* BIG refactor: 'board' and 'radio' objects now defined in 'target.h/.cpp'

* mesh::RTCClock class moved to MeshCore.h

variants/rak4631/platformio.ini

@@ -4,6 +4,7 @@ platform = https://github.com/maxgerhardt/platform-nordicnrf52.git#rak
 board = wiscore_rak4631
 board_check = true
 build_flags = ${nrf52840_base.build_flags}
+  -I variants/rak4631
   -D RAK_4631
   -D PIN_USER_BTN=9
   -D RADIO_CLASS=CustomSX1262
@@ -13,6 +14,7 @@ build_flags = ${nrf52840_base.build_flags}
   -D SX126X_RX_BOOSTED_GAIN=1
 build_src_filter = ${nrf52840_base.build_src_filter}
   +<helpers/nrf52/*.cpp>
+  +<../variants/rak4631>
 lib_deps =
   ${nrf52840_base.lib_deps}
   adafruit/Adafruit SSD1306 @ ^2.5.13

variants/rak4631/target.cpp

@@ -0,0 +1,41 @@
+#include <Arduino.h>
+#include "target.h"
+
+RAK4631Board board;
+
+RADIO_CLASS radio = new Module(P_LORA_NSS, P_LORA_DIO_1, P_LORA_RESET, P_LORA_BUSY, SPI);
+
+#ifndef LORA_CR
+  #define LORA_CR      5
+#endif
+
+bool radio_init() {
+#ifdef SX126X_DIO3_TCXO_VOLTAGE
+  float tcxo = SX126X_DIO3_TCXO_VOLTAGE;
+#else
+  float tcxo = 1.6f;
+#endif
+
+  SPI.setPins(P_LORA_MISO, P_LORA_SCLK, P_LORA_MOSI);
+  SPI.begin();
+  int status = radio.begin(LORA_FREQ, LORA_BW, LORA_SF, LORA_CR, RADIOLIB_SX126X_SYNC_WORD_PRIVATE, LORA_TX_POWER, 8, tcxo);
+  if (status != RADIOLIB_ERR_NONE) {
+    Serial.print("ERROR: radio init failed: ");
+    Serial.println(status);
+    return false;  // fail
+  }
+  
+  radio.setCRC(1);
+  
+#ifdef SX126X_CURRENT_LIMIT
+  radio.setCurrentLimit(SX126X_CURRENT_LIMIT);
+#endif
+#ifdef SX126X_DIO2_AS_RF_SWITCH
+  radio.setDio2AsRfSwitch(SX126X_DIO2_AS_RF_SWITCH);
+#endif
+#ifdef SX126X_RX_BOOSTED_GAIN
+  radio.setRxBoostedGainMode(SX126X_RX_BOOSTED_GAIN);
+#endif
+
+  return true;  // success
+}

variants/rak4631/target.h

@@ -0,0 +1,9 @@
+#pragma once
+
+#include <helpers/nrf52/RAK4631Board.h>
+#include <helpers/CustomSX1262Wrapper.h>
+
+extern RAK4631Board board;
+extern RADIO_CLASS radio;
+
+bool radio_init();