Zephyr: how DAC on STM32H723ZG ?

[Lysandros]

Dear all,
does anyone have experience with setting analog output signals via Zephyr RTOS? I managed to get the D/A conversion on the Nucleo H723ZG to run via STM32CubeIDE, but I’m running intro trouble when using Zephyr. Apparently a "DAC" driver is required, however the documentation is not very clear.

Thanks 

[AScha.3]

Hi,

>running intro trouble when using Zephyr

Why ? Using RTOS or not - you just write to the DAC , no "driver" needed.

When using Cube/HAL , to setup the chip configuration, just use the HAL functions or write direct to DAC .

[Sarra.S]

Hello @Lysandros, 

You can use STM32H743 as a reference as the Nucleo H723ZG is not yet supported in Zephyr.

You'll need to create a new board definition under zephyr/boards/arm/, in which you add the board config (board.dts, board_defconfig, Kconfig.board , andCMakeLists.txt) 

There is already a sample of DAC with STM32H743.overlay here

This is not a simple task, but it is worth it if you're willing to invest some time learning the whole Zephyr architecture

[Lysandros]

Hello @Sarra.S ,

thanks for your reply and this hyperlink.

I have a few follow-up questions:

• I am surprised that "Nucleo H723ZG is not yet supported in Zephyr", because other applications and some samples actually run on this very board with Zephyr. On the other hand, I get: #error "Unsupported board: see README and check /zephyr,user node" when I try to run the dac sample with the H723ZG...
• the directory zephyr/boards/arm/ contains folders for the V2M, MPS2 and MPS3 boards. However the directory zephyr/boards/st/ actually contains many Nucleo boards including the H743ZI and H723ZG, listing the files you mention (except the CMakeLists.txt). What is the difference between the directories zephyr/boards/arm/ and zephyr/boards/st/ then?
•  I'm getting the error "No SOURCES given to Zephyr library: drivers__dac". Could it be, that I have to target this driver library somewhere?
• Can you recommend training courses on Zephyr, in particular for ST boads?

Best regards

Lysandros

[Sarra.S · Accepted solution]

Hello Lysandros, 

Sorry for the confusion! the STM32H723 is supported: Zephyr supported boards 

• zephyr/boards/arm/: This directory contains board configuration files for ARM architecture-based boards such as V2M, MPS2, and MPS3, which are ARM Versatile Express boards.

• zephyr/boards/st/: This directory is specifically for ST boards. The naming convention here is more vendor-specific, focusing on ST's product lines like the Nucleo series, which includes models such as H743ZI and H723ZG.

"No SOURCES given to Zephyr library: drivers__dac": this could happen if the CMakeLists.txt file for the DAC driver is missing the necessary source files

Regarding trainings, this is all I can think about: 

GitHub - zephyrproject-rtos/hal_stm32

https://docs.zephyrproject.org/latest/ 

https://discord.com/invite/Ck7jw53nU2 

You can check PR issues here: https://github.com/zephyrproject-rtos/zephyr/labels/platform%3A%20STM32 

Use STM32Cube in your application: https://github.com/zephyrproject-rtos/hal_stm32#use-stm32cube-in-your-application

Hope that helps!