xiao-nrf52 : initial support for meshcore

initial config for xiao_nrf52

repeater role for xiao-nrf52

xiao-nrf52 correction on bat voltage

xiao-nrf52 this file should not be here ...

src/helpers/nrf52/XiaoNrf52Board.h

@@ -0,0 +1,75 @@
+#pragma once
+
+#include <MeshCore.h>
+#include <Arduino.h>
+
+// LoRa radio module pins for Seeed Xiao-nrf52
+#ifdef SX1262_XIAO_S3_VARIANT
+  #define  P_LORA_DIO_1       D0
+  #define  P_LORA_BUSY        D1
+  #define  P_LORA_RESET       D2
+  #define  P_LORA_NSS         D3
+  #define  LORA_TX_BOOST_PIN  D4
+#else
+  #define  P_LORA_DIO_1       D1
+  #define  P_LORA_BUSY        D3
+  #define  P_LORA_RESET       D2
+  #define  P_LORA_NSS         D4
+  #define  LORA_TX_BOOST_PIN  D5
+#endif
+#define  P_LORA_SCLK        PIN_SPI_SCK
+#define  P_LORA_MISO        PIN_SPI_MISO
+#define  P_LORA_MOSI        PIN_SPI_MOSI
+//#define  SX126X_POWER_EN  37
+
+#define SX126X_DIO2_AS_RF_SWITCH  true
+#define SX126X_DIO3_TCXO_VOLTAGE   1.8
+
+
+class XiaoNrf52Board : public mesh::MainBoard {
+protected:
+  uint8_t startup_reason;
+
+public:
+  void begin();
+  uint8_t getStartupReason() const override { return startup_reason; }
+
+#if defined(P_LORA_TX_LED)
+  void onBeforeTransmit() override {
+    digitalWrite(P_LORA_TX_LED, LOW);   // turn TX LED on
+  }
+  void onAfterTransmit() override {
+    digitalWrite(P_LORA_TX_LED, HIGH);   // turn TX LED off
+  }
+#endif
+
+  uint16_t getBattMilliVolts() override {
+    // Please read befor going further ;)
+    // https://wiki.seeedstudio.com/XIAO_BLE#q3-what-are-the-considerations-when-using-xiao-nrf52840-sense-for-battery-charging
+
+    pinMode(BAT_NOT_CHARGING, INPUT);
+    if (digitalRead(BAT_NOT_CHARGING) == HIGH) {
+      int adcvalue = 0;
+      analogReadResolution(12);
+      analogReference(AR_INTERNAL_3_0);  
+      digitalWrite(VBAT_ENABLE, LOW);
+      delay(10);
+      adcvalue = analogRead(PIN_VBAT);
+      digitalWrite(VBAT_ENABLE, HIGH);
+      return (adcvalue * ADC_MULTIPLIER * AREF_VOLTAGE) / 4.096;
+    } else {
+      digitalWrite(VBAT_ENABLE, HIGH); // ensures high !
+      return 4200; // charging value
+    }
+  }
+
+  const char* getManufacturerName() const override {
+    return "Seeed Xiao-nrf52";
+  }
+
+  void reboot() override {
+    NVIC_SystemReset();
+  }
+
+  bool startOTAUpdate(const char* id, char reply[]) override;
+};