Sunday, July 16, 2017


It has been a long time since I wrote about the dsPIC-EL-GM. This thing has turned out to be a very successful tool for me.

Over the past couple of years, this has been the platform for dozens of projects.  In some cases the entire project was done on the board plus a shield. In others, it became the prototype for a purpose built board.

The choice of the dsPIC33EV was a good one.  Besides being 5 volts, meaning inexpensive displays work with it, it is fast, available in a variety of memory sizes (32-cheap, up to 256-huge), has a huge range of peripherals, and PPS.

The decision to put connectors for shields on the board turns out to be critical. Most projects need an LCD.  Hand wiring all those pins from the PIC to the display, plus power and programming (which I seemed to always get wrong) tended to present a barrier to starting new projects. With the shields I can just grab a shield and get started, and all the tedious stuff is behind me.

Plus, by having a standard part, standard display/LED/button pinouts, I have built up a number of libraries that make getting a project started easier and faster.

There are a couple of features that turn out not to have been so useful.  The jumper allowing me to use PIC24EV parts hasn't gotten used very much. I was attracted by the low price of some of those parts, but the 33EV32 isn't all that much more expensive, and it has more memory and way more speed.

Also, I had added a connector offset slightly from the shield connectors to allow me to plug in standard perfboards. But the extremely low cost of custom prototyping boards made that less useful. The demise of Radio Shack also shoved that feature into obscurity.  It was a significant advantage to be able to run down to the corner to get a perfboard. Now that it has to be mail order, I just keep an adequate supply of prototyping shields on hand.

I have been tempted to build another PIC-EL for one of the PIC32s. The PIC32MZ series offers blinding speed, crazy big memory, and even floating point. By having a flexible platform, the need for a DIP package is mitigated, and the price of the MZ, while not cheap, isn't really crazy. I had a lot of fun doing a graphics card with the PIC32MX250F128B, so I feel like the PIC32 isn't that alien of an animal.  But that is a project for another day.

I am not trying to sell dsPIC-ELs. However, needed information for building your own is available on gitlab:
  • Gerbers for the dsPIC-EL-GM are available here.
  • And for the proto shields here.
We did kit a few for the high school electronics club, which necessitated creating detailed construction instructions:
  • Build instructions here.
Should you build your own, let me know how you did in the comments below.

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