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Xlink hardware
Posted: Mon Dec 14, 2009 4:27 pm
by leon_heller
Is there a preferred connector and cable for Xlinks? I am using 2x3 IDC headers and six-way ribbon cable at present for connecting two SFE boards, but it would be nice if a standard could be agreed. Ideally, the cable would have twists in the conductors, so that PCB connections would be the same at both ends - something like the transputer link cables from 24 years ago.
If anyone wonders why I'm connecting two SFE boards together when boards with four cores are available, it's for testing Heater's Propeller Xlink implementation. Someone on the Parallax forum has come up with some code that looks like giving 10 Mbit/s.
Leon
Re: Xlink hardware
Posted: Tue Dec 15, 2009 12:45 am
by nisma
I prefer micromatch connector.
Re: Xlink hardware
Posted: Tue Dec 15, 2009 4:05 pm
by leon_heller
Can you use a crossover cable with them?
Leon
Re: Xlink hardware
Posted: Thu Dec 17, 2009 12:27 am
by leon_heller
Here is an Xlink cable idea of mine for the XMOS kits:
The shells were cut down from longer ones, it's difficult to get hold of single ones although they are made.
I'll make up a second cable and try a loopback test.
Leon
Re: Xlink hardware
Posted: Mon Mar 07, 2011 6:41 am
by russf
So a standard connector has not been proposed?
I have a board that I want to be able to double up in an application. So (unless I've screwed up) the attached molex connector pinout will, if the lugs are ground off and it's given a twist between boards, link the two boards symmetrically via LD, on each board. (See file, below)
The advisability of putting voltage on the outer conductor will vary with application. I think I can get away with passing across 5V and regulating to 3.3 and 1.0 on the other board, but I may just strap across the adjacent boards.
I'll be keeping this as short as I can, so I'll drive the Tx ends with 74AUP2G17, as recommended here:
https://www.xmos.com/download/public/XS ... 1.1%29.pdf
Edit: I switched the order of the send and receive signals to match the natural order of the port definitions - mainly because I can copy and paste them more easily in my schematic editor. Looks like nobody had downloaded the first version of the attached file.
Symmetrical 5w link cable rev0.2.png
Comments welcome.
Re: Xlink hardware
Posted: Tue Mar 08, 2011 9:58 am
by Heater
Leon,
How is it going with that Propeller Xlink implementation? I was just amazed that it's a year since I last thought about it much.
At the time I had a doubt in my mind that the G-Links could be slowed down enough to work with that Propeller interface. Looking at the configuration registers there seems to be less scope for adding large numbers of clocks to the G-Link bit periods.