Firmware doesn't work when Read Out Protection is enabled.

[HJung.2]

I programmed stm32F103RCT6 firmware using STM32CubeIDE.

When Read Out Protection (RDP) is disabled, the firmware works well.

But RDP is enabled, the firmware doesn't work.

My firmware is transmitting data by UART.

when RDP is disabled, Firmware sends data like the pic below

However, RDP is enabled. I cannot see anything.

How can the firmware work when RDP is enabled?

I'm using QFP 64pin socket & connected Jtag by ST-Link v2.

[Mike_ST]

Please try to unplug the JTAG connector when RDP is enabled, power cycle and check whether your firmware works.

[HJung.2]

Hello! Thank you for your answer!

I use JTAG for debugging and reset the chip.

I tried to reset and start the firmware without jtag, but socket doesn't have reset button like NUCLEO board.

So I couldn't reset the chip without jtag.

Is there any solution for start firmware without jtag??

And for further work, I must use JTAG.

Does the firmware never work with JTAG when RDP is enabled?

[Mike_ST]

>> Is there any solution for start firmware without jtag??

Yes, power off then power on.

I see on the picture that you are using a breakout board, find the RESET pin and pull it to ground for a short time.

>> Does the firmware never work with JTAG when RDP is enabled?

This is read-out protection, by definition it forbids access to the flash. If you plug debug probe, the mcu will forbid access.

Probably entering a locked state.

[HJung.2]

Thank you for your answer!

Reset works well when the RESET pin is pulled to ground!

Thanks!!!

I have the last question left.

I unplugged JTAG and reset the MCU which RDP enabled and then the firmware doesn't work.

Do you mean that when RDP(Read Out Protection) is enabled, the user firmware in flash doesn't work regardless of plugging JTAG?

[HJung.2]

Thank you for your answer!

Reset works well when the RESET pin is pulled to ground!

Thanks!!!

I have the last question left.

I unplugged JTAG and reset the MCU which RDP enabled and then the firmware doesn't work.

Do you mean that when RDP(Read Out Protection) is enabled, the user firmware in flash doesn't work regardless of plugging JTAG?

[Mike_ST · Accepted solution]

If JTAG is unplugged, and RDP enabled, your software should work...

Please check that the BOOT0 pin is correctly pulled to ground.