ESP32-development board (TYPE-C CH340C)

Major circuit modifications:

1. Replace the CH340E used in the original design with the cheaper CH340C to solve the problem of automatic download failure caused by the lack of DTR signal in CH340E;

2. To ensure the stability of the automatic download function, a 10uF capacitor is connected in parallel to the EN switch;

(For specific principles, please refer to https://zhuanlan.zhihu.com/p/145369083?from_voters_page=true and https://blog.csdn.net/weixin_41975300/article/details/104834771 )

3. The front and back sides of the development board are marked with pins for easy use;

4. On September 17, 2021, CC1 and CC2 were added to ground with a 5.1K resistor to support CC line power supply (PD standard power supply), which is available for testing;

5. On September 17, 2021, serial port RXD and TXD signal indicators were added. The indicators flash during serial port data communication, which is cool;

6. The LDO is AMS1117. Choose two packages (SOT89, SOT223) to design two versions. The former has a more beautiful layout, while the latter has a more common package and a large power supply current. Each has its own advantages;