Embedded Programming Week¶
For this week’s group assignment, we explored the different microcontrollers available in our lab. We decided to focus on three specific boards: the Arduino UNO, XIAO ESP32C3, and ATtiny 44.
Our goal wasn’t just to test them, but to actually understand their specifications like their pin configurations and how to program them, and to see how they differ from each other. This helped us get a better understanding of what each board can do.
We used the Arduino IDE to write our code. It let us compile, debug, and upload the program to the board.
Arduino UNO¶
Board Specifications:
The Arduino UNO R3 is the most popular board in the Arduino family and is perfect for beginners like us. It runs on the ATmega328P chip and is designed to be really easy to use for learning electronics and coding.
Board¶
| Name | SKU |
|---|---|
| Arduino UNO R3 | A000066 |
Microcontroller¶
| Component | Specification |
|---|---|
| Microcontroller | ATmega328P |
| USB Connector | USB-B |
Pins¶
| Feature | Specification |
|---|---|
| Built-in LED Pin | 13 |
| Digital I/O Pins | 14 |
| Analog Input Pins | 6 |
| PWM Pins | 6 |
Communication¶
| Protocol | Supported |
|---|---|
| UART | Yes |
| I2C | Yes |
| SPI | Yes |
Power¶
| Feature | Specification |
|---|---|
| I/O Voltage | 5V |
| Input Voltage (nominal) | 7-12V |
| DC Current per I/O Pin | 20 mA |
| Power Supply Connector | Barrel Plug |
Clock Speed¶
| Processor | Speed |
|---|---|
| Main Processor | ATmega328P 16 MHz |
| USB-Serial Processor | ATmega16U2 16 MHz |
Memory¶
| Component | Specification |
|---|---|
| ATmega328P | 2KB SRAM, 32KB FLASH, 1KB EEPROM |
Dimensions¶
| Feature | Specification |
|---|---|
| Weight | 25 g |
| Width | 53.4 mm |
| Length | 68.6 mm |
The above information was taken from the datasheet of the board. Here is the link to the datasheet
For this week’s assignment, we used the classic Blink example that comes with the Arduino IDE.
To open it, we went to: File > Examples > Basics > Blink
Here is the code we used:
void setup() {
// initialize digital pin LED_BUILTIN as an output.
pinMode(LED_BUILTIN, OUTPUT);
}
// the loop function runs over and over again forever
void loop() {
digitalWrite(LED_BUILTIN, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(LED_BUILTIN, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second
}
For the Arduino UNO R3 we first connected the board to the computer and then uploaded the code. Don’t forget to add the board and the port!
Yay! Our LED is blinking!
XIAO ESP32C3¶
Board Specifications:
The Seeed Studio XIAO ESP32C3 is a tiny microcontroller board powered by the Espressif ESP32-C3 RISC-V chip, and it’s made for IoT and wearable projects. It has 2.4GHz Wi-Fi and Bluetooth 5.0 (LE) packed into a really small size. It also has a built-in battery charging chip and uses very little power, which makes it great for battery-powered projects where space is tight.
Board¶
| Name | SKU |
|---|---|
| Seeed Studio XIAO ESP32C3 | 113991054 |
Microcontroller¶
| Component | Specification |
|---|---|
| Microcontroller | ESP32-C3 SoC (32-bit RISC-V) |
| USB Connector | USB Type-C |
Pins¶
| Feature | Specification |
|---|---|
| Built-in LED Pin | N/A (Charge LED only) |
| Digital I/O Pins | 11 |
| Analog Input Pins | 4 |
| PWM Pins | 11 |
Communication¶
| Protocol | Supported |
|---|---|
| UART | Yes |
| I2C | Yes |
| SPI | Yes |
Power¶
| Feature | Specification |
|---|---|
| I/O Voltage | 3.3V |
| Input Voltage (nominal) | 5V (USB) / 3.7V (Battery) |
| DC Current per I/O Pin | 40 mA (Max) |
| Power Supply Connector | USB Type-C / Battery Pads |
Clock Speed¶
| Processor | Speed |
|---|---|
| Main Processor | 160 MHz |
| USB-Serial Processor | Native Internal USB Serial/JTAG |
Memory¶
| Component | Specification |
|---|---|
| ESP32-C3 | 400KB SRAM, 4MB Flash |
Dimensions¶
| Feature | Specification |
|---|---|
| Weight | ~3 g |
| Width | 17.5 mm |
| Length | 21 mm |
The above information was taken from the datasheet of the board. Here is the link to the datasheet
We used the same code, but since the XIAO ESP32C3 doesn’t have a built-in LED, we used the GPIO10 pin to turn an external LED on and off. Don’t forget to add the board and the port!
Yay! Our LED is blinking!
ATtiny 44¶
Board Specifications:
The ATtiny44 is a tiny, low-power microcontroller that’s great for small and compact projects. It has 12 I/O pins and 4KB of memory.
Board¶
| Name | Value |
|---|---|
| Name | ATtiny44A |
| Manufacturer | Atmel (Microchip) |
Microcontroller¶
| Component | Specification |
|---|---|
| Microcontroller | ATtiny44A |
| USB Connector | None |
Pins¶
| Feature | Specification |
|---|---|
| Built-in LED Pin | None |
| Digital I/O Pins | 12 |
| Analog Input Pins | 8 |
| PWM Pins | 4 |
Communication¶
| Protocol | Supported |
|---|---|
| UART | No |
| I2C | Yes (USI) |
| SPI | Yes (USI) |
Power¶
| Feature | Specification |
|---|---|
| I/O Voltage | 1.8V – 5.5V |
| Input Voltage (nominal) | 1.8V – 5.5V |
| DC Current per I/O Pin | 40 mA |
| Power Supply Connector | VCC Pin |
Clock Speed¶
| Processor | Speed |
|---|---|
| Main Processor | Up to 20 MHz |
| Internal RC Oscillator | 8 MHz |
Memory¶
| Component | Specification |
|---|---|
| ATtiny44A | 256B SRAM, 4KB Flash, 256B EEPROM |
Dimensions & Package¶
| Feature | Specification |
|---|---|
| Available Packages | 14-pin PDIP, 14-pin SOIC, QFN/MLF, VQFN, UFBGA |
| Operating Temperature | –40°C to +85°C |
For the ATtiny 44, we used an ATtiny 44 circuit board that students in the lab had made before. To program it we used Arduino as ISP as shown below.
ISP is basically a way to program a microcontroller while it’s already on a circuit board, so you don’t have to take the chip out and put it in a separate programmer.
After that, use the default Blink code but change the pin number to the one your LED is connected to. Our pin is PA2.
Don’t forget to add the board and the port!
Reflection¶
This week was a really great learning experience for us. We compared the Arduino UNO, XIAO ESP32C3, and ATtiny44 by looking at their datasheets and programming all three of them to blink an LED. We learned how different they are in terms of specs and how you program them, especially using ISP for the ATtiny. Now we have a much better idea of how to pick the right microcontroller depending on what kind of project we’re working on.