Debugging probe StLink V3 MINI vs MODS ? Why MODS does not work via CN5 connector?

[RnnKrk]

Hello,

I bought the StLink V3. The MODS version. The idea was to have good, handy and slim debugging probe. Well isolated as housed in thermally shrinking tube.

I equip all my Stm32 pcbs with the miniature debug connector comprised of: Gnd, SwCk, SwDio, Swo so such a slim probe would be very appreciated.

Fist I connected to the connector CN5 and... got message that "Error... No device found on target". Hmmmm. why?

After an investigation I discovered the differences between version MODS and MINI. Photo shows that MINI has more components assembled.

So I moved to CN2 edge connector (pins 4,8,13) and now my probe works well :-).

So could you please clearly mention in the datasheet (as engineer for engineer) that MODS differs from MINI and how? I agree that you formally inform "...This function is available on CN2 (STLINK-V3MODS) and CN5 (STLINK-V3MINI)...." but such a warning would be useful, I guess.

Could you reveal what components should I add to my MODS to get signals on CN5 connector? I guess they are buffers giving more security for delicate CN2 inputs of probe board? The next probe I will buy will be the MINI (and I will remove the CN5 smd connector) but I would be happy to reinforce my current MODS too.

All the best

Robert

[TDK]

Would be nice if they just provided the schematic like they do for so many other boards. No idea why this one is an exception.

[Andreas Bolsch]

As you can guess from fig. 8 in UM2502 there are 8 resistors missing on the bottom side. For each of these resistors, one pad is connected directly to a pad on CN5, the other one directly to CN2. The missing resistors are due to the fact that STLINK-V3MODS is intended to be soldered on a PCB, they would be in the way. Most certainly any value in the range 100 ... 1k Ohms will do. The two missing 5-pin devices on the top are connected to T_NRST and T_JCLK, respectively, but they're apparently not necessary as you got it working via CN2.