Blink for ESP8266 ESP-12E NodeMCU 1.0 Board, Arduino IDE: Hello world and function tests.

esp12e-blink.ino

// See the comment for flashing instruction.
#include <ESP8266WiFi.h>

#define ONBOARD_LED 16
#define ESP8266_LED 2

// ADC_MODE(ADC_VCC); will result in compile error. use this instead.
int __get_adc_mode(void) { return (int) (ADC_VCC); }

void setup() 
{
  pinMode(ONBOARD_LED, OUTPUT);
  pinMode(ESP8266_LED, OUTPUT);
  Serial.begin(115200);

  // Print Wi-Fi Information
  WiFi.printDiag(Serial);

  // Print VCC voltage
  Serial.print("Current VCC: ");
  Serial.println(ESP.getVcc());
}

void loop() 
{
  digitalWrite(ONBOARD_LED, HIGH);
  digitalWrite(ESP8266_LED, HIGH);
  Serial.println("LED on");
  delay(500);
  digitalWrite(ONBOARD_LED, LOW);
  digitalWrite(ESP8266_LED, LOW);
  Serial.println("LED off");
  delay(500);
}

Tested on Arduino IDE 1.6.7 or later.

Install Driver

USB to UART driver: http://cn.silabs.com/products/mcu/Pages/USBtoUARTBridgeVCPDrivers.aspx

Config

File - Preferences - Additional Boards Managers URLs: http://arduino.esp8266.com/stable/package_esp8266com_index.json
Tools -> Board -> Boards Manager -> search ESP8266 and install
Tools - Board: NodeMCU 1.0 (ESP-12E Module)
Tools - CPU Freq: 80MHz
Tools - Flash size: 4M (3M SPIFFS)
Tools - Upload speed: 921600 (115200 is also OK)
Tools - Port: select the port it is connected to.

Flashing

Now try to upload this code.

In most cases, it can be flashed directly. However, if you see the following error:

error: espcomm_open failed
error: espcomm_upload_mem failed

Try press and hold FLASH, press RESET, release RESET, release FLASH, then click Upload from Arduino IDE.

Result

2 LEDs (on both ESP module and the extension board) should flash 2 times per second.

Check Tools -> Serial Monitor (Set baudrate to the same value as in line 14 of the code), you should see Wi-Fi status, current voltage and LED switch status.