CH9340 USB to serial port module

The mini version of the CH9340 USB to serial port module uses CH9340K as the conversion chip, without the need for an external crystal oscillator or driver.
The TYPE-C port is connected to the computer, and the 5-pin header leads to the +5V power supply, UART serial port (RXD/TXD), and ground (GND). The wiring sequence is as follows:
onboard RX/TX indicator light. When sending data, the red LED flashes; receiving When data is being read, the green LED flashes
onboard 0.5A self-recovery insurance. The original design used an ESD array as electrostatic protection, but it was removed from the PCB due to size restrictions: (
The PCB size is 14mm*22mm, which is better than the online solution using this chip. It should be smaller.
Because this chip uses the system’s own CDC driver, many functions cannot be used normally, but it is no problem to download the program to the microcontroller. If necessary, it is recommended to change to CH340K, VCP driver (only 4 and 5 pins). Definitions are different)
PCB size diagram:
Physical picture (there are no curved pins on hand, use straight ones instead)
Connect to the computer and send data:
When sending data, the TX light flashes.
Use STC-ISP to download a program to 89C52, and disconnect the target microcontroller first. After powering on, the pups will be born normally.