PlatformIO Hello World for NodeMCU (ESP8266)

First steps

Driver installation

In the ./assets/ folder you will find a signed driver package you will need to install in order to be able to upload firmware to your board. Or download the file directly from here. Make sure to restart your computer after the driver install.

Software installation

PlatformIO is a game changer in micro-controller development, it's a first trully open-source multi-platform, multi-framework product with support for multiple IDEs. Let's install it!
Update/upgrade your brew : brew update && brew upgrade
Install pio brew install platformio

PlatformIO has a great package for Atom if you want to use a free IDE. You can download it here: https://atom.io/ The run: Atom > Preferences > Install and install these three packages:

• platformio-ide
• platformio-ide-terminal
• platformio-ide-debugger

But you can use any editor you please and build and upload to yur board from CLI.

Hello world time.... :)

First project

In the microcontroller you don't usually have screen to print to so the equivalent of a classic hello-world program would be to toggle a pin.. we can do better! The boards have a built-in LED on pin 2, let's make it flash.

Create your prohect folder mkdir helloesp && cd $_ Initialize the directory for your board: pio init -b nodemcuv2
And create a file .src/main.cpp with the following content:

#include <arduino.h>      // All sorts of goodies here...

const uint8_t LED = 2;    // LED is on pin 2

void setup(){             // This is run once and only once at the boot
  pinMode(LED, OUTPUT);   // We intend to write to this pin
  Serial.begin(115200);   // Initialize serial port
}

void loop(){              // All your programs will have an execution loop
  digitalWrite(LED, LOW); // This might look counter-intuitive but the LED ..
  Serial.println("ON");   // .. anode is connected to 3.3V and the cathode is..
  delay(1000);            // .. connected to PIN 2. When we then pull the pin ..
  digitalWrite(LED, HIGH);// .. low (0V), we create a voltage differential and ..
  Serial.println("OFF");  // .. the current flows. When we pull it high (3.3V) ..
  delay(1000);            // .. both LED pins are at 3.3V hence no current flow.
}

Check if it compiles with pio run or compile and upload with pio run --target upload. You should now see the blue LED flash on and off every 1 second.

To see the serial data sent from the board run screen /dev/$(ls /dev | grep "tty.*usb.*serial") 115200. When you had enough kill screen with Ctrl-ak, y.

Speed up upload times

Open platformio.ini file and add one line specifying the uplaod speed:

[env:nodemcuv2]
platform = espressif8266
board = nodemcuv2
framework = arduino
upload_speed = 921600