modification to .ld to improve memory

Author: Roberto Spelta

targets/TARGET_STM/TARGET_STM32L4/TARGET_STM32L476xG/TARGET_SILICA_SENSOR_NODE/device/TOOLCHAIN_GCC_ARM/STM32L476XX.ld

@@ -6,6 +6,9 @@
   #define MBED_APP_SIZE 1024k
 #endif
 
+STACK_SIZE = 0x400;
+HEAP_SIZE = 0x7800;
+
 /* Linker script to configure memory regions. */
 MEMORY
 { 
@@ -86,6 +89,11 @@ SECTIONS
     __etext = .;
     _sidata = .;
 
+    .mesh_heap (COPY):
+    {
+        *(mesh_heap*)
+    } > SRAM2
+
     .data : AT (__etext)
     {
         __data_start__ = .;
@@ -138,7 +146,7 @@ SECTIONS
     {
         __end__ = .;
         end = __end__;
-        *(.heap*)
+        . += HEAP_SIZE;
         __HeapLimit = .;
     } > SRAM1
 
@@ -154,7 +162,7 @@ SECTIONS
      * size of stack_dummy section */
     __StackTop = ORIGIN(SRAM1) + LENGTH(SRAM1);
     _estack = __StackTop;
-    __StackLimit = __StackTop - SIZEOF(.stack_dummy);
+    __StackLimit = __StackTop - STACK_SIZE;
     PROVIDE(__stack = __StackTop);
 
     /* Check if data + heap + stack exceeds RAM limit */