Implement a bootloader.

This bootloader is now the application at 0x08000000 (FLASH start),
which the STM32 will execute upon reset.

The other applications are now loaded at 0x08030000 (128 KB into the
flash) and will never get started unless the bootloader has been
programmed into flash too.

1 files changed, 4 insertions, 5 deletions

diff --git a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_CRYPTECH_ALPHA/system_stm32f4xx.c b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_CRYPTECH_ALPHA/system_stm32f4xx.c
index cc527ae..2824fd6 100644
--- a/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_CRYPTECH_ALPHA/system_stm32f4xx.c
+++ b/libraries/mbed/targets/cmsis/TARGET_STM/TARGET_STM32F4/TARGET_CRYPTECH_ALPHA/system_stm32f4xx.c
@@ -75,8 +75,6 @@
   #define HSI_VALUE    ((uint32_t)16000000) /*!< Value of the Internal oscillator in Hz*/
 #endif /* HSI_VALUE */
 
-extern uint32_t CRYPTECH_FIRMWARE_START;  /* defined in the linker script (STM32F429BI.ld) */
-
 /**
   * @}
   */
@@ -200,13 +198,14 @@ void SystemInit(void)
 
   /* Configure the Vector Table location add offset address ------------------*/
   /* cryptech: Don't change VTOR if it is already set up by the bootloader */
-  if (SCB->VTOR != CRYPTECH_FIRMWARE_START) {
 #ifdef VECT_TAB_SRAM
-      SCB->VTOR = SRAM_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal SRAM */
+  SCB->VTOR = SRAM_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal SRAM */
 #else
+  /* Set up VTOR unless it has already been set by the bootloader. */
+  if (! SCB->VTOR) {
       SCB->VTOR = FLASH_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal FLASH */
-#endif
   }
+#endif
 
   /* Configure the Cube driver */
   SystemCoreClock = 16000000; // At this stage the HSI is used as system clock