USB pass through

[jwinfieldnz]

I have hijacked the serial off my CH4300 (Ender 3 V2). This removes the function of the front USB port now. Is it possible to use the USB of the ESP32 to pass the data through to the serial to return the USB function? Maybe I am using the wrong UART of the ESP32, I am using the default config.

[luc-github]

you mean connect Printer usb to ESP32 USB ?

[luc-github]

I am not electronician - but I do not think so

[jwinfieldnz]

Right now it can collect serial data from port 8888 and pass this onto serial a serial port. It would be good to be able to receive serial data from the USB and also pass this to the serial port. For example https://docs.arduino.cc/built-in-examples/communication/SerialPassthrough

[luc-github]

Yes it should not be hard to add this, but is was not a priority as there was no user case for it, I am lazy guy ,I do not do things if there is not need for them.
what would be the purpose of such bridge ?

[jwinfieldnz]

I love your honesty. I added this to my machine. If I have to swap over to the built-in USB it'll be a major to pull it all apart. Having a USB pass-through I lose nothing, without it I lose USB. I made a video using your software here: https://youtu.be/chc8zRZh18A and am doing a hackaday.io article. It would be good to be able to say all benefits, not losses.

[luc-github]

Ok I see - your printer has only one serial then,

I know it is not what you expect but in short term would using this command to disable the Serial of ESP3D may help

* Get state / Set Enable / Disable Serial Communication
[ESP900]<ENABLE/DISABLE>

The bridge could be definitly implemented, but will be in 3.0 which should allow this addon pretty easily
You may have a look to it : https://github.com/luc-github/ESP3D/tree/3.0
3.0 come with lot of new features compare to 2.x
https://github.com/luc-github/ESP3D/blob/3.0/Features.md
https://github.com/luc-github/ESP3D-WEBUI/blob/3.0/Features.md

[luc-github]

I have created a feature request :#800

[luc-github]

again USB host otg and usb host for printer usb are different
That said if you can have working solution I would be happy to test it

[luc-github]

@liqijian101 as confirmation espressif/arduino-esp32#7176 USB host is not supported in this way

[jwinfieldnz]

The function he wanted was,
The ESP32 uses USB to connect to the USB of the printer's motherboard, which is connected to the CH340.

Not correct. I have connected directly to CH340 so am bypassing the printer USB. If this feature allows me to connect to the printer to replace CH340 this solution is ideal. I have not had a chance to test it yet.

[jwinfieldnz]

Looking at configuration.h

* which serial ESP use to communicate to printer (ESP32 has 3 serials available, ESP8266 only 2)
* USE_SERIAL_0 //for ESP8266/32, also used by bootloader output, so consider to make it quiet
* USE_SERIAL_1 //for ESP8266/32
* USE_SERIAL_2 //for ESP32 Only
*/
//Main serial port
#define ESP_SERIAL_OUTPUT USE_SERIAL_0

/* Bridge Serial port (deprecated on esp8266 as second serial is)
* which serial ESP use to bridge to another device (ESP32 has 3 serials available, ESP8266 only 2)
* USE_SERIAL_0 //for ESP8266/32, also used by bootloader output, so consider to make it quiet
* USE_SERIAL_1 //for ESP8266/32
* USE_SERIAL_2 //for ESP32 Only\
* Comment if not used
*/

Would it work if the bridge port and main serial are the same?

[luc-github]

no you will get error message telling you it is not possible