A possibility that ch340 module cannot be recognized / burned

     use CH340 Chip program burning , Encountered cannot burn / The problem of identification .
    
     Of course, there are many reasons why it can't be written , It depends on the type of food you serve , If you want to cook , You can refer to CH340 The manufacturer of Datasheet, There are ready-made circuit connections ; If you design circuit board dishes , It may be the problem of circuit board design ; If you weld vegetables , Maybe the welding is broken .
    
    CH340 There are many types , It's very traditional CH340G, And CH340G The crystal free version in the same package CH340C, Of course, I'm lazy , Yes CH340C, And there's just 8 Foot's CH340N, I don't know if it's easy to use .
    
    CH340C One pin is V3, To receive 104 capacitance , I was anxious when I made the board , Weld well CH340 Connect to the computer to see if it works , Of course, it doesn't show , As a result, the procedure cannot be burned after all welding , But the strange thing is that it can be PC distinguish , It can also erase programs .
    
     I thought for a long time. , I think it may be because the capacitor is not connected , So a new plate was welded , Power on after welding everything this time , Sure enough, you can burn it this time .
    
     summary ： Be sure to weld all capacitors before power on , Otherwise, it is easy to burn chips .