Sunday, May 18, 2014

Minima - VFO Troubleshooting - Cont'd

Regardless of what I have tried, my Minima VFO Module does not seem to work, see previous post.  It does not respond to a simple I2C Address Scan from the BusPirate (BP). The problem could be a something simple on the VFO Module, a dead Chip,  the BP, or the connecting wires. I could test the BP and wires if I had a known working I2C device, but I don't.

To fix that, I am going to build a simple stand alone Si570 BreakOut Board, which will only contain an Si570 and Header Pins. If this works, it will be useful for verifying my BP and also it will be useful for other standard ProtoBoard experiments.

Proposed Si570 BreakOut Board
A simple Google search did not suggest a consensus of pin outs for a breakout board, I decided to arrange the pin in Si570 documented order similar to a DIP. The board will be about 0.5x0.6 inches. I guess I should have made the pin row spacing 600mils (not 500mils) so it would fit standard PCB DIP Sockets.

Using standard pin order requires a trace on the backside with the accompanying two via's. Two additional via's will help tie the front and back ground planes together. All soldering for the Headers will be done on the top side, because Homebrew boards do not have plated through holes, and therefore it would be difficult to solder under the Headers on the back side.

I could have included the two required I2C Pullup Resistors, but no, I wanted this to be a generic as possible.

This maybe a very useful board for my future projects, it is a simple task to make several copies while making the first, using the Toner Transfer (TT) Method.



  1. I've been browsing through and reading about your really inspiring SMT Minima build Eldon. My head is spinning a bit, as I am not in any way a digital or software guy and I'm still trying to figure out at what point I want to jump in, or whether to take the easy way out, and wait for someone to come out with a Minima kit.

    My inkling is build mine Manhattan style, beginning with the VFO and controller circuitry. I think most of mine will be built with through-hole components, but I have an SMT ATMega328P that I would like to use, for which I have bought some breakout boards. Your simple breakout board in this post is the kind of thing I think I will do for my Si570.

    Now I must dash over to Osh Park to try and figure out how to design a board. This is all new territory for me!

    73, and thank you for all the great info you put on your website.


  2. Dave,

    I would be happy to share my DipTrace Schematic and Layout Files with you if you think that would be helpful. With the Layout file, it would be simple to create a Homebrew Toner Transfer board (as I have done), or send it to OSHPark for production.

    This size of board is very inexpensive from OSHPark, about $4 for three copies, the wait from OSHPark is about 10 to 14 days.

    Have fun with your Project.