I have been using stm32f429 Discovery board for a while. recently i tried to use it for programming a blue pill using onboard St-link v2. But it wasn't working even though all connections are okay. Later i figured figured out that target VDD pin which suppose to return the target voltage to St-link MCU has a unfitted resistor R13 footprint. I checked the schematic and it says the R13 is unfitted. As a result the target VDD pin is totally separated from st-link MCU.
So whats the remedy? should i bridge it? It seems it requires a current limiting resistor. If so what should be the value?
If you need to power the Blue Pill, take 3V off of one of the other pins on the DISCO
If the Blue Pill is powered by it's own USB cable, you should need this connection.
Just need GND, SWDIO, SWCLK, perhaps NRST, and make sure to pull the SWDIO/SWCLK jumpers connecting the F429 chip on the DISCO
Oh Thank You .. Basically i dont have to feedback the voltage...and it works for both 3v3 and 5V supply just not connecting the target VDD pin...i Was trying hard bcz of the same issue i faced while programming using st link v2 standalone programming module.