st-link doesn't connect my laptop to the board

[lzhan.21]

I have stm32F407 discovery board and I have downloaded and installed the ST_LINK USB driver on my laptop running window 10, but when I plug in the discovery board, the error message pops up saying the USB driver is not recognized, in the device manager, it showed unknown USB device. I tried several ways,like uninstalling the unknown USB device, updating the driver, installing the driver again. Restart the computer and plug in another USB port, nothing seems to work. It worked before, right after I soldering the header pins onto the discovery board, My laptop couldn't connect to the board. I tried a new cable today, I still have the same problem. Can you help me to find a way to solve this? It's really painful to be stuck in the same place again and again. Thanks!

[lzhan.21]

A little more info:

After soldering the header pin, I visually inspected the pins, the adjacent solder spots are not short circuits. Then I used the multimeter to check the continuity, during this time I may have accidentally put the multimeter on the resistance setting, but quickly I changed to continuity. Any suggestions as to what else to check on my board? Thanks!

[Andrew Neil]

Use Alt+PrintScreen to capture just the current window/dialogue - rather than your entire desktop.

This one is telling you that the problem is with the USB connection between the PC and the ST-Link - you need to fix that before you can connect from the ST-Link to the Target!

 

This one shows that you have a number of USB problems:

 

Is it a genuine ST-Link, or a cheap clone?

[Andrew Neil]

Post a schematic of your connections.

Also, some photos of your setup could help.

[lzhan.21]

I got the board stm32F407G from Digikey and the schematic of the board is in its documents. Any suggestion is appreciated!

[Tesla DeLorean]

That's ST's schematic

What would be more interesting is what you wired up, and the header you attached, at the time you broke it..

This looks to be a boot-leg/clone board.

If you electrically damaged it, no amount of cable or fiddling with drivers will fix it. Did you erase the F103 with the ST-LINK firmware on it?

[Andrew Neil]

@lzhan.2​  "It worked before, right after I soldering the header pins onto the discovery board, My laptop couldn't connect"

So what "header pins", exactly, did you solder onto the discovery board?

Certainly sounds like you broke it in the process. ��

[lzhan.21]

Hi, Andrew,

I soldered the two male header pin connectors onto the board where p1 and p2 are in the schematics, as on the board p1 and p2 are just through holes.

[lzhan.21]

I just run some sample programs on it and didn't know how to erase the St-Link firmware. After soldering the header pins, I didn't connect any wire to them, just connect the bare discovery board with the mini USB cable to my laptop. Even before soldering, the USB connection is flaky, I have to try several times to get it connected to the laptop. But once it connected, it worked just fine. Until the next time when I have to connect it again, my laptop will say it couldn't recognize the USB device. I have to try it again. Now it is completely dead. Where can I get a reliable board with pins already soldered on?

[Tesla DeLorean]

The PCB looks to have "PCBWAY" or similar board# tagging at the northern end.

I suspect it is a board sold without the primary headers on the east and west sides populated.

Just soldering these onto an unplugged board shouldn't be a big problem unless some of the power pins were shorted, and the regulator or diodes blown out.

One would need to go in with a scope or meter and check assorted power and functional nodes in the circuit.

WaveShare is a board partner with ST, I'd expect they'd have F4-DISCO boards (in blue these days?), or an assortment of their own break-out boards.