UART output missing characters in XCTU terminal (STM32 + VL53L0X)

[27_it]

I am working with an STM32 microcontroller and a VL53L0X sensor. The sensor readings are transmitted over UART1 at 115200 baud, 8N1.

I have verified:

• UART initialized at 115200 baud, 8N1, no parity

• XCTU terminal set to ASCII mode (Hide Hex enabled)

• Line endings set to \r\n

Any suggestions for reliable output?

Numeric values are printed correctly, but the text parts like "Distance" and "mm" are missing or appear as dots in XCTU’s terminal. For example, instead of:

Code

Distance: 25 mm

I see:

Code

D..ta..e: 25 mm

[Andrew Neil]

Welcome to the forum

Please see How to write your question to maximize your chances to find a solution for best results.

In particular, what STM32 and what board are you using ?

 

XCTU terminal

Never head of that one - do you mean this: https://www.digi.com/support/knowledge-base/x-ctu-xctu-software ?

 

missing or appear as dots in XCTU’s terminal.

Maybe this is how it shows reception errors?

Commonest reason for that is wrong baud rate.

For reliable baud rates, avoid using internal RC oscillators.

Have you used an oscilloscope to check what the UART is actually sending?

 

Before adding the VL53L0X, have you got a basic UART “Hello world” working ?

[27_it]

​@Andrew Neil Thanks for responding! Hello world also shows missing characters and  dots,  baud rate at both ends are equal and am using HSE clock source only . Yes  https://www.digi.com/support/knowledge-base/x-ctu-xctu-software it is this software only 

[Andrew Neil]

baud rate at both ends are equal  

You mean your settings are the same ?

But how have you proved that you are actually getting the baud rate that you think you configured?

Again, Have you used an oscilloscope to check what the UART is actually sending?

A continuous stream of uppercase ‘U’ is good for checking baud rate on a scope …

 

Have you tried using a “standard” terminal; eg, TeraTerm?

Maybe this Digi utility has some “quirks”, or places some special interpretations on your data.

The description at that link doesn’t really suggest that it’s intended as a general-purpose terminal

[Gyessine]

hello ​@27_it 
as ​​​​@Andrew Neil  you need to provide more details so that support can identify the root cause of the issue.

To start troubleshooting, create a simple UART project that transmits "Hello world" in a known serial monitor.

If STM32CubeMX is used to create the project, ensure that the input clock frequency matches the actual frequency in use, especially if HSE is the clock source in.
BR
Gyessine