Merge pull request #1413 from entr0p1/powermgt-nrf52840-v2

nRF52840 Power Management v2 Phase 1 - LPCOMP Wake and startup lockout

src/MeshCore.h

@@ -56,6 +56,14 @@ public:
   virtual void setGpio(uint32_t values) {}
   virtual uint8_t getStartupReason() const = 0;
   virtual bool startOTAUpdate(const char* id, char reply[]) { return false; }   // not supported
+
+  // Power management interface (boards with power management override these)
+  virtual bool isExternalPowered() { return false; }
+  virtual uint16_t getBootVoltage() { return 0; }
+  virtual uint32_t getResetReason() const { return 0; }
+  virtual const char* getResetReasonString(uint32_t reason) { return "Not available"; }
+  virtual uint8_t getShutdownReason() const { return 0; }
+  virtual const char* getShutdownReasonString(uint8_t reason) { return "Not available"; }
 };
 
 /**

src/helpers/CommonCLI.cpp

@@ -364,6 +364,33 @@ void CommonCLI::handleCommand(uint32_t sender_timestamp, const char* command, ch
         } else {
           sprintf(reply, "> %.3f", adc_mult);
         }
+      // Power management commands
+      } else if (memcmp(config, "pwrmgt.support", 14) == 0) {
+#ifdef NRF52_POWER_MANAGEMENT
+        strcpy(reply, "> supported");
+#else
+        strcpy(reply, "> unsupported");
+#endif
+      } else if (memcmp(config, "pwrmgt.source", 13) == 0) {
+#ifdef NRF52_POWER_MANAGEMENT
+        strcpy(reply, _board->isExternalPowered() ? "> external" : "> battery");
+#else
+        strcpy(reply, "ERROR: Power management not supported");
+#endif
+      } else if (memcmp(config, "pwrmgt.bootreason", 17) == 0) {
+#ifdef NRF52_POWER_MANAGEMENT
+        sprintf(reply, "> Reset: %s; Shutdown: %s",
+          _board->getResetReasonString(_board->getResetReason()),
+          _board->getShutdownReasonString(_board->getShutdownReason()));
+#else
+        strcpy(reply, "ERROR: Power management not supported");
+#endif
+      } else if (memcmp(config, "pwrmgt.bootmv", 13) == 0) {
+#ifdef NRF52_POWER_MANAGEMENT
+        sprintf(reply, "> %u mV", _board->getBootVoltage());
+#else
+        strcpy(reply, "ERROR: Power management not supported");
+#endif
       } else {
         sprintf(reply, "??: %s", config);
       }

src/helpers/NRF52Board.cpp

@@ -2,6 +2,7 @@
 #include "NRF52Board.h"
 
 #include <bluefruit.h>
+#include <nrf_soc.h>
 
 static BLEDfu bledfu;
 
@@ -21,6 +22,222 @@ void NRF52Board::begin() {
   startup_reason = BD_STARTUP_NORMAL;
 }
 
+#ifdef NRF52_POWER_MANAGEMENT
+#include "nrf.h"
+
+// Power Management global variables
+uint32_t g_nrf52_reset_reason = 0;     // Reset/Startup reason
+uint8_t g_nrf52_shutdown_reason = 0;   // Shutdown reason
+
+// Early constructor - runs before SystemInit() clears the registers
+// Priority 101 ensures this runs before SystemInit (102) and before
+// any C++ static constructors (default 65535)
+static void __attribute__((constructor(101))) nrf52_early_reset_capture() {
+  g_nrf52_reset_reason = NRF_POWER->RESETREAS;
+  g_nrf52_shutdown_reason = NRF_POWER->GPREGRET2;
+}
+
+void NRF52Board::initPowerMgr() {
+  // Copy early-captured register values
+  reset_reason = g_nrf52_reset_reason;
+  shutdown_reason = g_nrf52_shutdown_reason;
+  boot_voltage_mv = 0;  // Will be set by checkBootVoltage()
+
+  // Clear registers for next boot
+  // Note: At this point SoftDevice may or may not be enabled
+  uint8_t sd_enabled = 0;
+  sd_softdevice_is_enabled(&sd_enabled);
+  if (sd_enabled) {
+    sd_power_reset_reason_clr(0xFFFFFFFF);
+    sd_power_gpregret_clr(1, 0xFF);
+  } else {
+    NRF_POWER->RESETREAS = 0xFFFFFFFF;  // Write 1s to clear
+    NRF_POWER->GPREGRET2 = 0;
+  }
+
+  // Log reset/shutdown info
+  if (shutdown_reason != SHUTDOWN_REASON_NONE) {
+    MESH_DEBUG_PRINTLN("PWRMGT: Reset = %s (0x%lX); Shutdown = %s (0x%02X)",
+      getResetReasonString(reset_reason), (unsigned long)reset_reason,
+      getShutdownReasonString(shutdown_reason), shutdown_reason);
+  } else {
+    MESH_DEBUG_PRINTLN("PWRMGT: Reset = %s (0x%lX)",
+      getResetReasonString(reset_reason), (unsigned long)reset_reason);
+  }
+}
+
+bool NRF52Board::isExternalPowered() {
+  // Check if SoftDevice is enabled before using its API
+  uint8_t sd_enabled = 0;
+  sd_softdevice_is_enabled(&sd_enabled);
+
+  if (sd_enabled) {
+    uint32_t usb_status;
+    sd_power_usbregstatus_get(&usb_status);
+    return (usb_status & POWER_USBREGSTATUS_VBUSDETECT_Msk) != 0;
+  } else {
+    return (NRF_POWER->USBREGSTATUS & POWER_USBREGSTATUS_VBUSDETECT_Msk) != 0;
+  }
+}
+
+const char* NRF52Board::getResetReasonString(uint32_t reason) {
+  if (reason & POWER_RESETREAS_RESETPIN_Msk) return "Reset Pin";
+  if (reason & POWER_RESETREAS_DOG_Msk) return "Watchdog";
+  if (reason & POWER_RESETREAS_SREQ_Msk) return "Soft Reset";
+  if (reason & POWER_RESETREAS_LOCKUP_Msk) return "CPU Lockup";
+  #ifdef POWER_RESETREAS_LPCOMP_Msk
+    if (reason & POWER_RESETREAS_LPCOMP_Msk) return "Wake from LPCOMP";
+  #endif
+  #ifdef POWER_RESETREAS_VBUS_Msk
+    if (reason & POWER_RESETREAS_VBUS_Msk) return "Wake from VBUS";
+  #endif
+  #ifdef POWER_RESETREAS_OFF_Msk
+    if (reason & POWER_RESETREAS_OFF_Msk) return "Wake from GPIO";
+  #endif
+  #ifdef POWER_RESETREAS_DIF_Msk
+    if (reason & POWER_RESETREAS_DIF_Msk) return "Debug Interface";
+  #endif
+  return "Cold Boot";
+}
+
+const char* NRF52Board::getShutdownReasonString(uint8_t reason) {
+  switch (reason) {
+    case SHUTDOWN_REASON_LOW_VOLTAGE:  return "Low Voltage";
+    case SHUTDOWN_REASON_USER:         return "User Request";
+    case SHUTDOWN_REASON_BOOT_PROTECT: return "Boot Protection";
+  }
+  return "Unknown";
+}
+
+bool NRF52Board::checkBootVoltage(const PowerMgtConfig* config) {
+  initPowerMgr();
+
+  // Read boot voltage
+  boot_voltage_mv = getBattMilliVolts();
+  
+  if (config->voltage_bootlock == 0) return true;  // Protection disabled
+
+  // Skip check if externally powered
+  if (isExternalPowered()) {
+    MESH_DEBUG_PRINTLN("PWRMGT: Boot check skipped (external power)");
+    boot_voltage_mv = getBattMilliVolts();
+    return true;
+  }
+
+  MESH_DEBUG_PRINTLN("PWRMGT: Boot voltage = %u mV (threshold = %u mV)",
+      boot_voltage_mv, config->voltage_bootlock);
+
+  // Only trigger shutdown if reading is valid (>1000mV) AND below threshold
+  // This prevents spurious shutdowns on ADC glitches or uninitialized reads
+  if (boot_voltage_mv > 1000 && boot_voltage_mv < config->voltage_bootlock) {
+    MESH_DEBUG_PRINTLN("PWRMGT: Boot voltage too low - entering protective shutdown");
+
+    initiateShutdown(SHUTDOWN_REASON_BOOT_PROTECT);
+    return false;  // Should never reach this
+  }
+
+  return true;
+}
+
+void NRF52Board::initiateShutdown(uint8_t reason) {
+  enterSystemOff(reason);
+}
+
+void NRF52Board::enterSystemOff(uint8_t reason) {
+  MESH_DEBUG_PRINTLN("PWRMGT: Entering SYSTEMOFF (%s)", getShutdownReasonString(reason));
+
+  // Record shutdown reason in GPREGRET2
+  uint8_t sd_enabled = 0;
+  sd_softdevice_is_enabled(&sd_enabled);
+  if (sd_enabled) {
+    sd_power_gpregret_clr(1, 0xFF);
+    sd_power_gpregret_set(1, reason);
+  } else {
+    NRF_POWER->GPREGRET2 = reason;
+  }
+
+  // Flush serial buffers
+  Serial.flush();
+  delay(100);
+
+  // Enter SYSTEMOFF
+  if (sd_enabled) {
+    uint32_t err = sd_power_system_off();
+    if (err == NRF_ERROR_SOFTDEVICE_NOT_ENABLED) {  //SoftDevice not enabled
+      sd_enabled = 0;
+    }
+  }
+
+  if (!sd_enabled) {
+    // SoftDevice not available; write directly to POWER->SYSTEMOFF
+    NRF_POWER->SYSTEMOFF = POWER_SYSTEMOFF_SYSTEMOFF_Enter;
+  }
+
+  // If we get here, something went wrong. Reset to recover.
+  NVIC_SystemReset();
+}
+
+void NRF52Board::configureVoltageWake(uint8_t ain_channel, uint8_t refsel) {
+  // LPCOMP is not managed by SoftDevice - direct register access required
+  // Halt and disable before reconfiguration
+  NRF_LPCOMP->TASKS_STOP = 1;
+  NRF_LPCOMP->ENABLE = LPCOMP_ENABLE_ENABLE_Disabled;
+
+  // Select analog input (AIN0-7 maps to PSEL 0-7)
+  NRF_LPCOMP->PSEL = ((uint32_t)ain_channel << LPCOMP_PSEL_PSEL_Pos) & LPCOMP_PSEL_PSEL_Msk;
+
+  // Reference: REFSEL (0-6=1/8..7/8, 7=ARef, 8-15=1/16..15/16)
+  NRF_LPCOMP->REFSEL = ((uint32_t)refsel << LPCOMP_REFSEL_REFSEL_Pos) & LPCOMP_REFSEL_REFSEL_Msk;
+
+  // Detect UP events (voltage rises above threshold for battery recovery)
+  NRF_LPCOMP->ANADETECT = LPCOMP_ANADETECT_ANADETECT_Up;
+
+  // Enable 50mV hysteresis for noise immunity
+  NRF_LPCOMP->HYST = LPCOMP_HYST_HYST_Hyst50mV;
+
+  // Clear stale events/interrupts before enabling wake
+  NRF_LPCOMP->EVENTS_READY = 0;
+  NRF_LPCOMP->EVENTS_DOWN = 0;
+  NRF_LPCOMP->EVENTS_UP = 0;
+  NRF_LPCOMP->EVENTS_CROSS = 0;
+
+  NRF_LPCOMP->INTENCLR = 0xFFFFFFFF;
+  NRF_LPCOMP->INTENSET = LPCOMP_INTENSET_UP_Msk;
+
+  // Enable LPCOMP
+  NRF_LPCOMP->ENABLE = LPCOMP_ENABLE_ENABLE_Enabled;
+  NRF_LPCOMP->TASKS_START = 1;
+
+  // Wait for comparator to settle before entering SYSTEMOFF
+  for (uint8_t i = 0; i < 20 && !NRF_LPCOMP->EVENTS_READY; i++) {
+    delayMicroseconds(50);
+  }
+
+  if (refsel == 7) {
+    MESH_DEBUG_PRINTLN("PWRMGT: LPCOMP wake configured (AIN%d, ref=ARef)", ain_channel);
+  } else if (refsel <= 6) {
+    MESH_DEBUG_PRINTLN("PWRMGT: LPCOMP wake configured (AIN%d, ref=%d/8 VDD)",
+      ain_channel, refsel + 1);
+  } else {
+    uint8_t ref_num = (uint8_t)((refsel - 8) * 2 + 1);
+    MESH_DEBUG_PRINTLN("PWRMGT: LPCOMP wake configured (AIN%d, ref=%d/16 VDD)",
+      ain_channel, ref_num);
+  }
+
+  // Configure VBUS (USB power) wake alongside LPCOMP
+  uint8_t sd_enabled = 0;
+  sd_softdevice_is_enabled(&sd_enabled);
+  if (sd_enabled) {
+    sd_power_usbdetected_enable(1);
+  } else {
+    NRF_POWER->EVENTS_USBDETECTED = 0;
+    NRF_POWER->INTENSET = POWER_INTENSET_USBDETECTED_Msk;
+  }
+
+  MESH_DEBUG_PRINTLN("PWRMGT: VBUS wake configured");
+}
+#endif
+
 void NRF52BoardDCDC::begin() {
   NRF52Board::begin();
 

src/helpers/NRF52Board.h

@@ -5,15 +5,58 @@
 
 #if defined(NRF52_PLATFORM)
 
+#ifdef NRF52_POWER_MANAGEMENT
+// Shutdown Reason Codes (stored in GPREGRET before SYSTEMOFF)
+#define SHUTDOWN_REASON_NONE          0x00
+#define SHUTDOWN_REASON_LOW_VOLTAGE   0x4C  // 'L' - Runtime low voltage threshold
+#define SHUTDOWN_REASON_USER          0x55  // 'U' - User requested powerOff()
+#define SHUTDOWN_REASON_BOOT_PROTECT  0x42  // 'B' - Boot voltage protection
+
+// Boards provide this struct with their hardware-specific settings and callbacks.
+struct PowerMgtConfig {
+  // LPCOMP wake configuration (for voltage recovery from SYSTEMOFF)
+  uint8_t lpcomp_ain_channel;       // AIN0-7 for voltage sensing pin
+  uint8_t lpcomp_refsel;            // REFSEL value: 0-6=1/8..7/8, 7=ARef, 8-15=1/16..15/16
+
+  // Boot protection voltage threshold (millivolts)
+  // Set to 0 to disable boot protection
+  uint16_t voltage_bootlock;
+};
+#endif
+
 class NRF52Board : public mesh::MainBoard {
+#ifdef NRF52_POWER_MANAGEMENT
+  void initPowerMgr();
+#endif
+
 protected:
   uint8_t startup_reason;
 
+#ifdef NRF52_POWER_MANAGEMENT
+  uint32_t reset_reason;              // RESETREAS register value
+  uint8_t shutdown_reason;            // GPREGRET value (why we entered last SYSTEMOFF)
+  uint16_t boot_voltage_mv;           // Battery voltage at boot (millivolts)
+
+  bool checkBootVoltage(const PowerMgtConfig* config);
+  void enterSystemOff(uint8_t reason);
+  void configureVoltageWake(uint8_t ain_channel, uint8_t refsel);
+  virtual void initiateShutdown(uint8_t reason);
+#endif
+
 public:
   virtual void begin();
   virtual uint8_t getStartupReason() const override { return startup_reason; }
   virtual float getMCUTemperature() override;
   virtual void reboot() override { NVIC_SystemReset(); }
+
+#ifdef NRF52_POWER_MANAGEMENT
+  bool isExternalPowered() override;
+  uint16_t getBootVoltage() override { return boot_voltage_mv; }
+  virtual uint32_t getResetReason() const override { return reset_reason; }
+  uint8_t getShutdownReason() const override { return shutdown_reason; }
+  const char* getResetReasonString(uint32_t reason) override;
+  const char* getShutdownReasonString(uint8_t reason) override;
+#endif
 };
 
 /*