preface

I don't know why, the USB to serial port on the market would rather lead out the rarely used RTS pin than lead out the DTR pin.

The CH340G/CH340C chip clearly has this pin. Connect a 0.1uF capacitor on the DTR pin to the RST pin of ATmegaX to realize the automatic download of the Arudino system (if a board like Pro Mini is connected directly to the DTR pin, the development board has its own required capacitor), but the serial port module on Taobao basically does not use this pin.

The most ridiculous thing is that they are basically USB A ports. I wonder whether their USB HUB has several meters of cable or something. Every time, I have to connect a long strip of DuPont cable to the development board. In order to meet my own needs, I simply make a USB serial port.

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