Week 3 : Embedded Programming

Programs

• Arduino
• Wokwi (Simulator) - https://wokwi.com/

Individual Project

• Browse through the data sheet for your microcontroller
• Write a program for a microcontroller, and simulate its operation, to interact (with local input &/or output devices)

This week, I used Wokwi to simulate an LED fading effect on an ESP32 board. The code and demo are below:

int led = 18;         // the PWM pin the LED is attached to
int brightness = 0;   // how bright the LED is
int fadeAmount = 5;   // how many points to fade the LED by

// the setup routine runs once when you press reset:
void setup() {
  pinMode(led, OUTPUT); // declare pin 9 to be an output
}

// the loop routine runs over and over again forever:
void loop() {
  analogWrite(led, brightness); // set the brightness of pin 9

  brightness = brightness + fadeAmount; // change the brightness

  // reverse the direction of fading at the ends of the fade
  if (brightness <= 0 || brightness >= 255) {
    fadeAmount = -fadeAmount;
  }
  delay(10); // wait for 30 milliseconds to see the dimming effect
}
            

Group Assignment

Demonstrate and compare the toolchains and development workflows for alternative embedded architectures.

We learned about different boards and protocols used in microcontroller communication:

• JTAG / SWD: JTAG requires 4 signal lines, while SWD requires only 2.
• AVR 8 / ARM: ATtiny 1,2 series and AVR Dx are AVR 8-bit microcontrollers, requiring multiple cycles to process 16-bit instructions, while ARM-based boards like SAMD, RP2040, and ESP32 are more powerful.
• SAMD / RP2040 / ESP32: ARM-based boards, with SAMD functioning as a native USB device, RP2040 lacking built-in flash memory but featuring user-friendly documentation, and ESP32 offering WiFi and Bluetooth, suitable for more complex projects.

SWD is an ARM-specific protocol designed for micro debugging.