VL53L4CD_GUI intermittently fails to connect to NUCLEO-F401RE despite successful operation

[sawamura]

Hi,

 

Thank you for your support.

 

I was able to get VL53L4CD_GUI working using the firmware file:

VL53L4CD_PSNRun_F401.bin

 

However, the connection is very unstable and I am having difficulty using the GUI reliably.

 

Current status:

1. I programmed VL53L4CD_PSNRun_F401.bin into the NUCLEO-F401RE using STM32CubeProgrammer.

2. Initially, VL53L4CD_GUI could not connect.

3. I noticed that if I enable the option "Run after programming" in STM32CubeProgrammer during programming, VL53L4CD_GUI sometimes connects successfully.

4. When the connection succeeds, the GUI displays:

   Device Name : VL53L4CD
   API Version : api rev 0.2.2 build 3

   and I can acquire ranging data correctly.

5. However, after power cycling the board or reconnecting later, the GUI usually shows:

   "Failed To Connect to Nucleo Board: Com Port Not Detected"

6. In Windows Device Manager, the board is still visible as:

   "STMicroelectronics STLink Virtual COM Port"

   and the COM port is recognized correctly.

7. Reprogramming the same firmware file does not always restore communication.

8. Sometimes the GUI connects successfully, but most of the time it does not.

I cannot determine what condition allows the GUI to connect successfully.

Could you please advise:

- Is there a required startup sequence for the board and GUI?
- Should the firmware automatically start after a reset or power cycle?
- Is there any known issue with VL53L4CD_PSNRun_F401.bin on NUCLEO-F401RE?
- Is there any way to verify that the GUI firmware is running correctly after reset?

 

Thank you.

[John_Kvam]

When you program the eval kit you are downloading the program into the STM32 on the eval board. It is the job of the eval board software to take the commands from your PC and translate them into commands to the sensor. And once started, that STM32 code takes the range data (via I2C) and sends it back to the PC via the USB. 

But you don’t have to use the EVAL GUI on the PC. You can use TeraTerm - or any other terminal emulation software you like.

So use the GUI once to program the STM32, and issue the start command - then kill the GUI. 

Run TeraTerm and select the serial port. 

You are going to have to get the baud rate correct - and it’s a little tricky. But with the sensor running there will be a lot of traffic - so keep changing the baud rate until you get ranges - it’s all ASCII.

There are commands - stop start and help - but beware it’s NOT echo - so trust yourself and give it a try.

 

At the very minimum, you will figure out if it’s a GUI issue or a sensor issue. 

[sawamura]

Hi John,

Thank you for your reply.

 

I have already confirmed correct ranging operation using Tera Term.
Therefore, the sensor and STM32 firmware appear to be working correctly, and I suspect the issue is related to the VL53L4CD_GUI.

Could you please advise what could cause the VL53L4CD_GUI to fail to connect even though communication via Tera Term works correctly?

 

Best regards,

shigeki
 

[John_Kvam]

The GUI takes a long time to come up. So long in fact that a lot of people hit the icon again and start up two copies.

The first grabs onto the serial port and the second copy overlays exactly over the first and fails to connect because the serial port is already occupied. 

My other trick is to start the GUI while TeraTerm is still running - with the same result. 

But really the GUI doesn’t do much except to grab hold of the serial port and send and receive characters.

So if it doesn’t work - somehow the serial port is wrongly set - either busy, or the baud rate is wrong, or the wrong serial port is selected. 

(And nice job on checking with Tera Term. Not many people figure that one out.)