How do I fix "No STM32 target found"?

[HaYa6174]

I encountered this error when I was trying to flash my custom board with fresh stm32F070C6T6. I used st link v2 for debugging. I updated the firmware of st link v2 right before debugging.

NRST floating, BOOT0 connected to 3V3 -> failed (in any mode)

NRST floating, BOOT0 connected to GND -> failed (in any mode)

NRST connected to GND, BOOT0 connected to 3V3 -> failed (in any mode)

NRST connected to GND, BOOT0 connected to GND -> failed (in any mode)

I also tried both on Windows and Mac(m3), and was not successful.

I also tried Cube IDE, Cube Programmer, and st link utility, but all did not work.

I also tried to use DFU, but it also failed. (no dfu detected)

I measured the voltage to be 3.16V and ensured the wiring was ok.

Now, I have no idea what I should do to fix this issue. Can anyone point out where it went wrong?
Thanks.

[Andrew Neil]

There must be something wrong with your wiring - your ST-Link is seeing 0V !

Are you sure you have the pin numbering correct?

The view is looking at the pins in the ST-Link:

[HaYa6174]

 

Here is my wiring. The pin header is shown at the corner of the black PCB, and connected to the st link v2.
Then I tried to connect, but it did not work.

 

[Andrew Neil]

The 3V3 on your board needs to connect to VAPP:

[HaYa6174]

One of the header pins is 3V3 and is connected to VAPP.

In the previous photo, the first pin from the left is the 3V3 pin.

[Mike_ST]

Hello,

Could you try to connect with the other modes (Normal, Hotplug, etc...) :

Please make sure to pull-up the NRST signal to 3.3V.

Maybe I'm wrong, but I don't see it connected to anywhere.

[Andrew Neil]

Are you sure you have the ST-Link pins correct?

ie, are you sure it's pin 1 - not pin 19 ... ?

[HaYa6174]

I have tested all of the modes and did not work.

Plus, I think NRST can be left floating since it is pulled up internally, so I am not connecting it anywhere.

[Mike_ST]

Ah yes ! the red line on the ribbon cable is pin 1...

[Mike_ST]

Yes you're right, I have just checked the datasheet:

[HaYa6174]

I am not 100% sure since I am new to this, but I could not find anything wrong here. I also thought that I should use pin19 instead of pin1, but when I swapped pin1 with pin19, my power LED did not light up.