With motors in hand, I built up a quick prototype. The X27 motors are designed to only move a small pointer. They draw so little current (under 20ma at 5v) that they can be driven by PIC and AVR micro pins directly. Soldering wires to the thin pins of...
I designed my PCB in my favorite software - Diptrace. The motor footprint from switec's datasheet was missing a few key dimensions. It took a bit of measuring with a caliper and calculating hole sizes, but I was able to get all the dimensions correct...
While the PCB's were being built, I turned my attention to the pointer issue. The switec motor's have a 1mm shaft. A good pointer has to be a press fit on the shaft, but not so tight that the mild steel motor shaft is bent while pressing the pointer...
With the PCB and parts finally back, and working pointers printed in safety orange, I started assembling. About 10 minutes of soldering later, the finished board looked greatNow I needed a face for my gauge. I broke out word for windows (I know,...
Now with everything built and wired up to the Arduino, I had one last step. I needed to get my PC to share its processor utilization data with the Arduino. I figured I would be writing up some software in C# to do this, but found an even simpler way....
While I do have a working system, I still am not done with the project - I'd like to ditch the Arduino and use a PIC or AVR to drive the motor. I'd also like to get the entire assembly mounted in a more gauge like enclosure. Something that would look...
Did a preliminary BOM today and selected a few key components, incl. the Spartan 6 variant I'd like to use and the SDRAM and Flash devices (may go with a BGA SP6 package with more IO...no risk yet to the design, regardless of what I choose). All...
For those interested, I setup a working directory on git for this project (https://github.com/sfgit/FPGA_Arduino_Shield). I've uploaded a few libraries today also for the FPs and a !very! generic PCB (just the imported board shape and some parts...
Realizing I've got heaps of room on this board, I've gone ahead and tweaked my choice of Flash memory. In this case, I'm still doing SPI programming of the FPGA, though using a Spansion part (at least for prototypes...I'll try and cost this down...
As the project unfolds, I've planned to produce some content - could be a video, could be a doc - that details the process I'm going thru. The first video in that series is posted now on YouTube and available for viewing at: This video really...
Completed the first part of the FPGA wiring for Master Serial / SPI mode - i.e. configuring the FPGA from SPI flash. Created a video that details some of the nuances and aims to explain the wiring in the schematic a bit. Files uploaded to...
FPGA decoupling can be tricky to sort out without some guidance. Thankfully, Xilinx provides a pretty comprehensive PCB Layout guide that has specific recommendations for decoupling schemas for the PCB, based on specific parts and pin counts. I...
Uploaded a heap of stuff to git. Working on video now. This includes two layers of top level documents that show sheet to sheet connectivity between SPI and the FPGA and also have the breakout for the FPGA IO and other various items. Added...
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...