ST-Link V3 bug? large UART strings with fast baud rate fails (lost characters)

[Torsten Jaekel]

We use NUCLEO-H743ZI (old) and NUCLEO-H743ZI2 boards. The difference: ST-Link V2 vs. ST-Link V3.

The same FW fails on newer ZI2 board with the ST-LINK V3 for the USB VCP UART transfer.

Issue:

I send files from terminal, or I use copy and paste of large strings in UART command line. It works fine on old ZI board (ST-LINK V2) but it fails on new ZI2 with ST-LINK V3.

Even ST-Link V3 seems to work up to 10,000,000 bauds, if I use 1,8432,000 and I send large strings (from file or copy and paste in command line) which are larger as 255 characters - I lose many or even all characters.

ST-Link V3 seems to have an issue with internal UART buffer management:

• I send a very large string - it depends how large: just the first few characters are received and forwarded to main MCU, or just the tail of the string
• I did a test: if I send exactly 256 characters - the main MCU does not get any character!

So, it looks to me:

when sending with fast baud rate, seamlessly a large string, above 255 bytes the internal UART buffer management (e,g. a buffer index) rolls over and all first characters are lost.

ST-Link V3 cannot keep up with large fast data (strings) coming in: it loses the entire string if 256 characters long (nothing forwarded to main MCU UART) or you lose characters if larger.

All works fine with same main MCU FW, drivers etc. It seems to be related to the ST-Link V3 chip and firmware.

==> I would need an urgent bug fix for it, because we use the UART from Python scripts for tests of external hardware. The new only available NUCLEO-H743ZI2 board does not work right now due to it.

Dear STM team: please could you have a look in to issue to send large strings with fast baud rates via ST-Link V3 USB VCP UART.

Thank you.

[S C · Accepted solution]

Hello,

This is a known issue which was fixed in version V3J3M2 (january 2019). Now the most recent version available is V3J5M2, please update the STLINK-V3SET firmware:

https://www.st.com/en/development-tools/stsw-link007.html. If an issue persists with this ST-Link firmware version, please precise on which host operating system it occurs (it might also involve the USB communication between host and ST-Link)

Best regards

[Torsten Jaekel]

Thank you. After updating the ST-Link V3 firmware - it works now. Great.

My FW on boards delivered was: V3.J4.M1. New is now V3.J5.M2 .

[Ricky Gai]

I totally cannot establish link with STLINK V3 as picture attached, just bought this ST-LINK V3SET few days ago, going to return it back in replace a new unit.

[S C]

Hello,

Please try to run STLinkUpgrade application out of any other application context:

• either running from <STM32CubeProgrammer location>/Drivers/FirmwareUpgrade/. Typically on Windows <STM32CubeProgrammer location> = C:/Program Files/STMicroelectronics/STM32Cube/
• or get it from STSW-LINK007 - ST-LINK, ST-LINK/V2, ST-LINK/V2-1, STLINK-V3 boards firmware upgrade - STMicroelectronics (will be more recent: 3.3.5 instead of 3.3.4)
• do a power cycle of the STLink board and close all applications which might have opened a connection to it
• Run STLinkUpgrade

[Ricky Gai]

hi S C,

I found the issues, the ST-LINK V3SET cannot be identified under USB HUB but when I connected directly to standalone USB port it works and upgraded its firmware to latest version as I documented this morning on the thread below:

https://community.st.com/s/question/0D73W000000mz7O/detail?s1oid=00Db0000000YtG6&t=1613993186092&s1nid=0DB0X000000DYbd&emkind=chatterCommentNotification&s1uid=0053W000001o8WP&emtm=1613957158921&fromEmail=1&s1ext=0

1. Why ST-LINK V3SET cannot work with USB HUB ?
2. Can ST-LINK V3SET works with clone board STM32F103C8T6 ? as I am having issues connecting it successfully via STM32CubeProgrammer as mentioned on the thread link above, please have a look.

Please advise.

Thank you.

[S C]

Hello,

1. Please ensure your hub supports USB High Speed, because the STLINK-V3SET does not support the Full Speed mode. That's the first reason I can imagine. There is no specific driver for STLINK-V3 on Windows, it relies on WinUSB (= Windows native) for debug and bridge interfaces, standard mass storage and Virtual COM port drivers.
2. What are you calling "clone board STM32F103C8T6" ? If it is made with a genuine STM32 you should have no issue: check the power, the JTAG/SWD connection, the target reset and try different connection modes. Otherwise I have no idea and no way to check

[Ricky Gai]

hi,

1. Is just normal USB 2.0, if you mentioned USB high speed, does it means USB 3.0 ?
2. Well, the clone board STM32F103C8T6 I referred is none ST official development boards ( eg. Nucleo ) where normally is white color PCB.
3. I have described all I knew and documented under this THREAD, can you click on it and have a look ?
4. The problem is, I cannot find a complete setup diagram through the internet, I am not building a rocket project, is just to connect to the STM32F103C8T6 board with ST-LINK V3SET, but taken two days also cannot be resolved, even since received ST-LINK V3SET 3 days ago. I am new to ST and that's why asking lots of stupid questions.

[S C]

Hello,

High Speed means USB 2.0, however USB 2.0 still supports Full Speed devices. High Speed is 480Mbps while Full Speed is 12Mbps.

My understanding is that the board does not contain a STM32F103 from ST, which most probably explains why you can't connect with the STLINK-V3. Moreover they rather recommend J-Link. Depending on your needs, perhaps should you buy a Nucleo (or discovery board) rather than this board+STLINK-V3SET because ST Nucleo/disco boards contain simultaneously the probe (embedded ST-Link) and a target device (which you can choose among the whole ST portfolio). If you want to keep this board, I'm afraid you will need to buy another tool

[Ricky Gai]

hi S C,

Thanks for the feedback, I used ST-LINK V2 able to connect three STM32F103C8T6 clone boards successfully shown below:

I already ordered NUCLEO-F103RB last week, as there is no stock available, I need to wait until March 2021.

I can accept the said of none genuine STM32F103 used here, because two of them are labelled CKS32F103C8T6 and remaining is labelled with ST logo but all three can be connected via ST-LINK V2 but not ST-LINK V3SET.

Well, since STMicroelectronics mentioned on its product website that ST-LINK V3SET support STM32 MCUs it seems there are more stories behind though which I really have to return this product.

Thank you.