SWAMP05 is going out the door today! (well actually over the internet, I guess that counts as a "doorway") Boy did this thing turn out to be harder than I thought. Because I was going for 2 layer (for cost and turn time issues, remember: high quality, fast, cheap -- any two. This had some major implications for the high speed differential interfaces: USB and Ethernet. It turns out it's very difficult to get the right impedance with only two layers. I finally worked it out.
If I can figure out how to post a picture here I'll send a plot of it. So now we should probably start thinking about Gen1 details, such physical size, what case (these two go together. SWAMP05 wound up being 4.3" x 3.6". I don't see Gen1 being any smaller. There are a lot of connectors to put on it, so I don't think my original idea of 4x3 with the 3 as the back edge with the connectors working, it just isn't going to fit. If we put the connectors on the long side (as I did in SWAMP05) the smallest dimension it can be is 4", the smallest the other could then be is about 3.5". They could be larger. Based on previous discussions I think I'm going to put a USB hub on the board, so we will have 4 USB type A jacks, even with stacking that takes up a lot of room for full size jacks. I envision two stacks of two jacks. I was thinking originally of doing two USB with an RJ45, but now we have 4, AND the 2USB-1RJ45 don't have builtin magnetics for the Ethernet. So I'm looking at two stacks of two USB, single Ethernet by itself, stacked RCA jacks, TOSLINK, HDMI and DC power. BTW Toshiba no longer makes optical audio modules and they have the trademark on TOSLINK, so I guess we should call it something else. The other big thing we need to decide is what we are going to do about WiFi. I personally like the concept of using the Wizfi630 module which does everything for us without needing any processor resources or drivers on the wandboard. Others want to use the builtin WiFi module on the dual wandboard. It's cheaper since it is already there, but you need to get all the right drivers installed etc, and it's difficult to get all the functionality we can get from the Wizfi630. Then there is the issue of balanced output or not. Balanced adds to the cost and complexity, but is still easier to do on the main board rather than on a "daughter board" which can be done. If it's on the main board then everyone is paying for it. In the case of HDMI it is litterally an extra 95 cents connector, but balanced takes quite a bit more circuitry and quite a bit of extra space. We are probably talking at least an extra $75 to add Balanced. Do we want to add that to every board or have available a $150 add on board which has to somehow mount in the box and connect to the main board. If we do the add on board then the main board and case have to be designed for it. Although once we have a "modular system" there are other add on boards that could be developed. Just a few thoughts. John S. ------------------------------------------------------------------------ JohnSwenson's Profile: http://forums.slimdevices.com/member.php?userid=5974 View this thread: http://forums.slimdevices.com/showthread.php?t=97881 _______________________________________________ discuss mailing list discuss@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/discuss
