Change PC104 to PCI-104 in the documentation

[mgm8]

We use the PCI-104 connector for stacking the modules, and not the PC/104 (They are not the same).

Differences between the connectors of the PC104 family: https://d2lupdnmi5p5au.cloudfront.net/i__srcae02f9c69ae109a69a5ed454942655bf_par1a3c1eb4506a5f22486e2677b9cb9c0d.jpeg

[mariobaldini]

Interesting observation! We've been using the wrong nomenclature for a long time...

What is the partnumber of the right connector that is used? I know that there's a lot of subtle differences (pin exact height... attach force... gold plated.. etc).

[mgm8]

Searching about that, i found some new information:

There's a "official" specification for the PC104 family: https://pc104.org/

PC/104: https://pc104.org/hardware-specifications/pc104/

PCI-104: https://pc104.org/hardware-specifications/26-2/

Reading these specifications, i think we are using a PCI-104 with wrong pitch distance. The PCI-104 uses a PCI connecton with 120 pins and 2 mm pitch distance (Even with 120 pins, they kept naming it as "104").

I didn't find any vendor selling a PCI-104 connector with 104 pins and 2.54 mm pitch, so this variation probably doesn't exist.

Most vendors name the PCI connector of the PCI-104 pattern as "PC/104 Plus". Examples:

https://www.digikey.com/product-detail/en/te-connectivity-amp-connectors/1375795-4/A112097-ND/2329988

https://www.digikey.com/products/en?keywords=M22-6003005

This problem will not affect the integration between our modules, but we need to review our PC104 connection to use the correct pattern in the next versions.