Circuit board ch340g computer cannot recognize USB device?

xbxdbd

Circuit board ch340g computer cannot recognize USB device? [Copy link]

 

After soldering the device, when burning the program, the computer shows that it cannot recognize the USB device. The voltage of 5v and 3.3v are normal. One end of the crystal oscillator is 5.11v and the other end is 5.08v. I changed all the components of the serial port, but it cannot be recognized. The last time I changed ch340g again, the computer recognized the serial port. I plugged and unplugged it again, but the computer still could not recognize the USB device. What is the reason?

秦天qintian0303

Has the USB socket been replaced?

tagetage

You should use a USB cable of better quality and shorter size, and plug it into the port on the computer motherboard. Do not plug it into the USB port on the front of the desktop computer. Then try it again.

wangerxian

Have you installed the CH340 driver?

xbxdbd

wangerxian posted on 2024-3-12 18:09 Have you installed the driver for CH340?

Installed

xbxdbd

Qintianqintian0303 posted on 2024-3-12 15:40 Have you changed the USB socket?

problem solved

xbxdbd

Qintianqintian0303 posted on 2024-3-12 15:40 Have you changed the USB socket?

I made the ch340g module into two USB male connectors according to what you know before, and then I have a serial port number, but I still can't download the program. I also changed the crystal oscillator but it didn't work.

This is the serial port part of a board

The real thing is like this

What is the reason?

xbxdbd

Qintianqintian0303 posted on 2024-3-12 15:40 Have you changed the USB socket?

Also, when I use this ch340g module to connect the circuit board, this light will light up. Logically speaking, this light should not be on.

Is the main control chip broken?

xbxdbd

xbxdbd posted on 2024-3-12 18:58 Also, I use this ch340g module to connect the circuit board, and this light will light up. Logically speaking, this light should not be on. Is it...

Is it because my boot0 is not set to 1, which causes the program to fail to download?

damiaa

xbxdbd posted on 2024-3-13 08:38 Is it because my boot0 is not set to 1 that the program cannot be downloaded?

When burning stm32, boot0 is pulled high or low by external input. The microcontroller can't control it. ch340G can control it.

If you can't find the USB, start with ch340G.

Check the reset of the microcontroller. If the reset is not correct, it will not work.

Serial communication is tx === rx

rx === tx seems to be ok here.

You can check whether the crystal is oscillating, which can also indirectly determine whether the microcontroller can work.

xbxdbd

damiaa posted on 2024-3-13 09:01 When burning stm32, boot0 is pulled high and low by external input. The microcontroller can't control it. ch340G controls it. If you can't find the USB, ...

Flymcu can find the serial port number, but cannot download the program. The chip times out and responds, and the program cannot be downloaded.

damiaa

xbxdbd posted on 2024-3-13 09:16 FlyMCU can find the serial port number, but cannot download the program. The chip times out and responds, and the program cannot be downloaded.

Is the boot0 of your microcontroller directly connected to ground?

Pull up the boot0. Disconnect the pull-down first. Restore it when running the program after burning.

xbxdbd

damiaa posted on 2024-3-13 09:23 Is the boot0 of your microcontroller directly connected to the ground? Pull up the boot0. Disconnect the pull-down first. After burning, run the program...

Now my circuit board boot0 is directly grounded. Do I need to cut the wire and jumper it to high level? Another phenomenon is that when I connect to the computer to download the program, the LED indicator light is always on, which should not be on.

damiaa

xbxdbd posted on 2024-3-13 09:36 Now my circuit board boot0 is directly grounded. Do I need to cut the wire and jumper it to high level? Another phenomenon is that when I connect to the computer to download the program...

Isn't there a resistor connected to boot0? Disconnect the resistor and connect a resistor to pull it up.

If it is directly grounded, just lift it up and add a 10k pull-up resistor.

xbxdbd

damiaa posted on 2024-3-13 09:38 Isn't there a resistor connected to boot0? Disconnect the resistor and then connect a resistor to pull it up. If it is directly grounded, lift it up and pull up a 10k pull-up resistor...

I made the jumper, but the chip still has no response. There is another phenomenon. I drew a red circle here. My schematic diagram is like this. Logically, it should not light up during the power-on process, but it keeps lighting up. Could it be that the main control chip is broken, so the program cannot be burned?

damiaa

Don't worry about PA15's legs yet. The program hasn't been burned in and the microcontroller hasn't started working yet. Don't worry about this yet.

xbxdbd

damiaa posted on 2024-3-13 10:11 Is your jumper directly connected to the chip? Is the other end of 102 GND? The jumper should be connected to the CPU leg, ...

Is this what you mean?

damiaa

xbxdbd posted on 2024-3-13 10:21 Is this what you mean?

This is boot0, the one connected to r3 is boot1

Boot1 is grounded correctly, the resistor of boot0 (R3)

Remove the pull-up connector.

damiaa

This is boot0, the one connected to r3 is boot1

Boot1 is grounded correctly, the resistor of boot0 (R3)

Remove the pull-up connector.

damiaa

If it can be burned, remember to restore grounding after burning so that you can run your own program.