Updated the schematic over the weekend to clean up the wiring and group signals, sheets, etc. more intelligently. A new version of the source files and a PDF can be found on the git repository. A direct link to download the PDF can be...
Uploaded video no. 3 explaining the schematic overhaul, JTAG wiring (w/ a little background on JTAG - though focused on the implementation), and discussing the decoupling. For a detailed discussion of JTAG, I suggest having a look at...
Made a number of little tweaks this weekend and uploaded a new SRAM document, new SPI multiplexer doc, made tweaks to the top level to integrate these elements and just finalizing some bits here and there. Complete details in github. See...
Uploaded video number 4 to Youtube, showing both SPI Multiplexing with a TI Bus Switch, and also implementing Asychronous SRAM (128K x 16). Next up, power supply!
Had some fun tonight playing around with PCB routing. You can see in the PDF in git or the PCB file (you'll need altium to open it) that I'm all about "pretty". :) Still a fair bit to finalize the routing and design and such but moving...
Uploaded the power supply design to git hub today. The supply is laid out in a way to allow either driving the system from the Arduino's 5V supply or using an external power adapter. The Arduino's 3V3 supply is tiny (very little current,...
Uploaded the layout files to git today with routing completed and some final schematic tweaks. Released gerber files also to fab. Design is looking pretty good and should be pretty close without many major changes since last prototype I'd...
Released a complete collection of manufacturing outputs including Gerber, NC Drill, ODB++, Testpoint files, & Pick and Place. All of these are for building proper prototypes. Expect to have boards in 5 days. 2 Days for assembly, a day...
Made a cosmetic change the schematic (top level) and also uploaded PDFs to Git. One small change to PCB was required to get the cost down (increased via hole dia for QFN LDO from 2mm to 2.54mm...makes "low cost" standard mfg avail)
...But it's enough for the board house to balk at, even if they can't mfg to those tolerances. Oh well, released a slightly modified Gerber to deal with some "roundingness" in the mfg outputs and ensure things are a little cheaper overall (under...
I went ahead and added feedback from the fpga DONE pin via the addition of a status LED. Also added a jumper that enables that feedback to be sent back to the Arduino board. The jumper gives the option to route the DONE pin to the Arduino...
Got boards back from Advanced Circuits today. Look good. Really like the finish on them. They did a good job and boards came back on time (a little early actually) with a bag of microwave popcorn included. :) Mmmm...popcorn....
Boards have been built and worked the first time. Woohoo! Only thing I've noticed so far is that I neglected to tent the vias (cover them in soldermask) under the super small BGA SRAM. This has a nasty effect of making it very hard...
Ok, normally I don't complain about hand soldering stuff because normally it's pretty straight forward but this was a lesson I learned years ago come back to haunt me all over again. Rule #83: Tent the vias beneath your BGAs! Especially if...
Made some updates to the design over the weekend to add LEDs, a nice dipswitch, make the silkscreen cleaner, clean up the pad arrays a bit and a lot more in the way of little cosmetic PCB tweaks. Overall some very important tweaks but in the grand...