initial support for lilygo t impulse plus

variants/lilygo_t_impulse_plus/TImpulsePlusBoard.cpp

@@ -0,0 +1,39 @@
+#include <Arduino.h>
+#include <Wire.h>
+
+#include "TImpulsePlusBoard.h"
+
+void TImpulsePlusBoard::begin() {
+  NRF52BoardDCDC::begin();
+
+  // turn on 3.3v
+  pinMode(RT9080_EN, OUTPUT);
+  digitalWrite(RT9080_EN, HIGH);
+  delay(100);
+
+  // init gps pins
+  pinMode(GPS_EN, OUTPUT);
+  digitalWrite(GPS_EN, HIGH); // gps off by default
+
+  // configure battery measurement
+  pinMode(BATTERY_ADC_DATA, INPUT);
+  pinMode(BATTERY_MEASUREMENT_CONTROL, OUTPUT);
+  digitalWrite(BATTERY_MEASUREMENT_CONTROL, LOW); // turn off battery voltage measurement
+
+  // set the analog reference to 3.0V (default = 3.6V)
+  analogReference(AR_INTERNAL_3_0);
+  
+  // set the resolution to 12-bit (0..4095)
+  analogReadResolution(12); // Can be 8, 10, 12 or 14
+
+  // configure user button
+  pinMode(TTP223_KEY, INPUT_PULLDOWN);
+
+  #if defined(PIN_WIRE_SDA) && defined(PIN_WIRE_SCL)
+    Wire.setPins(PIN_WIRE_SDA, PIN_WIRE_SCL);
+  #endif
+
+  Wire.begin();
+
+  delay(10); // give sx1262 some time to power up
+}