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Grant Bt
Grant Bt
Associate III
May 13, 2026
Solved

RDP Value shown only as a checkbox. Is this normal?

  • May 13, 2026
  • 3 replies
  • 200 views

I'm looking at setting the RDP Level to Level 1 for an STM32F103 and I don't see the AA BB CC type stuff like in the current manual. Is this something that STM32CubeProgrammer is doing on purpose for this MCU?  I definitely don't want to enable Level 2 by accident and brick my chip.  Here is a screenshot of what I see:

CubeProgrammer RDP Checkbox.jpgIs it safe to check this?

 

Best answer by mƎALLEm

Hello,

In STM32F10xx (first STM32 series), the flash protection was simple. No RDP levels 0, 1 and 2. Only RDP activated / RDP not activated.

Please refer to PM0075.

mALLEm_0-1778749949672.png

mALLEm_1-1778749972754.png

So yes you can check it to protect the flash from reading.

3 replies

mƎALLEm
mƎALLEmAnswer
Technical Moderator
May 14, 2026

Hello,

In STM32F10xx (first STM32 series), the flash protection was simple. No RDP levels 0, 1 and 2. Only RDP activated / RDP not activated.

Please refer to PM0075.

mALLEm_0-1778749949672.png

mALLEm_1-1778749972754.png

So yes you can check it to protect the flash from reading.

To give better visibility on the answered topics, please click "Best answer" on the reply which solved your issue or answered your question.
    Grant Bt
    Grant BtAuthor
    Associate III
    May 14, 2026

    Thanks for the reminder to check the data sheet (and doing so on my behalf). The internet is a dogs breakfast. Even here, simply skimming topics can be, um, insufficient.

     

    Introduction

    STM32F1 microcontrollers offer three levels of read-out protection: level 0 (no protection), level 1 (Flash memory, backup SRAM, and backup registers protected), and level 2 (same as level 1, but with permanent protection by locking the option bytes). It's important to note that level 2 should only be considered for the final product, not during development stages.

     

    https://community.st.com/t5/stm32-mcus/how-to-change-the-read-out-protection-on-stm32f1/ta-p/49408

     

      mƎALLEm
      mƎALLEm
      Technical Moderator
      May 14, 2026

      Hello @Grant Bt ,

      Thanks for sharing.

      I need to check with the knowledge base article owner.

      To me STM32F10x has only two levels Level 0: no read protection, Level 1: read out protection enabled. (unless I'm missing something).

      Even in the driver (stm32f1xx_hal_flash_ex.h), two levels are available:

      /** @defgroup FLASHEx_OB_Read_Protection Option Byte Read Protection
 * @{
 */
#define OB_RDP_LEVEL_0 ((uint8_t)0xA5)
#define OB_RDP_LEVEL_1 ((uint8_t)0x00)
      To give better visibility on the answered topics, please click "Best answer" on the reply which solved your issue or answered your question.
        Grant Bt
        Grant BtAuthor
        Associate III
        May 14, 2026

        Thank you!

        mƎALLEm
        mƎALLEm
        Technical Moderator
        May 15, 2026

        @Grant Bt 

        The article has been updated and mentioned that there is no RDP L2 on STM32F103.

        Thank you for your contribution.

        To give better visibility on the answered topics, please click "Best answer" on the reply which solved your issue or answered your question.
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