P2 EDGE and P2 80-pin adapter / socket layout questions

PropGuy2

In anticipation of the new P2 EDGE and 80-pin adapter PCB forthcoming, I have begun to layout my PCB project. In the process I think I discovered a mismatch with the ordering of the P2 EDGE, 80-pin socket, and the 80-pin adapter PCB (p/n 64018) pin outs. I am looking at the 5v, 5v, Gnd, Gnd, Gnd pin sequence of the P2 EDGE module - and the Gnd, Gnd, 5v, 5v pin sequence of the adapter and the NC, NC end of the adapter PCB. See the attached pictures. Am I missing something, is the 80-pin socket transposing some pins or ???

Dave Hein

It appears that they copper-filled with 5V instead of GND, which is a bit unusual. Also, the 3 ground pins are not connected together, but they do run to the correct DIL pins. And for some reason they connected the two NC pins together, and ran them to pins on the DIL connector. This should all work correctly, but it does seem a bit unusual.

BTW, if you intend to use the straight 80-pin socket make sure you order the correct one. There is a through-hole version and a surface mount version. I ordered a couple of straight 80-pin sockets, and I received them today. I discovered I accidentally ordered the surface mount connector instead of the through-hole one. I'm going to have to do another order to get the through-hole ones.

iseries

I hope the documentation is correct because I almost have my P2 Plug and Play board done.

Mike

VonSzarvas

The images look like the pre-launch ones to me. And I thought the pinout was explained somewhere.. maybe in the Product Guide. I can check later today.


In summary- one plane is connected to 5V, and the other plane is connected to the two NC pads (ie. connected to nothing). Some users might want to hook that NC plane to GND, others might want to put a signal or a 3.3V rail there.

On the next Rev of this breakout we have a couple ideas listed:

1. Remove the planes and simply breakout all pins to the headers as they are now.
2. Have the planes permanently connected to 5V and GND, so that the corner pads become a useful way to connect power to the board.
3. something else...

Any preferences?



Edit: The correct Product Guide and Pinout images are here : https://www.parallax.com/product/p2-edge-80-pin-adapter-kit/
Make sure to note the "Bottom View" tag for those pinouts.

Dave Hein

iseries wrote: »

I hope the documentation is correct because I almost have my P2 Plug and Play board done.

Mike

That's an interesting board. However, the vertical header pins might make it difficult to insert the P2 Edge into the connector. Have you checked the clearance to make sure it will fit?

iseries

Yep, have one and measured it, 30mm. It also faces down.

Mike