Added time keeping for NRF52 across resets

boards/nrf52840_s140_v6.ld

@@ -7,18 +7,29 @@ MEMORY
 {
   FLASH (rx)     : ORIGIN = 0x26000, LENGTH = 0xED000 - 0x26000
 
+  /* To keep data in RAM across resets */
+  PERSISTENT_RAM (rwx) : ORIGIN = 0x20006000, LENGTH = 8
+
   /* SRAM required by Softdevice depend on
    * - Attribute Table Size (Number of Services and Characteristics)
    * - Vendor UUID count
    * - Max ATT MTU
    * - Concurrent connection peripheral + central + secure links
    * - Event Len, HVN queue, Write CMD queue
    */ 
-  RAM (rwx) :  ORIGIN = 0x20006000, LENGTH = 0x20040000 - 0x20006000
+  RAM (rwx) :  ORIGIN = 0x20006000 + 8, LENGTH = 0x20040000 - 0x20006000 - 8
 }
 
 SECTIONS
 {
+  . = ALIGN(4);
+  .persistent (NOLOAD) :
+  {
+    KEEP(*(.persistent_magic))
+    KEEP(*(.persistent_data))
+    . = ALIGN(4);
+  } > PERSISTENT_RAM
+
   . = ALIGN(4);
   .svc_data :
   {
@@ -33,6 +44,6 @@ SECTIONS
     KEEP(*(.fs_data))
     PROVIDE(__stop_fs_data = .);
   } > RAM
-} INSERT AFTER .data;
+}
 
 INCLUDE "nrf52_common.ld"

boards/nrf52840_s140_v6_extrafs.ld

@@ -7,18 +7,29 @@ MEMORY
 {
   FLASH (rx)     : ORIGIN = 0x26000, LENGTH = 0xD4000 - 0x26000
 
+  /* To keep data in RAM across resets */
+  PERSISTENT_RAM (rwx) : ORIGIN = 0x20006000, LENGTH = 8
+
   /* SRAM required by Softdevice depend on
    * - Attribute Table Size (Number of Services and Characteristics)
    * - Vendor UUID count
    * - Max ATT MTU
    * - Concurrent connection peripheral + central + secure links
    * - Event Len, HVN queue, Write CMD queue
    */ 
-  RAM (rwx) :  ORIGIN = 0x20006000, LENGTH = 0x20040000 - 0x20006000
+  RAM (rwx) :  ORIGIN = 0x20006000 + 8, LENGTH = 0x20040000 - 0x20006000 - 8
 }
 
 SECTIONS
 {
+  . = ALIGN(4);
+  .persistent (NOLOAD) :
+  {
+    KEEP(*(.persistent_magic))
+    KEEP(*(.persistent_data))
+    . = ALIGN(4);
+  } > PERSISTENT_RAM
+
   . = ALIGN(4);
   .svc_data :
   {
@@ -33,6 +44,6 @@ SECTIONS
     KEEP(*(.fs_data))
     PROVIDE(__stop_fs_data = .);
   } > RAM
-} INSERT AFTER .data;
+}
 
 INCLUDE "nrf52_common.ld"

boards/nrf52840_s140_v7.ld

@@ -7,18 +7,29 @@ MEMORY
 {
   FLASH (rx)     : ORIGIN = 0x27000, LENGTH = 0xED000 - 0x27000
 
+  /* To keep data in RAM across resets */
+  PERSISTENT_RAM (rwx) : ORIGIN = 0x20006000, LENGTH = 8
+
   /* SRAM required by Softdevice depend on
    * - Attribute Table Size (Number of Services and Characteristics)
    * - Vendor UUID count
    * - Max ATT MTU
    * - Concurrent connection peripheral + central + secure links
    * - Event Len, HVN queue, Write CMD queue
    */ 
-  RAM (rwx) :  ORIGIN = 0x20006000, LENGTH = 0x20040000 - 0x20006000
+  RAM (rwx) :  ORIGIN = 0x20006000 + 8, LENGTH = 0x20040000 - 0x20006000 - 8
 }
 
 SECTIONS
 {
+  . = ALIGN(4);
+  .persistent (NOLOAD) :
+  {
+    KEEP(*(.persistent_magic))
+    KEEP(*(.persistent_data))
+    . = ALIGN(4);
+  } > PERSISTENT_RAM
+
   . = ALIGN(4);
   .svc_data :
   {
@@ -33,6 +44,6 @@ SECTIONS
     KEEP(*(.fs_data))
     PROVIDE(__stop_fs_data = .);
   } > RAM
-} INSERT AFTER .data;
+}
 
 INCLUDE "nrf52_common.ld"

boards/nrf52840_s140_v7_extrafs.ld

@@ -14,11 +14,19 @@ MEMORY
    * - Concurrent connection peripheral + central + secure links
    * - Event Len, HVN queue, Write CMD queue
    */ 
-  RAM (rwx) :  ORIGIN = 0x20006000, LENGTH = 0x20040000 - 0x20006000
+  RAM (rwx) :  ORIGIN = 0x20006000 + 8, LENGTH = 0x20040000 - 0x20006000 - 8
 }
 
 SECTIONS
 {
+  . = ALIGN(4);
+  .persistent (NOLOAD) :
+  {
+    KEEP(*(.persistent_magic))
+    KEEP(*(.persistent_data))
+    . = ALIGN(4);
+  } > PERSISTENT_RAM
+
   . = ALIGN(4);
   .svc_data :
   {
@@ -33,6 +41,6 @@ SECTIONS
     KEEP(*(.fs_data))
     PROVIDE(__stop_fs_data = .);
   } > RAM
-} INSERT AFTER .data;
+}
 
 INCLUDE "nrf52_common.ld"

src/helpers/ArduinoHelpers.cpp

@@ -0,0 +1,6 @@
+#include <stdint.h>
+
+extern "C" {
+    __attribute__((section(".persistent_magic"))) uint32_t persistent_magic;
+    __attribute__((section(".persistent_data"))) uint32_t persistent_time;
+}

src/helpers/ArduinoHelpers.h

@@ -3,19 +3,57 @@
 #include <Mesh.h>
 #include <Arduino.h>
 
+#ifdef NRF52_PLATFORM
+#define CLOCK_MAGIC_NUM        0xAA55CC33
+#define RTC_TIME_MIN           1772323200  // 1 Mar 2026
+
+extern uint32_t persistent_magic;
+extern uint32_t persistent_time;
+#endif
+
 class VolatileRTCClock : public mesh::RTCClock {
   uint32_t base_time;
   uint64_t accumulator;
   unsigned long prev_millis;
+
 public:
-  VolatileRTCClock() { base_time = 1715770351; accumulator = 0; prev_millis = millis(); }   // 15 May 2024, 8:50pm
+  VolatileRTCClock() {
+#ifdef NRF52_PLATFORM
+    if (persistent_magic == CLOCK_MAGIC_NUM && persistent_time >= RTC_TIME_MIN) {
+      base_time = persistent_time;
+    } else {
+      base_time = RTC_TIME_MIN;
+    }
+#else
+    base_time = 1715770351;
+#endif
+
+    accumulator = 0;
+    prev_millis = millis();
+  }
+
   uint32_t getCurrentTime() override { return base_time + accumulator/1000; }
-  void setCurrentTime(uint32_t time) override { base_time = time; accumulator = 0; prev_millis = millis(); }
+
+  void setCurrentTime(uint32_t time) override {
+    base_time = time;
+    accumulator = 0;
+    prev_millis = millis();
+
+#ifdef NRF52_PLATFORM
+    persistent_magic = CLOCK_MAGIC_NUM;
+    persistent_time = time;
+#endif
+  }
 
   void tick() override {
     unsigned long now = millis();
     accumulator += (now - prev_millis);
     prev_millis = now;
+
+#ifdef NRF52_PLATFORM
+    persistent_magic = CLOCK_MAGIC_NUM;
+    persistent_time = getCurrentTime();
+#endif
   }
 };
 

variants/gat562_30s_mesh_kit/platformio.ini

@@ -2,6 +2,7 @@
 extends = nrf52_base
 board = rak4631
 board_check = true
+board_build.ldscript = boards/nrf52840_s140_v6.ld
 build_flags = ${nrf52_base.build_flags}
   ${sensor_base.build_flags}
   -I variants/gat562_30s_mesh_kit

variants/gat562_mesh_tracker_pro/platformio.ini

@@ -2,6 +2,7 @@
 extends = nrf52_base
 board = rak4631
 board_check = true
+board_build.ldscript = boards/nrf52840_s140_v6.ld
 build_flags = ${nrf52_base.build_flags}
   ${sensor_base.build_flags}
   -I variants/gat562_mesh_tracker_pro

variants/promicro/platformio.ini

@@ -1,6 +1,7 @@
 [Promicro]
 extends = nrf52_base
 board = promicro_nrf52840
+board_build.ldscript = boards/nrf52840_s140_v6.ld
 build_flags = ${nrf52_base.build_flags}
   -I variants/promicro
   -D PROMICRO

variants/rak3401/platformio.ini

@@ -2,6 +2,7 @@
 extends = nrf52_base
 board = rak3401
 board_check = true
+board_build.ldscript = boards/nrf52840_s140_v6.ld
 build_flags = ${nrf52_base.build_flags}
   ${sensor_base.build_flags}
   -I variants/rak3401

variants/rak4631/platformio.ini

@@ -2,6 +2,7 @@
 extends = nrf52_base
 board = rak4631
 board_check = true
+board_build.ldscript = boards/nrf52840_s140_v6.ld
 extra_scripts = ${nrf52_base.extra_scripts}
   post:variants/rak4631/fix_bsec_lib.py
 build_flags = ${nrf52_base.build_flags}

variants/rak_wismesh_tag/platformio.ini

@@ -2,6 +2,7 @@
 extends = nrf52_base
 board = rak4631
 board_check = true
+board_build.ldscript = boards/nrf52840_s140_v6.ld
 build_flags = ${nrf52_base.build_flags}
   ${sensor_base.build_flags}
   -I variants/rak_wismesh_tag