Week 6 - Embedded programming

This week’s assignment included the following tasks:

• Browse through the datasheet for your microcontroller
• Compare the performance and development workflows for other architectures

We compared: * ATtiny85: https://www.digikey.com/en/products/detail/microchip-technology/attiny84-20ssu/1886247 * ATSAMD11C: https://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-42363-SAM-D11_Datasheet.pdf * ESP32: https://www.espressif.com/sites/default/files/documentation/esp32_datasheet_en.pdf * RP2040: https://datasheets.raspberrypi.com/rp2040/rp2040-datasheet.pdf

TABLE COMPARISION

SPECS	ATtiny85	ATSAMD11C	ESP32	RP2040
PROCESSOR	AVR-RISC, up to 20 MHz	ARM Cortex-M0+ CPU, up to 48MHz	CPU: 32-bit Xtensa LX6 dual-core (or single-core) microprocessor, operating at 160 or 240 MHz and yielding up to 600 DMIPS and the Ultra Low Power (ULP) co-processor	Dual Cortex M0+ processor cores, up to 133 MHz
PINS	14	14	9 pins for contact sensors and 16 PWM.	26
I/O PINS	12	12	25 digital inputs/outputs	15 (11 Digital, 4 Analog)
OPERATING VOLTAGE	2.7 – 5.5V	1.62V – 3.63V	2.2 to 3.6V	3.3V - 5V
FLASH	8KB	16KB	4MB	2MB
SRAM	0,5KB	4KB	400KB SRAM	264KB
TIME COUNTER (TC)	8-bit	2	64-bit generic timers based on 16-bit pre-scalers and 64-bit up / down counters	21 bit
TIME COUNTER FOR CONTROL	2	1	2	1
USB INTERFACE	0	1	1	1 (Type C)

• ATtiny85: Best for simple, low-power applications like LED drivers or sensor interfaces, due to its simplicity and low resource requirements.
• ATSAMD11C: Suitable for intermediate projects needing higher processing power and USB connectivity, with a balance between capability and ease of use.
• ESP32: Ideal for advanced IoT projects with its high processing power, extensive memory, and built-in Wi-Fi/Bluetooth, offering wide development platform support.
• RP2040: Versatile for projects requiring custom I/O operations and supports a wide range of programming environments, lacking built-in wireless connectivity.

PERFORMANCE ANNALYSIS

ATtiny85

• Pinout
• low-power microcontroller from the AVR family
• designed for simple applications with modest computational needs
• it has 8 KB of flash memory, 512 bytes of EEPROM, and 512 bytes of SRAM
• operates at up to 20 MHz
• can be programmed with Arduino or USBtinyISP
• development environment: generally AVR-GCC and AVR Libc
• suitable for basic applications like simple sensor interfaces, LED drivers, etc.
• Datasheet

ATSAMD11C

• Pinout

• 32-bit ARM Cortex-M0+ microcontroller

• higher performance than the ATtiny85
• designed for slightly more complex tasks
• can operate up to 48 MHz
• typically comes with 16 KB of flash memory and 4 KB of SRAM
• usually programmed using the Atmel Studio or Arduino IDE
• it supports sophisticated development tools and debugging options
• appropriate for intermediate projects that require higher processing capabilities and USB functionality

ESP32

• Pinout

• high-performance microcontroller with integrated Wi-Fi and Bluetooth

• dual-core processor that can run up to 240 MHz
• up to 520 KB of SRAM and higher flash memory options
• ideal for IoT applications
• supports various development platforms, including the Arduino IDE, MicroPython, Espressif IDF, etc
• it offers features like networking, OTA updates, and deep sleep modes
• due to these features, the development environment is more complex

RP2040

• Pinout
• dual-core ARM Cortex-M0+ microcontroller
• operates at up to 133 MHz
• 264 KB of SRAM and supports external flash memory
• known for its programmable I/O feature
• can be programmed using C/C++ SDK, MicroPython, or CircuitPython
• popular for its ease of use and set of libraries available

DEVELOPMENT WORKFLOW ANNALYSIS - SETTING UP A “HELLO WORLD”/BLINKING PROGRAM

We tested the workflow of RP2040 (included in the Quentorres boards we made Electronics Production week) and the ESP32 (included in the Barduino board from FABLAB BCN):

Testing RP2040 with Arduino IDE

1. Download and install the Arduino IDE from the Arduino website
2. Add RP2040 Boards to Arduino IDE:
   • Open the Arduino IDE
   • Go to File > Preferences
   • In the “Additional Boards Manager URLs” field, add the URL for the Raspberry Pi Pico/RP2040 boards: https://github.com/earlephilhower/arduino-pico/releases/download/global/package_rp2040_index.json
   • Go to Tools > Board > Boards Manager, search for “RP2040”, and install the “Raspberry Pi Pico/RP2040” by Earle Philhower
3. Connect the board with the RP2040 to the computer with a micro-USB cable
4. Select the board and port:
   • Tools > Board and select “Raspberry Pi Pico”
   • Tools > Port for the COM port the USB is connected to
5. Write and verify code
   • Go to File > Examples > 01.Basics > Blink
   • Opend the file

// the setup function runs once when you press reset or power the board
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
}

1. Looking for the pinout to change the file

• Changing pinMode and adding two other LED

1. Click “Upload” button
2. The LEDs should start blinking

Testing ESP32 with MicroPython, using Thonny

1. Download and install Thonny from Thonny’s website

2. Install MicroPython on ESP32:

   • Connect the ESP32 to the computer via a micro-USB cable
   • On Thonny, and go to Tools > Options
   • Under the “Interpreter” tab, select “MicroPython (ESP32)” from the dropdown.
   • Click “Install or update firmware” and follow the instructions to install MicroPython on your ESP32

3. Select the appropriate COM port for the ESP32

1. Write and verify the code

1. Click “run the current script” button
2. The LED should start blinking