Added Heltec Lora32

Author: hallard

README.md

@@ -402,7 +402,7 @@ This board uses the following pin mapping:
      .nss = 17,
      .rxtx = LMIC_UNUSED_PIN,
      .rst = 18,
-     .dio = {23, 23, 23}, //workaround to use 1 pin for all 3 radio dio pins
+     .dio = {23, LMIC_UNUSED_PIN, LMIC_UNUSED_PIN}, 
  };
  ```
  You will also need Arduino ESP32 support from
@@ -412,6 +412,26 @@ This board uses the following pin mapping:
  mode. After programming reset the board without P3 shorted to ground to start
  in normal mode.
 
+ ### Heltec Lora32 (ESP32)
+ When using Heltec Lora32 you will need the following pin mapping:
+ 
+ ```
+ const lmic_pinmap lmic_pins = {
+     .mosi = 27,
+     .miso = 19,
+     .sck = 5,
+     .nss = 18,
+     .rxtx = LMIC_UNUSED_PIN,
+     .rst = 14,
+     .dio = {26, 33, 32}, 
+ };
+
+ ```
+ On Board OLED is I2C with SCL=GPIO15, SDA=GPIO4 and OLED_RST=GPIO16.
+ You will also need Arduino ESP32 support from
+ https://github.com/espressif/arduino-esp32. Use the "ESP32 Dev Module" as target
+ device.
+
 
 Examples
 --------