From 2384af19b678eab97178a2e052cbaf709001324a Mon Sep 17 00:00:00 2001
From: Kevin Le <vinhdat82@gmail.com>
Date: Wed, 12 Aug 2026 19:29:49 +0700
Subject: [PATCH] RAM slot to keep time for NRF52

---
 boards/nrf52840_s140_v6.ld         | 15 +++++++++++++--
 boards/nrf52840_s140_v6_extrafs.ld | 15 +++++++++++++--
 boards/nrf52840_s140_v7.ld         | 15 +++++++++++++--
 boards/nrf52840_s140_v7_extrafs.ld | 15 +++++++++++++--
 4 files changed, 52 insertions(+), 8 deletions(-)

diff --git a/boards/nrf52840_s140_v6.ld b/boards/nrf52840_s140_v6.ld
index 6dad975b..d0c7d1dc 100644
--- a/boards/nrf52840_s140_v6.ld
+++ b/boards/nrf52840_s140_v6.ld
@@ -7,6 +7,9 @@ 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
@@ -14,11 +17,19 @@ 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 +44,6 @@ SECTIONS
     KEEP(*(.fs_data))
     PROVIDE(__stop_fs_data = .);
   } > RAM
-} INSERT AFTER .data;
+}
 
 INCLUDE "nrf52_common.ld"
diff --git a/boards/nrf52840_s140_v6_extrafs.ld b/boards/nrf52840_s140_v6_extrafs.ld
index 35261067..bd454747 100644
--- a/boards/nrf52840_s140_v6_extrafs.ld
+++ b/boards/nrf52840_s140_v6_extrafs.ld
@@ -7,6 +7,9 @@ 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
@@ -14,11 +17,19 @@ 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 +44,6 @@ SECTIONS
     KEEP(*(.fs_data))
     PROVIDE(__stop_fs_data = .);
   } > RAM
-} INSERT AFTER .data;
+}
 
 INCLUDE "nrf52_common.ld"
diff --git a/boards/nrf52840_s140_v7.ld b/boards/nrf52840_s140_v7.ld
index 6aaeb403..2333238f 100644
--- a/boards/nrf52840_s140_v7.ld
+++ b/boards/nrf52840_s140_v7.ld
@@ -7,6 +7,9 @@ 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
@@ -14,11 +17,19 @@ 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 +44,6 @@ SECTIONS
     KEEP(*(.fs_data))
     PROVIDE(__stop_fs_data = .);
   } > RAM
-} INSERT AFTER .data;
+}
 
 INCLUDE "nrf52_common.ld"
diff --git a/boards/nrf52840_s140_v7_extrafs.ld b/boards/nrf52840_s140_v7_extrafs.ld
index 5956183a..ef6ebba1 100644
--- a/boards/nrf52840_s140_v7_extrafs.ld
+++ b/boards/nrf52840_s140_v7_extrafs.ld
@@ -7,6 +7,9 @@ MEMORY
 {
   FLASH (rx)     : ORIGIN = 0x27000, LENGTH = 0xD4000 - 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
@@ -14,11 +17,19 @@ 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 +44,6 @@ SECTIONS
     KEEP(*(.fs_data))
     PROVIDE(__stop_fs_data = .);
   } > RAM
-} INSERT AFTER .data;
+}
 
 INCLUDE "nrf52_common.ld"