Arduino for STM32

This function is used to control CTS and RTS
But what I need is DE control which means that when the serial port sends data, the DE pin automatically changes to high level and then to low level after sending

IN STM32CUBEMX I found the serial port automatic flow control function:
https://img-blog.csdnimg.cn/img_convert/c48dc529e2604ca652a859fe6f075b4c.png

https://www.st.com/content/ccc/resource/technical/document/application_note/c8/5f/ef/b7/f8/a5/48/15/DM00055208.pdf/files/DM00055208.pdf/jcr:content ...

But my use of the following functions does not work:
digitalWrite(DE,HIGH);
Serial.println("hello");
digitalWrite(DE,LOW);


I have to do this by adding the DELAY function such as:
digitalWrite(DE,HIGH);
Serial.println("hello");
delay(10);
digitalWrite(DE,LOW);

Is there any way to automatically ...

When the TXD serial port is being sent, an I/O can automatically change to high level. When the TXD port is sent, it automatically changes to low level. In this way, you can control the sending and receiving of the RS485 chip

hardware flow control configuration APIs are available since 2.3.0:
https://github.com/stm32duino/Arduino_Core_STM32/pull/1634

However, the library file of version 2.3 only provides CTS and RTS control, which is often used for RS232 control. For RS485, there needs to be an IO to control whether ...

In industrial control, we often use 485,485 to receive or send depending on the 485 chip DE pin. Now whether you can add automatic flow control function in the code, to achieve 485 automatic manipulation 3 control. In the manual of STM32G070RBT6, I found these words: They provide hardware management ...