CH9340K serial port

reason:

I saw that many open source projects are using the CH340K serial port chip, but this chip is not easy to buy, and it has now risen to 5RMB+ (CH9340K is less than 3RMB), and the cost of use is a bit high. I saw someone on the Internet saying that CH340K can be replaced by CH9340K, so I planned to apply this chip to the project I was preparing to produce. There is no application for CH9340K found online yet, so I made this board first for verification. By the way, it can be used as a serial port module, because the loading capacity of the serial port module I bought on Taobao is really poor.

Compared:

There are still differences between CH340K and CH9340K. Although the packages are both ESSOP-10, the functions and pins are different!

Comparison between Qinheng official website:

Pin comparison:

1.CH340K

2.CH9340K

3.CH340K data sheet

4. CH9340K data sheet

You can see that pins 0, 4, and 5 are not the same , and the functions of pins 0, 4, and 5 are different . Don’t believe the lies on the Internet that they can be directly replaced! ! !

Considering the actual application situation, I drew two different symbols and packages

One does not have pin 0 and the corresponding pad (CH9340K_Without_LOP#), and the other does (CH9340K)

Real object:

Device Manager identifies:

STC-ISP identification

About USB interface:

You can use USB-A or TYPE-C, so you don’t have to re-draw and print the board to use a different interface.

When using the TYPE-C port, I recommend using polyimide tape (commonly known as gold fingers) to cover the bottom and frame the four ports. After all, the TYPE-C female housing is made of metal. Who knows if there will be a short circuit?

Qinheng official website serial port driver download address (click to jump)