Week_4 Assignments

This week I will explore more about microcontrollers architecture, capabilities and more about programming them. I have experience using Arduino uno , Arduino nano, Arduino mega, Esp8266 mini, Esp8266 Node Mcu and Esp 32 dev board programming them using rduino IDE.
this week I want to program them using micropython not arduino c and also use platformIO IDE extension in VScode.

This week I have a group assignment and individual assignment:

• Group assignment
• We need to explore as many embedded systems hardware capabilities, software toolchain to program them and compare them according to the mentioned points
• Individual assignment
• Walk through a datasheet of a microcontroller.
• Write a program for a microcontroller and simulate its operation. Design it to interact meaning it should have input and output devices and communication.

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Group assignment

We discussed the difference between Von Neumann and Harvard MCUs structures and the main diifference is that the exiestance of a shared memory in between the program data and instruction data in the Von Neumann archeticture on the other hand the harvard archeticture has a seperate memory for each data.

We also walked through the datasheet of two different MCUs: ATmega328p and ESP32. we found that the ESP32 has great capabilities when compared with ATmega328p as it has more Flash memory, more EEPROM memory, has more communication protocols and has a built-in wifi and bluetooth prepherals.

We talked about different toolchains to deal with each MCUs like we can use AVRdude to configure the atmega328p and to upload the code using its hex file.
Also for atmega328p we can use AVRstudio to convert the code into hex file "machine language". We found that the easiest way to program an ATmega328p MCU is to use Arduino IDE as it has all the toolchains integrated in it.

As for the ESP 32 the easiest way is to use Arduino IDE but if you want to do deeper and use something like AVRdude you can use ESP IDF.

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Individual assignment

Simulations

I have experience using Tinkercad as my go to Arduino programming simulator and playground so I tried Wokwi as the simulation for using a board like Xiao Esp32 C3.

I used Xiao Esp 32 C3 as the MCU. I used a potentiometer as an input and the output is an OLED display using I2C protocol to communicate with the Xiao board.

"Circuit Wiring"

We need to know the pinout of the Xiao board and how it is like:

The wiring is a piece of cake ^^.

• First I connected the potentiometer to the Xiao board. The potentiometer has 3 pins "GND, Signal and VCC".

I connected the GND to the GND of the Xiao board and the same with the VCC pin to the 5V pin in the Xiao board and finally the signal pin connected it to the D1 pin.
• I connected the OLED display to the Xioa. The OLED display has 4 pins "VCC, GND, SCL and SDA".
  The connection is straight forward the VCC with the 5V pin in the Xiao, the GND with the GND, the SCL pin is conned pin D5 as shown int the pinout diagram and the SDA pin is connected to D4 pin.

And just like that we finished wiring the components let's move to the programming where I used this tutorial to learn how to program the I2C OLED display with an ESP 32 board

"Coding ^^"

#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64 

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

int potpin = D1;
int potvalue;

void setup () {
  Serial.begin(115200);
  
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  
  delay(2000);
  display.clearDisplay();
}

void loop () {
  potvalue = analogRead(potpin);
  Serial.println(potvalue);

  if (potvalue >= 0 && potvalue < 2040) {
    display.clearDisplay();
    display.fillRoundRect(10, 40, 30, 20, 2, WHITE);
    display.fillRoundRect(80, 40, 30, 20, 2, WHITE);
    display.display();
  } else {
    display.clearDisplay();
    display.fillRoundRect(10, 10, 30, 50, 2, WHITE);
    display.fillRoundRect(80, 10, 30, 50, 2, WHITE);
    display.display();
  }
}

• Started the code by including the libraries used buy the OLED I2C display

  #include <SPI.h>
  #include <Wire.h>
  #include <Adafruit_GFX.h>
  #include <Adafruit_SSD1306.h>
  

• Defined the dimensions of the OLED display and made the display object which can be named any name.

    #define SCREEN_WIDTH 128
    #define SCREEN_HEIGHT 64 
    
    Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);
    

• Defined variables to assign the potentiometer signal pin connected to the Xiao a name and defined a variable to hold the value which returns when reading the potentiometer readings.

    int potpin = D1;
    int potvalue;
    

• Inside the void setup function I started the serail communication to display the readings later on the serial monitor and initiate the I2C connection with the OLED and started the OLED display.

    void setup () 
    {
      Serial.begin(115200);
      
      if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
        Serial.println(F("SSD1306 allocation failed"));
        for(;;);
      }
      
      delay(2000);
      display.clearDisplay();
    }
    

• Inside the void loop function I started by getting the readings of the potentiometer using the analorRead() function which returns a value between 0 and 4095 as the ADC in the Xiao is 12 bits.
• Then printing the readings to the Serial monitor. and run an If statement to control the display according to the readings.
• Using the fillRoundRect() method to draw a rounded rectangle passing the parameters of (x, y, width, height,radius,colour)
• Using clearDisplay() to clear the OLED display ^^ of course and display() to display on the OLED ^^

    void loop () {
      potvalue = analogRead(potpin);
      Serial.println(potvalue);
    
      if (potvalue >= 0 && potvalue < 2040) {
        display.clearDisplay();
        display.fillRoundRect(10, 40, 30, 20, 2, WHITE);
        display.fillRoundRect(80, 40, 30, 20, 2, WHITE);
        display.display();
      } else {
        display.clearDisplay();
        display.fillRoundRect(10, 10, 30, 50, 2, WHITE);
        display.fillRoundRect(80, 10, 30, 50, 2, WHITE);
        display.display();
      }
    }
    

you can see the magic happens ^^:

You can download my files from here:

• Xiao Simulation "Make me Sleep and Wake me up "