They also do not have internal pull-up and pull-down resistors ( pinMode(36, INPUT_PULLUP) or pinMode(36, INPUT_PULLDOWN) cannot be used).

Pins GPIO36 (VP), GPIO39 (VN), GPIO34, and GPIO35 can only be used as input. Fortunately, there are other UART interfaces available. They can be useful for programming the board without a USB but with an external programmer instead.

If you use them, you will not be able to upload programs to the board or use the serial monitor via the USB port.

The GPIO1 (TX0) and GPIO3 (RX0) pins are used to communicate with the computer in UART via USB. In this case, the error appeared on a Linux when trying to upload code due to the drivers not being installed and the root permissions.For this reason, these pins are not available on uPesy ESP32 boards. language:bashĪvrdude: ser_open(): can't open device '/dev/ttyUSB0': No such file or directory You may receive an avrdude: ser_open(): can't open device error similar to the output shown below. If you installed the drivers for the CH340 on your computer but have issues connecting via serial terminal or uploading code using the Arduino IDE, there may be an issue with your user settings preventing you from using the CH340. COM Port Not Available Windows, Mac, and Linux Users seem to be able to eventually get the board recognized by a combination of giving the computer time to finish the install ( close to 20 min), plugging the board back in multiple times, reinstalling the drivers, and/or resetting the computer multiple times ( repeat both steps). Others have had issues where the installation process hangs.īased on the customer experiences, this might be specific to the manufacturer and are usually isolated cases. However, the board cannot be accessed on the Arduino IDE. We have had a few reports on Windows 10 where the driver will automatically install and the board will show up under a new COM port as USB-Serial CH340, but with a different device name. Troubleshooting COM Port is Not Showing Up as CH340 Windows

Wire library in arduino