DFU mode read out protection

[Draxter]

Hello, 

I am trying to connect to the STM32F072C8T6 microcontroller via USB in the STM32CubeProgrammer, however I am getting:

"Device is under read out protection ! If you want to disable RDP please reconnect with Read Unprotect enabled"

So, when I check the Read Unprotect (MCU) checkbox, I get:

"Please Power off Power on your device."

After turning the power off/on, I see the same messages. I cannot connect to the MCU via USB in the STM32CubeProgrammer.

I have tried different versions of STM32CubeProgrammer:

• v2.16.0
• v2.15.0
• v.2.13.0
• v.2.10.0
• v.2.8.0

Moreover I tried on second computer with Windows 11 and I have the same issue.

I'm trying to connect my custom board, but I also checked another hardware board (BluePill ) with the same STM32F072C8T6 MCU and it doesn't work either.

Interestingly, using the DFU-util v0.8 program I can connect to the MCU and successfully read/write memory:

[Amine_Jridi · Accepted solution]

Hello @Draxter 

Regarding this issue, we are aware of it and it's currently under investigation.

Internal ticket number: 171192 (This is an internal tracking number and is not accessible or usable by customers).

As a workaround, we suggest connecting your MCU using a HUB instead of plugging it directly into the PC.

Thanks,

Amine.

[Draxter]

@Amine_Jridi thank you. Connecting the board to an external USB HUB solves the problem.

We are unable to understand what is root cause. Why use a USB HUB instead of a direct connection to a computer?

[new_earth75]

Hello Amine,

Is there any progress on this issue?

I'm using v2.17.0 and I have the same symptoms on my DELL when I plug STM32F0 board on the laptops USB-C ports.

If I use a USB C to A cable on my USB hub, it works. If I use a USB C to A plug converter, then its the same as using a USB C cable.

BR

[Draxter]

@new_earth75 answer from STMicroelectronics support:

In fact, the issue is coming from the USB bootloader state machine which hangs and stuck in busy state.

This issue is seen only on recent machines with high speed USB controllers, and putting a hub resolves the issue.

Other possible solutions :

- Using dfuse

- Using connectors downgrading the USB speed then putting some more latency in the transmission to make it work

[NeoPete]

Hello,

We also are very interested in the progress in this matter, since we experience the exact same thing. Our hardware though is using the STM32L552. 

[NeoPete]

...I can also add that we've been doing tests on

• Win 10
• Win 11
• Ubuntu

We get the same problem in all 3 environments when connecting the device directly to the computer, but can conclude that in Linux things works much better compared to Windows, but eventually also fails and reboots there. In Windows the problem occurs only on a random set of computers, and most of them are using Win 10, but it does happen on some Win 11 computers as well. On our Linux machines the errors happen more rarely, but they do occur every now and then. 

All in all we get rid of the problem when using a USB-Hub in between the device and the computer. 

[new_earth75]

Yes its quite common on newer machines. The machines that are affected on our side are the ones that support Thunderbold or USB4. I guess the fact that the USB is handled directly by the CPU rather than some chipset with integrated USB hub is the issue.

I asked about this issue in the v2.17.0 release thread but of course there is no answer. The dont aknowledge this in the known issues part of the patch notes either.

I dont care that a USB 2.0 hub solves the issue! Honestly I find distressing that the timings in ST's software rely on the USB controllers latency to work. Man we've got production lines to build and we get this to work with... What's next? Will we need a PS/2 mouse to click on the buttons and a parallel port to remove Write Protection?

My newer machines use dfuse and it seems to work well.

Good luck with yours.

AT