EDMCONNECTORKIT and EDM Connector

[Tim Smitty]

Hello all,

     I am currently messing around with my newly designed EDM carrier. I have run into a major problem and looking for help/recommendations. First off, I have pinpointed the disaster to my EDM connnector. It seems that there is poor connectivity and if you push the Wandboard completely in with my current connector. I end up with almost no connectivity due to soldermask being too short on the Wandboard. The part I currently use is the: JAE electronics MM70-314-310B1-1-R300. While everything seems to fit fine, I have significant issues trying to get the unit to boot and have tested several pins on the carrier to see if they are connected to the same pin on the Wand. I get nothing, sliding the board just a bit further out of the connector proves to resolve this issue, however is not a viable fix. It may also be against me, but I've hand placed this connector. Not sure if this is causing the issues??

Long story short, I'd like to change connectors and have found the EDMCONNECTORKIT at Digikey and Future. The problem that arises is there is no datasheet associated with this kit. No reference to the part number, no recommended footprint, etc, etc. I have also looked up Foxconn's AS0B821-S78B-7H and found no places to download the datasheet. It seems almost impossible to get a datasheet, parts (except in other countries not the US) or any sort of reference for the EDM connector.

If someone has it, can you please provide the datasheet for the part found in the EDMCONNECTORKIT.

Also is anyone else using JAE electronics MM70-314-310B1-1-R300, if so, do you have issues or is it a true hand soldering problem. Mine may be hand soldered, but it looks like a machine did it, thus I don't attribute any problem due to this. The soldering person did a really fine job (not me).

Thanks again!

T

[Chris Pettus]

I have seen many posts asking about the EDM connector, which is a MXM Type 3 with 314 pins..  The connectors specified in the EDM document are hard to source while the JAE connectors are available from sources like Digi-Key and Mouser.  The JAE connectors are not a exact match but they do work.

The JAE connectors are missing a few pins (E1_10, E2_10, E3_1 and E4_1) but these pins are VCC and GND which is supplied on other pins as well.  So the Wandboard will still function without these pins.

The connector MM70-314-310B1-1-R300 does not have a matching footprint.  The alignment pins and metal tabs on the sides do not have the same dimensions as the MM70-314-310B2-2-R500 (or Foxconn, etc.).  I think if you are okay with having a different footprint on the carrier board the pins in the socket will connect to the Wandboard.

The connector MM70-314-310B2-2-R500 does match the footprint of the other MXM connectors but this is a short connector which only allows 1.5mm between boards.  When used with the Wandboard there are a few components on the back that will collide with the carrier board.  I only have the Wandboard Solo but the components that collide are the inductors L3, L4, L5 and L7.  You can still use the connector but you have to leave the Wandboard tilted up a little.

I am attaching my Altium PcbLib for the footprint I created.  The embedded 3D model is the JAE MM70-314-310B2-2-R500.  I might be able to export to a format for other CAD packages.

On your booting or power up issue check your connection to GPIO3_12 which is pin 255 on the EDM connector, pin EIM_DA12 (pad M24) on the i.MX6.  This pin is shared with boot mode select and the circuit that I had connected on my carrier board was pulling this signal low causing the i.MX6 to attempt boot from a different SD card.  There are also several other pins that are shared with the boot mode configuration, check the Wandboard User Guide schematic for EDM pins that also connect to the boot mode configuration (look for pins that connect to page 6).

A good reference on the connectors available is the MXM graphics module page http://www.mxm-sig.org/main.cfm?action=suppliers&Category=2

Regards,

ChrisP