Writing an ESP32 program

To write our program, we need to follow these steps:

1. Modify the tft_demo.c file from the TFT library for ESP32. For this, we will use the circle_demo() function, as written here:

static void circle_demo()
{
  int x, y, r, n;
//In the upper part of the LCD display print the message “CIRCLE DEMO
  disp_header("CIRCLE DEMO");

1. Now draw some random circles on the LCD display using the TFT_drawCircle function. The circles will be randomly positioned on the screen and will have a random color with the help of the function random_color(). After that, the bottom header will be updated with the number of drawn circles (for example, 208 CIRCLES).

  uint32_t end_time = clock() + GDEMO_TIME;
  n = 0;
  while ((clock() < end_time) && (Wait(0))) {
    x = rand_interval(8, dispWin.x2-8);
    y = rand_interval(8, dispWin.y2-8);
    if (x < y) r = rand_interval(2, x/2);
    else r = rand_interval(2, y/2);
    TFT_drawCircle(x,y,r,random_color());
    n++;
  }
  sprintf(tmp_buff, "%d CIRCLES", n);
  update_header(NULL, tmp_buff);
  Wait(-GDEMO_INFO_TIME);

1. Now is the time to not only draw some circles but also fill to them with colors using the function TFT_fillCircle(). In the end, using the same values for x, y and r but different random_color() values, the circles will have a different filling and a different edge color.  

  update_header("FILLED CIRCLE", "");
  TFT_fillWindow(TFT_BLACK);
  end_time = clock() + GDEMO_TIME;
  n = 0;
  while ((clock() < end_time) && (Wait(0))) {
    x = rand_interval(8, dispWin.x2-8);
    y = rand_interval(8, dispWin.y2-8);
    if (x < y) r = rand_interval(2, x/2);
    else r = rand_interval(2, y/2);
    TFT_fillCircle(x,y,r,random_color());
    TFT_drawCircle(x,y,r,random_color());
    n++;
  }
  sprintf(tmp_buff, "%d CIRCLES", n);
  update_header(NULL, tmp_buff);
  Wait(-GDEMO_INFO_TIME);
}

1. Next, modify the tft_demo() function that calls the circle_demo() function:

void tft_demo() {

  ...

  // demo
  disp_header("Welcome to ESP32");
  circle_demo();


  while (1) {
    // do nothing
  }
}

1. Since we will use some components that are located on <project>/components, we should tell the compiler to include these components. We will add the component.mk file with our components included, as follows:

COMPONENT_SRCDIRS := . 
COMPONENT_ADD_INCLUDEDIRS := .

1. For the Makefile file, we can write these scripts as follows:

PROJECT_NAME := lcddemo

EXTRA_CFLAGS += --save-temps

include $(IDF_PATH)/make/project.mk

1. Save all files before configuring our project to compile and flash our program into the ESP32 board.

Now that we've created the program, let's configure our board.