Added support for LilyGo T-Echo

src/helpers/nrf52/TechoBoard.h

@@ -0,0 +1,53 @@
+#pragma once
+
+#include <MeshCore.h>
+#include <Arduino.h>
+
+// LoRa radio module pins for LilyGo T-Echo
+#define  P_LORA_DIO_1     20
+#define  P_LORA_NSS       24
+#define  P_LORA_RESET     25
+#define  P_LORA_BUSY      17
+#define  P_LORA_SCLK      19
+#define  P_LORA_MISO      23
+#define  P_LORA_MOSI      22
+#define  SX126X_POWER_EN  37
+
+#define SX126X_DIO2_AS_RF_SWITCH  true
+#define SX126X_DIO3_TCXO_VOLTAGE   1.8
+
+// built-ins
+#define  PIN_VBAT_READ    4
+#define  ADC_MULTIPLIER   (2.0)
+
+class TechoBoard : public mesh::MainBoard {
+protected:
+  uint8_t startup_reason;
+
+public:
+  void begin();
+  uint8_t getStartupReason() const override { return startup_reason; }
+
+  #define BATTERY_SAMPLES 8
+
+  uint16_t getBattMilliVolts() override {
+    analogReadResolution(12);
+    uint32_t raw = 0;
+    for (int i = 0; i < BATTERY_SAMPLES; i++) {
+      raw += analogRead(PIN_VBAT_READ);
+    }
+    raw = raw / BATTERY_SAMPLES;
+
+    return (ADC_MULTIPLIER * raw) / 4096;
+  }
+
+  const char* getManufacturerName() const override {
+    return "LilyGo T-Echo";
+  }
+
+  void reboot() override {
+    NVIC_SystemReset();
+  }
+
+  bool startOTAUpdate() override;
+};