ESP32 "Hello World" Example

This is a simple "Hello World" example for the ESP32, using the ESP-IDF C++ framework.

Setup

These steps only need to be performed once.

Install Prerequisites:
```
brew install cmake ninja dfu-util
```

Clone the ESP-IDF repository:

mkdir ~/esp
cd ~/esp
git clone --recursive https://github.com/espressif/esp-idf.git

Install ESP-IDF Tools:
```
cd ~/esp/esp-idf
./install.sh
```
Set up Environment Variables: To make the idf.py command available in every terminal session, add the following alias to your shell's profile script (e.g., ~/.zshrc or ~/.bash_profile):
```
echo "alias get_idf='. $HOME/esp/esp-idf/export.sh'" >> ~/.zshrc
```
Then, in any new terminal, you can type get_idf to set up the environment.

Creating a New Project

To create a new project, you can copy the hello_world example:

cp -r ~/esp/esp-idf/examples/get-started/hello_world ~/esp/my_new_project
cd ~/esp/my_new_project

Building and Flashing

Navigate to your project directory:
```
cd ~/esp/hello_world 
```
Set up the environment in your new terminal:
```
. ~/esp/esp-idf/export.sh
```
Or, if you've set up the alias:
```
get_idf
```
Set the target chip (only needs to be done once per project):
```
idf.py set-target esp32
```
Build the project:
```
idf.py build
```
Flash and monitor the project: Connect your ESP32 board and run:
```
idf.py -p /dev/cu.usbserial-10 flash monitor
```
(Replace /dev/cu.usbserial-10 with your device's serial port if it's different.)

To exit the monitor, press Ctrl+].

Program Walkthrough

The main logic is in main/hello_world_main.c.

It starts by printing "Hello world!".
Then, it retrieves and prints information about the ESP32 chip, including the number of cores, features (WiFi, BT, BLE), silicon revision, and flash size.
It prints the minimum free heap size.
Finally, it counts down from 10 and restarts the device.

Next Steps

Now that you have a working development environment, you can start exploring the other examples in the ~/esp/esp-idf/examples directory. These examples cover a wide range of functionalities, from GPIO and timers to Wi-Fi and Bluetooth.

You can also start writing your own applications by modifying the hello_world_main.c file or creating new source files in the main directory.