Expose address that marks the usable top of flash memory

Author: finneyj

inc/MicroBitConfig.h

@@ -68,7 +68,11 @@
 #endif
 
 #ifndef MICROBIT_DEFAULT_SCRATCH_PAGE
-    #define MICROBIT_DEFAULT_SCRATCH_PAGE   ( MICROBIT_BOOTLOADER_ADDRESS - MICROBIT_CODEPAGESIZE * 4)
+    #ifdef SOFTDEVICE_PRESENT
+        #define MICROBIT_DEFAULT_SCRATCH_PAGE   ( MICROBIT_BOOTLOADER_ADDRESS - MICROBIT_CODEPAGESIZE * 4)
+    #else
+        #define MICROBIT_DEFAULT_SCRATCH_PAGE   ( 0x7E000 )
+    #endif
 #endif
 
 #ifndef MICROBIT_STORAGE_SCRATCH_PAGE
@@ -87,6 +91,9 @@
     #endif
 #endif
 
+#ifndef MICROBIT_TOP_OF_FLASH
+    #define MICROBIT_TOP_OF_FLASH           ( MICROBIT_DEFAULT_SCRATCH_PAGE )
+#endif
 
 #ifndef MICROBIT_APP_REGION_END
     #define MICROBIT_APP_REGION_END         ( MICROBIT_DEFAULT_SCRATCH_PAGE)

model/MicroBit.cpp

@@ -474,3 +474,8 @@ void microbit_dmesg_flush()
 #endif
 }
 
+uint32_t *microbit_top_of_flash()
+{
+    return (uint32_t *) MICROBIT_TOP_OF_FLASH;
+}
+

model/MicroBit.h

@@ -316,6 +316,7 @@ namespace codal
 }
 
 void microbit_dmesg_flush();
+uint32_t *microbit_top_of_flash();
 
 #if CONFIG_ENABLED(CODAL_USE_GLOBAL_NAMESPACE)
 using namespace codal;