pcbpowervoltage
An adapter board (to a card edge connector like PCI Express x1) is needed to be designed to for the breakout board below. This should involve replacing the board's screw terminals with some male rectangle connectors, with will be soldered to the adapter board as well.
However it seems that the screw terminal have a pitch of 3.5mm, but no rectangle connectors with a pitch of 3.5mm can be found (at least on Digi key). Do such connectors exists, or is there a better way to make the connections?
Looking through the datasheet it looks like the CC6678 can operate in root complex mode so you should be able to connect the two. I did a similar board for testing a large batch of pcie cards.
If I were going to try it I'd start with a 4 layer board. You're going to want nice 100Ohm differential pairs to connect your lanes together. It only supports 1 or two of them so that shouldn't be a problem. Just run them over a GND plane on layer two. Just follow good practice here for routing HS signals. Oh and Tx -> Rx, and watch your polarities :)
I saw the clock generator you picked from your other post, I'd probably put a 1->2 fanout buffer and drive one to each of your pcie slots.
You're going to need to generate a reset pulse for the cards as usually the mother board would do that. You could just slap down a simple supervisor that monitors 12V and tie it's reset output to both connectors. Maybe add a pushbutton too so you can reset manually during debug. I used a Linear LTC2916CDDB-1#TRMPBF.
You're going to need 12V and 3.3V to power the connectors. I just used a standard desktop pc power supply because I had a bunch and they're easy to get. I just used a standard mother board power supply connector (Molex 44206-0007) and I put a little toggle switch from PS_ON to GND to turn things on and off. Oh and throw in a few 100uF tantalums on each rail for good measure.
Don't be nervous keep the lanes short, match the impedances and you should be fine.
Here's a pinout if you need one:
My hypothesis is that the FPGA in the schematic is drawn as multiple sub-components along the lines of U51A, U51B, U52C, etc. U52C was intended as U51C, that's the error. Even though there is only one sub-component of U52 present, Eagle adds the whole IC to the board.
** I've made up the designators U51 and U52. The images in the O.P. have low resolution, and the designators aren't readable. I'm guessing that slender vertical component on the left is the connector, and the group of components on the right is the FPGA split into multiple sub-components.
Best Answer
Phoenix contact manufactures board-to-board connectors that use 3.5mm pitch, they're actually quite common. It's a bit bulkier than the header strip, but it will work, take a look at this:
Phoenix Contact - Product list - Headers (press in)
Also, check Farnell and Mouser if they are available in your country, you'll definitely find something that suits your needs.