Differences

This shows you the differences between two versions of the page.

--- manual:ports:armcm4_stm32 [2019/09/24 22:12]
127.0.0.1 external edit
+++ manual:ports:armcm4_stm32 [2022/11/07 11:28] (current)
voorburg [Checksum location]
@@ Line 15: / Line 15: @@
 In case you want to manually change the size of the bootloader, make sure the size is aligned to the sectors as outlined in the flashLayout[] array in file flash.c. For the STM32F4xx targets, the first sector is 0x4000 (16 kbyte) in size, which is also the smallest erase size of the flash memory. This means that even though a bootloader, configured to just use one communication interface, can fit in about 6 kbyte, on STM32F4xx targets the minimal bootloader size is still 16 kbyte.
-Because the bootloader remaps the base address of the interrupt vector table, make sure that your program's initialization routine does not set it back to its original location. This is the case if you use function SystemInit() from ST's driver library. To correct this you need to remove the following lines from function SystemInit():
+Before the bootloader starts your firmware, it automatically reconfigured the start address of the interrupt vector table. Unfortunately, the default system initialization function SystemInit() from ST's driver library, overwrites this change. This function is implemented in source file system_stm32f4xx.c. To correct this you need to explicitly set the start address of the interrupt vector table as the first thing in function main(). Here is an example of how this can be done when using STM32CubeIDE:
-<code>
+Add the following function to main.c:
-#ifdef VECT_TAB_SRAM
-  SCB->VTOR = SRAM_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal SRAM. */
-#else
-  SCB->VTOR = FLASH_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal FLASH. */
-#endif
-</code>
+<code c>
+static void VectorBase_Config(void)
+{
+  /* The constant array with vectors of the vector table is declared externally in the
+   * c-startup code.
+   */
+  extern const unsigned long g_pfnVectors[];
+  /* Remap the vector table to where the vector table is located for this program. */
+  SCB->VTOR = (unsigned long)&g_pfnVectors[0];
+}
+</code>
+And call this newly added function at the start of main():
+<code c>
+int main(void)
+{
+  /* Configure the vector table base address. */
+  VectorBase_Config();
+  ...
+}
+</code>
 ===== Checksum location =====
@@ Line 33: / Line 49: @@
 A 32-bit checksum value is programmed by the bootloader at the end of a programming session. Upon startup, the bootloader verifies the correctness of this checksum to determine if a valid user program is present and can be started.
-The bootloader programs this value at the end of the user program's vector table. Its exact location is configured by macro FLASH_VECTOR_TABLE_CS_OFFSET in flash.c. The vector table size can vary based on the microcontroller derivative you are using. Please verify that the default value of FLASH_VECTOR_TABLE_CS_OFFSET is correct. If not, you can simply override the value by adding the macro with the correct value to the blt_conf.h configuration header file.
+The bootloader programs this value at the end of the user program's vector table. Its exact location is configured by macro BOOT_FLASH_VECTOR_TABLE_CS_OFFSET in flash.c. The vector table size can vary based on the microcontroller derivative you are using. Please verify that the default value of BOOT_FLASH_VECTOR_TABLE_CS_OFFSET is correct. If not, you can simply override the value by adding the macro with the correct value to the blt_conf.h configuration header file.
 The user program must reserve space for this 32-bit checksum value. To reserve this space, simply enter one extra dummy entry into the interrupt vector table. This reserves space for the checksum at memory address: flash base address + flash reserved for bootloader  + FLASH_VECTOR_TABLE_CS_OFFSET. Refer to the demo program for an example.

OpenBLT Bootloader

User Tools

Site Tools

Differences

Page Tools