Controlling Nucleo LEDS via UART

Here is an attempt to control user LEDs from PC using UART from STM NUCLEO-F767ZI development board.

Please read my Getting started with ST NUCLEO F767ZI Board for development setup instructions.

Following commands are implemented (from help):

help      - to show this help
led1 on   - to turn green LED LD1 on
led1 off  - to turn green LED LD1 off
led2 on   - to turn blue  LED LD2 on
led2 off  - to turn blue  LED LD2 off

Source tree

The UART_Printf/ is versioned as overlay (only changed files there) of target directory:

STM32Cube_FW_F7_V1.14.0\Projects\STM32F767ZI-Nucleo\Examples\UART\UART_Printf\ 

For development you need to download and extract en.stm32cubef7.zip from STM32CubeF7:

Accessing UART from Windows

At first you need to know correct serial port name - COMx (where x is some number).

To get it:

• open Device Manager (for example running devmgmt.msc)
• Expand Ports (COM & LPT)
• There should be entry like STMicroelectronics STLink Virtual COM Port COM5

In my case name of UART (serial port) is COM5.

Now we need some program to access UART. There is mentioned Hyperterminal in original ST docs but it is no longer included in Windows.

However we can use Putty for this purpose.

To configure Putty for UART access:

• run Putty
• enter suitable name into "Saved Sessions:" for example STM32-9600-7bit-odd
• select "Connection type:" Serial
• on Category tree expand Connection -> Serial
• ensure that following values are configured:
  • "Serial line connect to": your COM port name, for example COM5
  • "Speed (baud):" 9600
  • "Data bits:" 7
  • "Stop bits:" 1
  • "Parity:" Odd
  • "Flow Control:" None
• click back on Session in "Category:" tree
• click on Save

Now you can just double-click on session name STM32-9600-7bit-odd to open connection to UART (serial port).

If you try original STM32F767ZI-Nucleo\Examples\UART\UART_Printf\ example from STM you should see after each reset on Nucleo board text like:

 UART Printf Example: retarget the C library printf function to the UART
** Test finished successfully. **

Known bugs/limitations

• Command editing (arrows, delete, backspace) does not work and produce confusing results...