Electrical – How to debug a program using FTDI in STM32CubeIDE

Somehow it works again, but I'm not sure exactly what, since I tried a lot of things and one of them must have made debugging possible again (but it worked after restarting CubeIDE, although I did several times before without luck).

What I did was:

• Changed a few settings in the IOC file (just to regenerate it)
• Moved the folder out of git, renamed and imported it again
• Changed USB cable
• Restarted CubeIDE

One of those must have 'fixed' the problem. Hope it doens't come back by itself again.

Having multiple interfaces connected to a development target is fairly common. When they all go back to the same PC, it's also fairly simple.

You should really make sure that only one source is providing power (ie the positive power supply line) to the target, for example, the USB connector on the board.

Normally each interface should have a ground connection, eg a "common ground" with the target, and by extension every other system the target is connected to. When everything goes back to your laptop over short USB-derived interfaces, you can sometimes get away with being sloppy, but still it's better that each cable assembly have a ground.

Note that an SWD connection typically does not provide power, rather a supply line present on one is formally supposed to be used as an input to a better tier of SWD adapter which will adapt its signaling to the voltage at which the target is operating. You don't show any connection there, which is probably appropriate; your clone adapter doesn't adjust its voltage anyway, it could (in deviation from tradition) supply a small amount of current to a target that doesn't need much power, but in your setup you seem to have other means of powering the board.

Your drawing is too pixelated to be certain, but it appears that you may be powering the board through the FTDI adapter. While this may work, it is probably unwise; the internal regulator in an FTDI chip is really only meant to power the chip itself, and extremely low power auxiliary loads. Depending on what you are doing, you might get away with that, but really it is not the best idea. Your target board has its own regulator, which you should probably utilize either by feeding power through the USB connector or via some other 5v input line on the board.