Adafruit Grand Central M4 (#14749)

Marlin/src/gcode/calibrate/M100.cpp

@@ -75,7 +75,7 @@
 
   char *end_bss = &__bss_end__,
        *stacklimit = &__StackLimit,
-       *heaplimit = &__HeapLimit ;
+       *heaplimit = &__HeapLimit;
 
   #define MEMORY_END_CORRECTION 0x200
 
@@ -94,6 +94,20 @@
 
   #define MEMORY_END_CORRECTION 0x10000  // need to stay well below 0x20080000 or M100 F crashes
 
+#elif defined(__SAMD51__)
+
+  extern unsigned int __bss_end__, __StackLimit, __HeapLimit;
+  extern "C" void * _sbrk(int incr);
+
+  void *end_bss = &__bss_end__,
+       *stacklimit = &__StackLimit,
+       *heaplimit = &__HeapLimit;
+
+  #define MEMORY_END_CORRECTION 0x400
+
+  char *free_memory_start = (char *)_sbrk(0) + 0x200,     //  Leave some heap space
+       *free_memory_end = (char *)stacklimit - MEMORY_END_CORRECTION;
+
 #else
   #error "M100 - unsupported CPU"
 #endif