mini j-link segger connector

[jersey99]

It's hard to know which orientation to plug in the segger j-link mini onto the Marble-mini. It would be good if some hints are added, possible options:

1. Add a mating connecter with the segger j-link notch
2. Add a note on the silkscreen. I understand that J16 mark on the silkscreen gives orientation, but a little more indication on the silk screen would help double guessing and having to look at the docs every once in a while.

@ldoolitt @yetifrisstlama this would be a "good to have" before the next spin.

[michael-betz]

Assuming you mean J14 (MMC JTAG)

This doc about cortex debug connectors suggests it should be a FTSH-105 connector.

Looks like we can just install the shrouded version, if we can come up with the right part number.
FTSH - 105 - ???

Here's some options on digikey which might fit too:
https://www.digikey.com/short/z4fr8r

Going by the image, this might be the one they use in the doc:
https://www.digikey.com/product-detail/en/samtec-inc/FTSH-105-01-L-DV-K-TR/SAM13165TR-ND/2649981

[jersey99]

Sorry, yes. To confirm J14 (MMC JTAG).

They all look good to me. :-|

[ldoolitt]

In the comment added to Issue #48, this shows up as

• if keeping J14 "Cortex Debug Connector" make a big pin-1 marking can we use a keyed/shrouded option for J14? Amphenol 20021221-00010C4LF

This in turn was pasted from the to-do file in the marble1 repo. So yeah, it's a known issue.
Changing assignment to Michal, since he agreed in a phone call to at least look into making this change.

[michael-betz]

Note that 20021121-00010C4LF is not shrouded

I'd recommend: Samtec FTSH-105-01-L-DV-K-TR

[ldoolitt]

Note that 20021121-00010C4LF is not shrouded

Looks shrouded to me.
At Digi-Key.
This is the part inserted by Michal, which now shows up in fab2 branch.
Both the library and the instance need the SMD attribute set to Yes.

[michael-betz]

For the 20021121-00010C4LF, how do we know the notch in the shroud fits the connector? It's hard to tell from the drawing if there is a notch at all.

[gkasprow]

In such cases I download 3D models and check with FreeCad, Alibre or similar tool if they fit.

[michael-betz]

Excellent tip!

Looks like there's no notch on 20021221-00010C4LF

[ldoolitt]

Right. Shrouded but no notch. The connector shipped with the Segger demands a notch.
The silkscreen for the footprint should also show the notch, so its chance of getting assembled right is more than 0.5.

The FTSH-105-01-L-DV-K-TR you mentioned earlier looks a little funny, and is three times the price, but will probably work.

[michael-betz]

The FTSH-105-01-L-DV-K-TR is the debug header recommended by ARM. I guess that's also why it's 💰💰💰

[ldoolitt]

FTSH-105-01-L-DV-K-TR placed as of commit f78131c.