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Lab Session 0: Initial steps

Estimated time: 1.5h (1 session)

1. Microcontrollers simulation

Launch an example

  • Access the Wokwi simulation environment via this link.

  • Select the ESP32 template.

    Warning

    Open the ESP32 template from Starter Templates, not from ESP-IDF Templates. The former is based on the Arduino IDE while the latter is based on the ESP-IDF environment that will not be used in the course.

  • Simulate the example sketch:

    void setup() {
// put your setup code here, to run once:
Serial.begin(115200);
Serial.println("Hello, ESP32!");
}

void loop() {
// put your main code here, to run repeatedly:
delay(10); // this speeds up the simulation
}

    Warning

    Here you are simulating the behavior of the system including the code, you are not compiling the code (i.e., we're not generating the machine-readable code that will be executed by a processor). But the code MUST be compliable (i.e., it will be verified to check that I would compile )

    Info

    • Note that the real-time factor at the top right corner should be as close as possible to 100%. This value is a simulation performance metric. The closer it gets to 100%, the better is the simulation. A value of 100% means the simulation is running in real-time. If the value drops, the times in the simulation are no longer reliable.
    • Note the instruction delay(10); // this speeds up the simulation. Try to comment this line and see what happens. What if you put delay(1); or delay(5);?

    Question

    • What is the purpose of the setup() function?
    • What is the purpose of the loop() function?
    • What does the delay() function do?
    • Why do we need to put the delay(10) inside the loop() function?

Add hardware components

  • First of all, check the diagram.json file . What information do you see there?

  • Connect an LED to GPIO 21 with a resistor, as shown in the diagram (rotate - R and flip - P components if necessary).

    Question

    • Check again the diagram.json. What happened? Can you change the color of the LED to green from this file?
    • What do you think you can do with the Library Manager?

2. Prepare the Arduino IDE

Follow the installation steps described in this guide.

  1. Install Arduino IDE: Download it from this link.

  2. Install the M5Stack board family:

    You need to copy/paste this text to download the board package

    https://static-cdn.m5stack.com/resource/arduino/package_m5stack_index.json

    Once the board package address is set, you can install it from the boards manager.

    Warning

    Remember to install the version 2.1.4. If you try to install version 3.X you won't be able to do exercises of the lab sessions. We'll talk about the versions 2.X and 3.X later and how to migrate our code from one to another. For now, just use the 2.X version.

    Danger

    Once you've done this, if you open the Arduino IDE later, a message will pop up letting you know that there are updates available for some libraries and asking whether you want to install the updates or not. Don't update the libraries

    Info

    This process may take a few minutes.

    Once installed, you can select M5Core2 from the board selection menu.

  3. Install the Arduino libraries for M5Core2:

    Warning

    When you press Install, you'll see the list of dependencies. You MUST install all the dependencies too.

    Info

    This is a long process that may take several minutes. Be patient...

    Tip

    In case the list of dependencies is that large that you cannot see the Install All button, you can press the tab key Tab twice to put the cursor over the button and then press Enter to install all the dependencies.

  4. Install the CP2104 driver (USB driver):

    Download it from this link if you're using Windows, from this link if you're using MacOS, or from this other link if you're using Linux.

    More info about USB driver installation here.

    Now, when you connect the M5Core2 devide to the PC with the USB cable, you can select the port in the Arduino IDE.

    Info

    • In windows, the port is called COMX, where X is a number that can vary from time to time, e.g., COM5.
    • In linux, the port is called "ttyUSBX" or "ttyACMX", where X is a number that can vary from time to time, e.g., ttyUSB2.

  5. Compile and upload the hello_world.ino example from M5Core2 library:

    You can press the Upload (in red) button to compile and load the program to the device. Note that the button on the left (Verify - in green) compiles the program but doesn't upload it to the device.

  6. OPTIONAL (do it ONLY if you have finished all the exercises of the lab session): You can open other examples if you want to see the potential of M5Core2. You can try this one:

Additional resources

Here you can find more documentation about some of the basic functions of M5Core2.

Pinout and Important Notes Below is the M5Core2 pinout. The pins marked in red are the ones we will use in the exercises.

Warning

  • Some pins on the M5Core2 are preconfigured, so pay attention when connecting external components.
  • The ESP32 inside the M5Core2 has 3 serial ports:
    • Serial1 is reserved for the display (do not use it).
    • Serial0 can be configured (pins G3 – RXD0 and G1 – TXD0), but it is reserved for USB connection to the PC.
    • Serial2 is free and can be configured (pins G13 – RXD2 and G14 – TXD2) as regular GPIO using pinMode().