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Why STM32F103VDT6 Isn’t Writing to Flash and How to Fix It

Why STM32F103VDT6 Isn’t Writing to Flash and How to Fix It

The STM32F103 VDT6 microcontroller is widely used for embedded systems, but sometimes, developers face issues with writing data to its Flash Memory . If you're encountering problems where the STM32F103VDT6 isn’t writing to Flash, there could be several potential causes for this behavior. Let’s break down the common reasons for this issue and provide step-by-step solutions.

Potential Causes of Flash Writing Failure

Incorrect Flash Programming Sequence STM32 microcontrollers have a specific sequence that must be followed to successfully write data to Flash. If this sequence is violated, Flash programming will fail.

Write Protection Enabled The STM32F103 series allows enabling write protection for specific sectors of the Flash memory. If the write protection is enabled on the sector you're trying to write to, the operation will fail.

Flash Erase Not Performed Before writing data to Flash, it is necessary to erase the target sector. If you try to write without erasing the Flash memory first, the process will fail.

Flash Memory is Locked STM32 microcontrollers can lock the Flash memory to prevent writing during runtime. If the memory is locked, you won’t be able to write data until it's unlocked.

Voltage Supply Issues Flash programming requires stable Power . If the voltage supply to the STM32F103 is unstable or too low, it could cause failures when attempting to write to Flash.

Wrong Peripheral Settings Using incorrect or improperly configured peripheral settings, such as clocks or voltage levels for Flash operations, can prevent successful Flash writes.

How to Fix the Flash Writing Issue: A Step-by-Step Guide Ensure Correct Flash Programming Sequence The STM32 microcontroller requires a specific sequence to unlock, erase, and write to Flash. Make sure you're following this procedure: Unlock the Flash: Use the FLASH_Unlock() function to unlock the Flash memory before performing any operations. Erase the Flash Sector: Use the FLASH_EraseSector() function to erase the sector where you want to write. Ensure you're erasing the correct sector. Write Data to Flash: After erasing, use the FLASH_Program() function to write the desired data. Lock the Flash: Once writing is done, use the FLASH_Lock() function to lock the Flash memory for security. Disable Write Protection Check if write protection is enabled on the sector you are trying to write to. If it is, you need to disable it: Use the FLASH_OB_Unlock() function to unlock the Option Bytes. Disable the write protection using the FLASH_OB_DisableWRP() function. After that, use FLASH_OB_Launch() to apply the changes. Ensure Flash Erase is Done Remember that STM32 Flash memory must be erased before writing. Verify that you're correctly erasing the sector before attempting to write. Unlock Flash Memory If the Flash is locked, you can unlock it by writing a specific key to the Flash key register. This unlocks the memory for write operations: Use FLASH_Unlock() to unlock the Flash memory for writing. Check Power Supply Ensure that the STM32F103VDT6 is receiving a stable voltage. Flash programming can fail if the voltage supply dips below the required level. Consider measuring the power supply to verify this. Verify Peripheral Configuration Double-check that the clocks and other relevant peripherals are properly configured for Flash memory operations. For example: Make sure that the Flash memory access time is set correctly. Ensure that the system clock is set to an appropriate speed for Flash operations. Detailed Example Code for STM32F103VDT6 Flash Write

Here is an example of how to write to Flash memory, following the correct sequence:

#include "stm32f10x.h" void write_flash(uint32_t address, uint32_t data) { // Step 1: Unlock Flash FLASH_Unlock(); // Step 2: Erase the Flash sector (e.g., Sector 3) FLASH_EraseSector(FLASH_Sector_3, VoltageRange_3); // Step 3: Write the data to the Flash memory FLASH_ProgramWord(address, data); // Step 4: Lock Flash FLASH_Lock(); } int main(void) { // Example usage: Writing 0x12345678 to address 0x08020000 write_flash(0x08020000, 0x12345678); while (1) { } }

Conclusion

If you're facing issues with writing to the Flash memory on the STM32F103VDT6, make sure to follow the correct sequence for unlocking, erasing, and writing to the memory. Additionally, verify that the write protection is disabled, and ensure the voltage supply and peripheral settings are correct. By following these steps, you should be able to resolve most issues related to writing to Flash on this microcontroller.