added variant rak3401

variants/rak3401/RAK3401Board.cpp

@@ -0,0 +1,37 @@
+#include <Arduino.h>
+#include <Wire.h>
+
+#include "RAK3401Board.h"
+
+void RAK3401Board::begin() {
+  NRF52BoardDCDC::begin();
+  pinMode(PIN_VBAT_READ, INPUT);
+#ifdef PIN_USER_BTN
+  pinMode(PIN_USER_BTN, INPUT_PULLUP);
+#endif
+
+#ifdef PIN_USER_BTN_ANA
+  pinMode(PIN_USER_BTN_ANA, INPUT_PULLUP);
+#endif
+
+#if defined(PIN_BOARD_SDA) && defined(PIN_BOARD_SCL)
+  Wire.setPins(PIN_BOARD_SDA, PIN_BOARD_SCL);
+#endif
+
+  Wire.begin();
+
+  // Enable 3.3V periphery power rail (GPS, IO Module, etc.)
+  pinMode(PIN_3V3_EN, OUTPUT);
+  digitalWrite(PIN_3V3_EN, HIGH);
+
+  pinMode(SX126X_POWER_EN, OUTPUT);
+  digitalWrite(SX126X_POWER_EN, HIGH);
+  delay(10);   // give sx1262 some time to power up
+
+#ifdef P_LORA_PA_EN
+  // Initialize RAK13302 1W LoRa transceiver module PA control pin
+  pinMode(P_LORA_PA_EN, OUTPUT);
+  digitalWrite(P_LORA_PA_EN, LOW);  // Start with PA disabled
+  delay(10);  // Allow PA module to initialize
+#endif
+}