ESP32 UART-USB Brige How to use

Post by **stefan.erni** » Fri Aug 22, 2025 9:27 am

Hi to All

I use a Atom S3 with a display. It's working nice with an extern AD converter and shows the values on display.
But I can not send the values to the App-developper
I found a help in the internet, there is an intern UART-USB Brige.
How can I use it?

Select UART0.
Enter the default pins of the ESP32-S3:
TX → GPIO43
RX → GPIO44
Even if you do not wire the pins, Flowcode will know which UART it refers to, and the output will be correctly transmitted to the PC via the USB-CDC port

Uart port:

: 2025-08-22_10-18-51.PNG (53.85 KiB) Viewed 280 times

Testprogram:

Post-ESP32_S3_Display2_MCP.fcfx: (64.11 KiB) Downloaded 15 times

Post by **medelec35** » Fri Aug 22, 2025 10:37 am

Hi Stefan.
Have you looked at all the PC developer projects here.
There are projects that use USB for communicating between hardware and PC developer using USB

Post by **stefan.erni** » Fri Aug 22, 2025 11:31 am

Hi Martin

Yes, right now again. If the board has a UART to USB bridge (for example, CH340C), it works very well.
I have already done many projects with it, and that work very well with the Appdevelopper.

Now the problem:
Many new supermini boards with ESP32-C3, ESP32-C6, ESP32-S3 no longer have an additional IC (UART-USB bridge) on the board.
However, Flowcode does not yet support a direct USB connection for the ESP32.

There is another option for the small ESP-S3 chip.
The ESP32 S3, which has a UART-USB bridge integrated into the chip, as I understand it.
It can be used with uart0 and set TX/RX on GPIO 43 and GPIO 44.

I just don't know exactly how that works with Flowcode.

Post by **stefan.erni** » Wed Aug 27, 2025 9:42 am

Hi Martin

I am not yet able to establish a connection between the ESP32-S3 and the PC.
However, I have more information on this.

https://github.com/espressif/esp-usb-bridge

Post by **mnfisher** » Wed Aug 27, 2025 10:15 am

I'll have a look- it should be possible using the OTG USB interface...

Martin

Post by **mnfisher** » Wed Aug 27, 2025 10:22 pm

Hi Stefan,

Can you try this - run idf.py menuconfig
component config - esp system settings - channel for console output -> Set this to USBSerial/JTAG Controller

NB - target must be set as an esp32s3 (idf.py set-target esp32s3)

Check if usual debug is then sent to USB (using PuTTY for exanple)

Then try using a UART on Pins 19 and 20

I don't have an s3 to test

Martin

Post by **stefan.erni** » Thu Aug 28, 2025 11:37 am

Hi Martin

I understand there are two ways to use USB: as very fast USB OTG and with the built-in bridge.
I have tried both, but without success.

I'll take a closer look at it.
The ESP32 S3 can be easily programmed with Flowcode.
I will use the small, inexpensive Seed and the Atom S3 display.
I have made a list of various manufacturers if you want an S3.
There are many other ESP32 S3 modules that are very practical.

Seed: