[bl] Fixing the jump to sketch

bootloaders/zero/Makefile

@@ -65,9 +65,9 @@ SIZE=$(ARM_GCC_PATH)size
 #-w
 CFLAGS=-mthumb -mcpu=cortex-m0plus -Wall -c -std=gnu99 -ffunction-sections -fdata-sections -nostdlib -nostartfiles --param max-inline-insns-single=500
 ifdef DEBUG
-CFLAGS+=-g3 -O1
+CFLAGS+=-g3 -O1 -DDEBUG=1
 else
-CFLAGS+=-Os
+CFLAGS+=-Os -DDEBUG=0
 endif
 #CFLAGS_EXTRA?=-D__SAMD21G18A__ -DUSB_PID_LOW=0x4D -DUSB_PID_HIGH=0x00
 CFLAGS_EXTRA?=-D__SAMD21J18A__ -DUSB_PID_LOW=0x01 -DUSB_PID_HIGH=0xE0
@@ -153,8 +153,9 @@ copy_for_atmel_studio: $(EXECUTABLE)
 
 clean_for_atmel_studio:
 	@echo ----------------------------------------------------------
-	@echo Atmel Studio detected, cleaing ELF from project root
-	-$(RM) $(BUILD_PATH)/$(ELF) .
+	@echo Atmel Studio detected, cleaning ELF from project root
+#	-$(RM) $(BUILD_PATH)/$(ELF)
+	-$(RM) ./$(ELF)
 
 clean: $(AS_CLEAN)
 	@echo ----------------------------------------------------------

bootloaders/zero/bootloader_samd21x18.ld

@@ -58,7 +58,7 @@ MEMORY
  *   __StackLimit
  *   __StackTop
  *   __stack
- *   __app_start_address
+ *   __sketch_stackptr
  */
 ENTRY(Reset_Handler)
 
@@ -144,7 +144,7 @@ SECTIONS
 	*/
 
 	__etext = .;
-  PROVIDE(__app_start_address = ORIGIN(FLASH) + LENGTH(FLASH));
+  PROVIDE(__sketch_stackptr = ORIGIN(FLASH) + LENGTH(FLASH));
 
 
 	.data : AT (__etext)

bootloaders/zero/main.c

@@ -70,10 +70,12 @@
 #include "sam_ba_usb.h"
 #include "sam_ba_cdc.h"
 
-extern uint32_t __app_start_address;
+extern uint32_t __sketch_stackptr; // Exported value from linker script
 extern void board_init(void);
 
-//static void check_start_application(void);
+#if (defined DEBUG) && (DEBUG == 1)
+volatile uint32_t* pulSketch_Start_Address;
+#endif
 
 static volatile bool main_b_cdc_enable = false;
 
@@ -105,7 +107,9 @@ static void check_start_application(void)
     /* First tap */
     BOOT_DOUBLE_TAP_DATA = DOUBLE_TAP_MAGIC;
 
-    /* Wait 0.5sec to see if the user tap reset again */
+    /* Wait 0.5sec to see if the user tap reset again.
+     * The loop value is based on SAMD21 default 1MHz clock @ reset.
+     */
     for (uint32_t i=0; i<125000; i++) /* 500ms */
       /* force compiler to not optimize this... */
       __asm__ __volatile__("");
@@ -115,51 +119,71 @@ static void check_start_application(void)
   }
 #endif
 
-  uint32_t app_start_address;
+#if (!defined DEBUG) || ((defined DEBUG) && (DEBUG == 0))
+uint32_t* pulSketch_Start_Address;
+#endif
 
-  /* Load the Reset Handler address of the application */
-  app_start_address = *(uint32_t *)(&__app_start_address + 4);
+  /*
+   * Test sketch stack pointer @ &__sketch_stackptr
+   * Stay in SAM-BA if value @ (&__sketch_stackptr) == 0xFFFFFFFF (Erased flash cell value)
+   */
+  if (__sketch_stackptr == 0xFFFFFFFF)
+  {
+    /* Stay in bootloader */
+    return;
+  }
+ 
+  /* 
+   * Load the sketch Reset Handler address
+   * __sketch_stackptr is exported from linker script and point on first 32b word of sketch vector table
+   * First 32b word is sketch stack
+   * Second 32b word is sketch entry point: Reset_Handler()
+   */
+  pulSketch_Start_Address = &__sketch_stackptr ;
+  pulSketch_Start_Address++ ;
 
-  /**
-   * Test reset vector of application @__app_start_address+4
-   * Stay in SAM-BA if *(__app_start_address+0x4) == 0xFFFFFFFF
-   * Application erased condition
+  /*
+   * Test reset vector of sketch @ &__sketch_stackptr+4
+   * Stay in SAM-BA if this function is not aligned enough, ie not valid
+   * The value 0x01 is the 'Thumb mode' bit added by linker.
    */
-  if (app_start_address == 0xFFFFFFFF)
+  if ( (*pulSketch_Start_Address & ~SCB_VTOR_TBLOFF_Msk) != 0x01 )
   {
     /* Stay in bootloader */
     return;
   }
 
+/*
 #if defined(BOOT_LOAD_PIN)
   volatile PortGroup *boot_port = (volatile PortGroup *)(&(PORT->Group[BOOT_LOAD_PIN / 32]));
   volatile bool boot_en;
 
-  /* Enable the input mode in Boot GPIO Pin */
+  // Enable the input mode in Boot GPIO Pin
   boot_port->DIRCLR.reg = BOOT_PIN_MASK;
   boot_port->PINCFG[BOOT_LOAD_PIN & 0x1F].reg = PORT_PINCFG_INEN | PORT_PINCFG_PULLEN;
   boot_port->OUTSET.reg = BOOT_PIN_MASK;
-  /* Read the BOOT_LOAD_PIN status */
+  // Read the BOOT_LOAD_PIN status
   boot_en = (boot_port->IN.reg) & BOOT_PIN_MASK;
 
-  /* Check the bootloader enable condition */
+  // Check the bootloader enable condition
   if (!boot_en)
   {
-    /* Stay in bootloader */
+    // Stay in bootloader
     return;
   }
 #endif
+*/
 
   LED_on();
 
   /* Rebase the Stack Pointer */
-  __set_MSP(*(uint32_t *) &__app_start_address);
+  __set_MSP( (uint32_t)(*(pulSketch_Start_Address-1)) );
 
   /* Rebase the vector table base address */
-  SCB->VTOR = ((uint32_t) &__app_start_address & SCB_VTOR_TBLOFF_Msk);
+  SCB->VTOR = ((uint32_t)(pulSketch_Start_Address-1) & SCB_VTOR_TBLOFF_Msk);
 
   /* Jump to application Reset Handler in the application */
-  asm("bx %0"::"r"(app_start_address));
+  asm("bx %0"::"r"(*pulSketch_Start_Address));
 }
 
 #if DEBUG_ENABLE

bootloaders/zero/samd21_sam_ba.cproj

@@ -69,10 +69,6 @@
       <Value>NDEBUG</Value>
     </ListValues>
   </armgcc.compiler.symbols.DefSymbols>
-  <armgcc.compiler.directories.IncludePaths>
-    <ListValues>
-    </ListValues>
-  </armgcc.compiler.directories.IncludePaths>
   <armgcc.compiler.optimization.level>Optimize for size (-Os)</armgcc.compiler.optimization.level>
   <armgcc.compiler.optimization.PrepareFunctionsForGarbageCollection>True</armgcc.compiler.optimization.PrepareFunctionsForGarbageCollection>
   <armgcc.compiler.warnings.AllWarnings>True</armgcc.compiler.warnings.AllWarnings>
@@ -81,16 +77,8 @@
       <Value>libm</Value>
     </ListValues>
   </armgcc.linker.libraries.Libraries>
-  <armgcc.linker.libraries.LibrarySearchPaths>
-    <ListValues>
-    </ListValues>
-  </armgcc.linker.libraries.LibrarySearchPaths>
   <armgcc.linker.optimization.GarbageCollectUnusedSections>True</armgcc.linker.optimization.GarbageCollectUnusedSections>
   <armgcc.linker.miscellaneous.LinkerFlags>-Tsamd21j18a_flash.ld</armgcc.linker.miscellaneous.LinkerFlags>
-  <armgcc.preprocessingassembler.general.IncludePaths>
-    <ListValues>
-    </ListValues>
-  </armgcc.preprocessingassembler.general.IncludePaths>
 </ArmGcc>
     </ToolchainSettings>
   </PropertyGroup>
@@ -107,10 +95,6 @@
       <Value>DEBUG</Value>
     </ListValues>
   </armgcc.compiler.symbols.DefSymbols>
-  <armgcc.compiler.directories.IncludePaths>
-    <ListValues>
-    </ListValues>
-  </armgcc.compiler.directories.IncludePaths>
   <armgcc.compiler.optimization.level>Optimize (-O1)</armgcc.compiler.optimization.level>
   <armgcc.compiler.optimization.PrepareFunctionsForGarbageCollection>True</armgcc.compiler.optimization.PrepareFunctionsForGarbageCollection>
   <armgcc.compiler.optimization.DebugLevel>Maximum (-g3)</armgcc.compiler.optimization.DebugLevel>
@@ -120,17 +104,9 @@
       <Value>libm</Value>
     </ListValues>
   </armgcc.linker.libraries.Libraries>
-  <armgcc.linker.libraries.LibrarySearchPaths>
-    <ListValues>
-    </ListValues>
-  </armgcc.linker.libraries.LibrarySearchPaths>
   <armgcc.linker.optimization.GarbageCollectUnusedSections>True</armgcc.linker.optimization.GarbageCollectUnusedSections>
   <armgcc.linker.miscellaneous.LinkerFlags>-Tsamd21j18a_flash.ld</armgcc.linker.miscellaneous.LinkerFlags>
   <armgcc.assembler.debugging.DebugLevel>Default (-g)</armgcc.assembler.debugging.DebugLevel>
-  <armgcc.preprocessingassembler.general.IncludePaths>
-    <ListValues>
-    </ListValues>
-  </armgcc.preprocessingassembler.general.IncludePaths>
   <armgcc.preprocessingassembler.debugging.DebugLevel>Default (-Wa,-g)</armgcc.preprocessingassembler.debugging.DebugLevel>
 </ArmGcc>
     </ToolchainSettings>
@@ -241,4 +217,4 @@
     </None>
   </ItemGroup>
   <Import Project="$(AVRSTUDIO_EXE_PATH)\\Vs\\Compiler.targets" />
-</Project>
+</Project>
\ No newline at end of file