Applicable_Robotics wrote:Hello Briarios,
Have you made any progress on the testing of the latest batch of boards?
I am considering building a few CM BoB's for a project, and it would be quite helpful to have something to build from.
On a related note, how have you managed to create matched resistance routed pairs in eagle?
Hi Nicholas and guys
The latest batch are on their way from Shenzhen at the moment so i won't be able to test them until the middle of next week unfortunately.
To answer your second question and for anyone who wishes to know, I used a program called Saturn PCB to workout what width the traces needed to be and also how far apart the traces needed to be from each other. Then I did a rough outline in eagle on where the traces needed to go, then once I made sure the gap between the traces were uniform, I clicked on the meander button in eagle to determine the length of each trace and then I extended or shortend one of the traces so that they both line up roughly to within a 5% threshold I had set. this is to ensure that both traces conform to the correct ohm values for each of the pairs.
Also note that while it is doable I strongly recomend not using a 2 layer PCB for this, for curcuits that use Ethernet or USB you need a 4 layer PCB or greater to achieve the results needed and to conform to the USB and Ethernet standards.
http://rpi.pmfg.me -- Test board Eagle Cad Files.