Initial commit: Simple Sensor firmware for Heltec T114 with BME280

- MeshCore-based Simple Sensor firmware
- Heltec T114 without display
- BME280 sensor support (temp/humidity/pressure)
- Radio: 868.856018 MHz, SF7, BW62.5 kHz, CR4/7
- 2-byte path hash
- PlatformIO project

variants/nano_g2_ultra/nano-g2.cpp

@@ -0,0 +1,42 @@
+#include <Arduino.h>
+#include "nano-g2.h"
+
+#ifdef NANO_G2_ULTRA
+
+#include <Wire.h>
+
+void NanoG2Ultra::begin()
+{
+  NRF52Board::begin();
+
+  // set user button
+  pinMode(PIN_BUTTON1, INPUT);
+
+  // the external notification circuit is shared for both buzzer and led
+  pinMode(EXT_NOTIFY_OUT, OUTPUT);
+  digitalWrite(EXT_NOTIFY_OUT, LOW);
+
+  pinMode(GPS_EN, OUTPUT); // Initialize GPS power pin
+  
+  Wire.begin();
+  pinMode(SX126X_POWER_EN, OUTPUT);
+  digitalWrite(SX126X_POWER_EN, HIGH);
+
+  delay(10);
+}
+
+uint16_t NanoG2Ultra::getBattMilliVolts()
+{
+  int adcvalue = 0;
+
+  analogReference(AR_INTERNAL_3_0);
+  analogReadResolution(12);
+  delay(10);
+
+  // ADC range is 0..3000mV and resolution is 12-bit (0..4095)
+  adcvalue = analogRead(PIN_VBAT_READ);
+  // Convert the raw value to compensated mv, taking the resistor-
+  // divider into account (providing the actual LIPO voltage)
+  return (uint16_t)((float)adcvalue * REAL_VBAT_MV_PER_LSB);
+}
+#endif