ST-LINK V2 not finding target on a simple demo board I made

[stmdude]

Using the Nucleo L412KC as a template, I fabbed a tiny test board to see if I could make my own kit.

It is extremely basic, but when I connect the 3V3, GND, NRST, SWDIO, SWDCLK, none of the reset modes in the IDE result in the STLINK detecting the chip:

Starting server with the following options:

Persistent Mode : Disabled

Logging Level : 1

Listen Port Number : 61234

Status Refresh Delay : 15s

Verbose Mode : Disabled

SWD Debug : Enabled

Target no device found

Error in initializing ST-LINK device.

Reason: No device found on target.

Here is the schematic:

See, extremely basic!

Here is the layout:

I'm using a V2 (not a V2 ISOL). On the 20-pin header I connect:

7 - SWDIO (my pin J2.6)

9 - SWCLK (my pin J2.5)

15 - NRST (my pin J2.2)

20 - GND (my pin J2.8)

1 - my pin J2.1

When I try to program, I tried all 5 reset modes, but I notice the power doesn't even come on during programming. I tried using VDD 3.3V pin 19 to my pin J2.1 VDD, and my test LEDs light, but the device is still not found.

Either I messed up the schematic, did a bad solder job with the components, or I'm not setting up the IDE studio debug config correctly.

What is the next level of debug I should investigate? I'm stuck.

Thanks!

Here's my debugger config (I tried all reset options):

[Peter BENSCH]

Welcome @stmdude, to the community!

J2.1 is a ST-LINK connection to measure the voltage at the (your) target, NOT to supply it.

Can you also upload photos (front and back) of your ST-LINK/V2?

Regards
/Peter

[stmdude]

Hello Peter,

Thank you for replying.

Here are the images you requested. Do they help?

[Peter BENSCH]

Thanks, yeah, great. I just wanted to make sure you didn't have one of those colourful ST-LINK clones in a tin can, which I'm pretty sure it can't work with.

But as I said, the ST-LINK/V2, pin 1/2, can't power your board, you'll have to do that externally.

You should also connect your target correctly to the ST-LINK, as your purple wire is connected to pin 8 and the black wire to pin 10, both of which have no function. In UM1075, figure 10, pin 1 is shown somewhat confusingly. The best way to remember the position of pin 1 is to look at fig 9, where the red stripe of the ribbon cable marks pin 1 -- figure 10 must be viewed rotated by 180°, so to speak.

Hope that helps?

Good luck!
/Peter

[stmdude · Accepted solution]

Thanks Peter.

I turns out I had the right orientation, but the rubber shrink wrap tubing had slid down the black wire and it wasn't making contact with the pin! In addition I also need to run the voltage back from VDD to Pin 1 of the V2, and use software reset.

It works, I'm pleased.

Thanks, for the help, I wouldn't have thought about that pin 1 VDD target issue.