esp32 automatic downloader (CH340 USB to serial port)

1. Refer to Essence’s ESP32-S development board schematic diagram for production, see the attached ESP32-S manual.
2. The CH340G (external crystal oscillator) used in this schematic diagram is compatible with CH340C (built-in crystal oscillator). The physical verification uses CH340C.
You can also modify and use other chips in the CH340 series. According to the video introduction, there should be DTR and RTS pins for automatic downloading, as shown below:
3. 5V to 3.3V using LDO AMS1117 output should be connected to a tantalum capacitor (the reason is detailed See video). Tantalum capacitors are polarized capacitors. Like electrolytic capacitors, they will explode if the polarity is reversed.
However, the 3D packaging of Lichuang EDA Professional Edition seems to be reversed. I changed one but couldn't find the right one, so I gave up and tried to get the right one.
Save it as a personal library and adjust 3D to match the polarity correctly:
 
4. Welding suggestions:
(1) First solder the USB type C socket. Since it uses 16 pins, it is a little difficult to solder. After soldering, confirm that there is no solder connection. You can use a multimeter to test the phase. Whether adjacent pins are short-circuited. The four fixed legs of the seat must be welded firmly to prevent them from being knocked over when connecting the data cable, causing the solder pad to tear and make you want to cry without tears. After confirming that the Type C socket has no connection, plug in the USB to power on, and test 5V with a multimeter before proceeding to the next step.
(2) Solder AMS1117 and use a multimeter to confirm that the 3.3V output is correct.
(3) Solder other components.
(4) Confirm that there is no soldering or tin ball residue, and clean it with washing water.
5. Verification:
For the ESP32-S development board, use Arduino to burn the Zhuque soldering station program for testing. The program can be successfully uploaded after multiple burning tests.