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STM32MP135F-DK OpenSTlinux USART1/USART2

AMend.7
Associate III

Hi,

When transmitting data to the ttySTM0 port, the data goes to the UART4_TX pin connected to the JTAG virtual serial input. However, I need an available TTL serial port to communicate with a microcontroller. How do I enable the USART1 port connected to the PC0/PB0 pins?
To which pins is the ttySTM3 port linked? How do I enable it?

 

root@stm32mp1:~# dmesg | grep tty
[ 0.000000] Kernel command line: root=PARTUUID=e91c4e10-16e6-4c0e-bd0e-77becf4a3582 rootwait rw console=ttySTM0,115200
[ 0.598790] 40010000.serial: ttySTM0 at MMIO 0x40010000 (irq = 61, base_baud = 4000000) is a stm32-usart
[ 3.619483] printk: console [ttySTM0] enabled
[ 4.294977] 4c001000.serial: ttySTM3 at MMIO 0x4c001000 (irq = 62, base_baud = 4000000) is a stm32-usart
[ 4.304256] serial serial0: tty port ttySTM3 registered
[ 11.426540] systemd[1]: Created slice Slice /system/getty.
[ 11.502583] systemd[1]: Created slice Slice /system/serial-getty.

1 ACCEPTED SOLUTION

Accepted Solutions

Hi @AMend.7 ,

 

You need to go to the file .../stm32mp-openstlinux-6.6-yocto-scarthgap-mpu-v25.06.11/sources/ostl-linux/linux-stm32mp-6.6.78-stm32mp-r2-r0

 

https://wiki.st.com/stm32mpu/wiki/STM32MPU_Developer_Package#Installing_the_OpenSTLinux_BSP_packages

In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.

View solution in original post

6 REPLIES 6
Gregory PLANCHON
ST Employee

Hi @AMend.7 ,

 

I think this wiki page can help you : 

https://wiki.st.com/stm32mpu/wiki/Serial_TTY_device_tree_configuration

 

Regards,

Grégory

In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.

Hi Gregory,

I was only able to install the source code (BSP) from the Developer package. Now I don't know what to do next:

Is it mandatory to use STM32CubeIDE to generate a new dts Device Tree file, or can I just edit the kit's original BSP dts file? If so, in which directory of the BSP source code is this dts file located?

After editing the dts file, can I compile this file separately, or do I need to recompile the entire Linux kernel?

Ari

Gregory PLANCHON
ST Employee

Hi @AMend.7 ,

 

You can find an explanation here about how to modify your device tree. You don't need to use the Cube IDE. You can edit the DT directly. 

 

Regards,

Grégory

In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.

Grégory,

  According to the link, the dts file is in the path: arch/arm/boot/dts/stm32mp135f-dk.dts but I can't find this path in the BSP source code installation on my computer: \Developer-Package\stm32mp-openstlinux-6.6-yocto-scarthgap-mpu-v25.08.27\sources\ostl-linux

 

Ari

Hi @AMend.7 ,

 

You need to go to the file .../stm32mp-openstlinux-6.6-yocto-scarthgap-mpu-v25.06.11/sources/ostl-linux/linux-stm32mp-6.6.78-stm32mp-r2-r0

 

https://wiki.st.com/stm32mpu/wiki/STM32MPU_Developer_Package#Installing_the_OpenSTLinux_BSP_packages

In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.

Grégory,

Thank you very much.
I found the file. I'll try following the steps in the link you sent me to test changing the LED's initial state before trying to add a new serial port to the kit's Linux image.

Ari