex-M33 (dual-core)
Frequency	Up to 150 MHz
SRAM	520 kB
Flash	External (~4 MB)
ADC	12-bit
PWM	16 channels
PIO blocks	2 programmable I/O
Total Pins	40 (up to 30 GPIO)

Wireless — CYW43439

WiFi	802.11 b/g/n (2.4 GHz)
Bluetooth	BLE 5.2
Operating Voltage	3.3V
I2C / SPI / UART	2 / 2 / 2 buses

Workflow Chain

01
Write code
In C/C++ (official SDK) or MicroPython from VS Code or Thonny.
02
Compile
ARM GCC compiler translates the code into RP2350 instructions.
03
Generate binary
A .uf2 file ready to upload is produced.
04
Flash
Press BOOTSEL + USB — Pico appears as a storage drive, drag the .uf2.
05
Execute
The board restarts automatically and runs the program.
06
Monitor
View results via VS Code or Thonny serial monitor.

Toolchain

Tool	Purpose
Pico SDK	Official library to access RP2350 pins and functions
ARM GCC	Compiles code for the Cortex-M33 processor
CMake + Make	Organizes and builds the project
UF2 Format	Firmware file loaded via USB without extra hardware
VS Code + Pico Ext.	Recommended IDE; configures and compiles with one click
Thonny	MicroPython IDE; simpler and more direct
OpenOCD / SWD	Advanced debugging using a second Pico as debugger

02

Arduino UNO R4 WiFi

ARM Cortex-M4 · R7FA4M1AB3CFM

**Arduino UNO R4 WiFi pinout**Full pin reference showing digital, analog, I2C, SPI, UART, DAC, and ESP32-S3 header pins with color-coded legend.

The Arduino UNO R4 WiFi is an upgraded version of the classic UNO platform designed for embedded programming, rapid prototyping, and IoT applications. It integrates a powerful 32-bit microcontroller and a WiFi/Bluetooth module.

MCU — R7FA4M1AB3CFM

Architecture	32-bit ARM Cortex-M4
Flash	256 kB
SRAM	32 kB
Data Flash	8 kB (EEPROM)
ADC	14-bit
DAC	Up to 12-bit
CAN bus	Yes
DMAC	4 channels

Wireless — ESP32-S3-MINI-1

WiFi	2.4 GHz 802.11 b/g/n
Bluetooth	BLE 5
SRAM	512 kB
ROM	384 kB
Voltage	3.3V (logic translator)

Workflow Chain

01
Write code
In C/C++ from the Arduino IDE (called a "sketch").
02
Compile
Arduino IDE uses ARM GCC to translate code for the Cortex-M4.
03
Generate binary
A .hex or .bin file ready to upload is produced.
04
Flash
Loaded directly via USB with one click from the IDE.
05
Execute
The board restarts automatically and runs the program.
06
Monitor
Results visible in the Arduino IDE Serial Monitor.

Toolchain

Tool	Purpose
Arduino IDE	Main environment: editor, compiler, and uploader in one
ARM GCC	Compiles C/C++ code for the Cortex-M4 processor
Arduino Core (Renesas)	Official libraries and drivers for all pins and modules
USB Bootloader	Loads programs directly via USB without extra hardware
WiFiS3 Library	Official library to control the ESP32-S3 module from code
VS Code + PlatformIO	Advanced alternative with more control over compilation

03

Arduino UNO R3

8-bit AVR · ATmega328P

**Arduino UNO R3 pinout**Full pin reference — digital, analog, SPI, I2C, UART, power, and built-in LED pins labeled with port names.

The Arduino UNO R3 is one of the most popular development boards for learning embedded systems. It is widely used in education and beginner projects to control LEDs, sensors, motors, and other electronic components.

MCU — ATmega328P

Architecture	8-bit AVR
Frequency	16 MHz
Flash	32 kB
SRAM	2 kB
EEPROM	1 kB
ADC	10-bit
Digital Pins	14
Analog Inputs	6
PWM	6 channels

Workflow Chain

01
Write code
In C/C++ from the Arduino IDE (called a "sketch").
02
Compile
AVR-GCC translates code to instructions for the 8-bit ATmega328P.
03
Generate binary
A .hex file ready to upload is produced.
04
Flash
AVRDUDE communicates with the bootloader via USB and writes the .hex to Flash.
05
Execute
The board restarts automatically and runs the program.
06
Monitor
Results visible in the Arduino IDE Serial Monitor.

Toolchain

Tool	Purpose
Arduino IDE	Main environment: editor, compiler, and uploader in one
AVR-GCC	Compiles C/C++ code for the 8-bit AVR architecture
AVRDUDE	Transfers the .hex to the chip via USB and bootloader
Bootloader (pre-flashed)	Allows loading programs via USB without external hardware
Arduino Core Libraries	Libraries for pins, ADC, timers, and UART
Serial Monitor	Displays program results in real time

04

Seeeduino XIAO nRF52840

ARM Cortex-M4F · nRF52840

XIAO nRF52840 board — **Seeed Studio XIAO nRF52840 — board**Tiny form factor with USB-C, onboard BLE antenna, and RST button. Fits directly on a breadboard.

**XIAO nRF52840 pinout**Pin reference showing digital, analog, I2C, SPI, UART, power, and GND — color coded by function type.

The Seeeduino XIAO nRF52840 is a compact and powerful development board designed for IoT and Bluetooth applications. Despite its small size, it integrates wireless communication and advanced low-power features — ideal for wearables and battery-powered devices.

MCU — nRF52840

Architecture	32-bit ARM Cortex-M4F
Flash	1 MB
RAM	256 kB
ADC	12-bit
Bluetooth	BLE 5.0
USB	Full-speed USB 2.0
Digital Pins	Up to 14

Workflow Chain

01
Write code
In C/C++ (Arduino IDE with Seeed nRF52 package), MicroPython, or CircuitPython.
02
Compile
ARM GCC translates code for the Cortex-M4F at 64 MHz.
03
Generate binary
A .hex or .uf2 file ready to upload is produced.
04
Flash
Loaded via USB-C bootloader. Double-click reset activates storage mode if unresponsive.
05
Execute
The board restarts automatically and runs the program.
06
Monitor
Results visible in the Arduino IDE Serial Monitor.

Toolchain

Tool	Purpose
Arduino IDE	Main environment: editor, compiler, and uploader
ARM GCC	Compiles C/C++ code for the Cortex-M4F at 64 MHz
Seeed nRF52 Boards	Official library for BLE and low-power functions
Seeed nRF52 mbed	Library for TinyML and advanced sensors
UF2 Bootloader	Loads program via USB-C without external programmer
SWD + JLink	Advanced on-chip debugging during execution

05

ESP32 (ESP32-WROOM)

Xtensa LX6 · dual-core · 240 MHz

ESP32 DEVKIT board — **ESP32 DEVKIT V4 — board**ESP32-WROOM-32 module on a DevKit PCB. USB-C connector, EN and BOOT buttons visible at the bottom.

**ESP32-WROOM pinout diagram**Full pin reference with GPIO, ADC, DAC, SPI, I2C, UART, touch, RTC, and PWM capabilities annotated.

The ESP32 development board is designed for IoT and wireless applications. It integrates a powerful dual-core processor and built-in WiFi and Bluetooth, widely used for smart devices, home automation, and wireless control systems.

MCU — Xtensa LX6

Architecture	Xtensa LX6 (dual-core)
Frequency	Up to 240 MHz
SRAM	520 kB
Flash	External (~4 MB)
ADC	12-bit
DAC	2× 8-bit
GPIO	Up to 34 pins
SPI / I2C / UART	4 / 2 / 3 buses
WiFi + BT	Integrated (classic + BLE)

Workflow Chain

01
Write code
In C/C++ (Arduino IDE with ESP32 Core or ESP-IDF) or MicroPython.
02
Compile
Xtensa GCC translates code for the dual-core Xtensa LX6 at 240 MHz.
03
Generate binary
A .bin file ready to load into external Flash is produced.
04
Flash
esptool.py transfers the binary via USB. May require pressing BOOT during upload.
05
Execute
The board restarts automatically and runs the program.
06
Monitor
Results visible in the Arduino IDE or ESP-IDF Serial Monitor.

Toolchain

Tool	Purpose
Arduino IDE + ESP32 Core	Accessible environment with WiFi, BT, and dual-core support
Xtensa GCC	Compiles C/C++ for the dual-core Xtensa LX6 at 240 MHz
esptool.py	Official Espressif tool to load firmware via USB
ESP-IDF	Professional framework with full chip access and FreeRTOS
FreeRTOS	Integrated real-time OS; tasks can run on both cores simultaneously
VS Code + PlatformIO	Advanced alternative compatible with Arduino and ESP-IDF

06

Arduino Nano

8-bit AVR · ATmega328P · compact

**Arduino Nano pinout**Full pin reference — digital, analog (8 inputs vs 6 on UNO), SPI, I2C, UART, power, and LED pins labeled.

The Arduino Nano offers similar functionality to the UNO but in a much smaller form factor. Although both boards share the same microcontroller, the Nano has 8 analog inputs (vs 6 on the UNO) and fits directly on a breadboard.

MCU — ATmega328P

Architecture	8-bit AVR
Frequency	16 MHz
Flash	32 kB
SRAM	2 kB
EEPROM	1 kB
ADC	10-bit
Digital Pins	14
Analog Inputs	8 (vs 6 on UNO)
USB	Mini / Micro USB

Uses the same workflow as the UNO R3 since it shares the ATmega328P microcontroller. Code is written in the Arduino IDE, AVR-GCC compiles it to a .hex file, and AVRDUDE loads it via USB through the bootloader.

07

Development Board Comparison

Side-by-side summary of all boards reviewed during the group assignment.

Feature	UNO R3	Nano	UNO R4 WiFi	ESP32	Pico 2 W	XIAO nRF52840
Main MCU	ATmega328P	ATmega328P	R7FA4M1 (ARM M4)	Xtensa LX6	RP2350	nRF52840
Architecture	8-bit AVR	8-bit AVR	32-bit Cortex-M4	32-bit Xtensa (dual)	32-bit Cortex-M33 (dual)	32-bit Cortex-M4F
Clock Speed	16 MHz	16 MHz	48 MHz	240 MHz	150 MHz	64 MHz
Flash	32 kB	32 kB	256 kB	~4 MB	~4 MB	1 MB
SRAM	2 kB	2 kB	32 kB	520 kB	520 kB	256 kB
ADC	10-bit	10-bit	14-bit	12-bit	12-bit	12-bit
DAC	No	No	12-bit	2× 8-bit	No	No
WiFi	No	No	Yes	Yes	Yes	No
Bluetooth	No	No	BLE 5	Classic + BLE	BLE 5.2	BLE 5.0
Voltage	5V	5V	5V	3.3V	3.3V	3.3V
Low Power	No	No	No	Deep sleep	Dormant mode	Ultra low power
Price (approx.)	~$5	~$4	~$27	~$8	~$7	~$10
Best For	Education basics	Compact projects	IoT intermediate	IoT advanced	IoT WiFi connected	Wearables / BLE

Final Decision

Having reviewed all available microcontrollers, the choice was to work with the ESP32 DEVKIT V4 with the ESP-WROOM-32 processor, programmed using Thonny. Its dual-core architecture, integrated WiFi and Bluetooth, high speed (240 MHz), and generous memory make it the most versatile board for the type of projects planned.

Individual Reflections

What each team member learned from this week's assignment.

Nicolas

During the group assignment, I learned that reading a microcontroller datasheet is essential to understand the real capabilities and limitations of each board. I understood how factors such as architecture, clock frequency, memory, voltage logic, and communication protocols influence board selection for different embedded applications. This process also helped me distinguish between a development board and the microcontroller it contains, and improved my ability to compare platforms using technical information in a more objective and engineering-based way.

Micaela

This week I learned how to read and interpret a pinout diagram for the first time, which helped me understand what each pin does on a board before writing any code. Comparing the different toolchains made it clear how much the development experience varies between boards — from the simplicity of the Arduino IDE to the more flexible ESP-IDF. I also realized that board selection is not just about specs, but about which workflow best fits the project's needs.

Files

1 . Nicolas code — turn on a LED by a button.

2 . Micaela code — turn on a LED by a joystick.

week 4

Embedded Programming

Development Boards & Microcontrollers

What is a Development Board?

What is a Microcontroller?

Raspberry Pi Pico 2 W

Workflow Chain

Write code

Compile

Generate binary

Flash

Execute

Monitor

Toolchain

Arduino UNO R4 WiFi

Workflow Chain

Write code

Compile

Generate binary

Flash

Execute

Monitor

Toolchain

Arduino UNO R3

Workflow Chain

Write code

Compile

Generate binary

Flash

Execute

Monitor

Toolchain

Seeeduino XIAO nRF52840

Workflow Chain

Write code

Compile

Generate binary

Flash

Execute

Monitor

Toolchain

ESP32 (ESP32-WROOM)

Workflow Chain

Write code

Compile

Generate binary

Flash

Execute

Monitor

Toolchain

Arduino Nano

Development Board Comparison

Final Decision

Individual Reflections

Files