Role for FPGA or CPLD with Raspberry Pi

Hi all,

Thanks for pointing me at this Morgaine.

I think there are a few point to consider here I want to throw in. However I want to be clear that I'm very pro getting schools, collages and Uni's more hands on and involved with things like Raspi and FPGA/CPLDs.

First off from a education point of view we have to consider what you guys are talking about and the target audiance. As someone who has teached kids in electroincs clubs and takes part in school engineering contests (as a judge) I had written this blog on my first views of the Raspi in educations. This was followed up by a head of ICT who poested this on Deaign Spark too.

My point is however that education is just not geared up for the Raspi and certanlly not for FPGAs. I ahve spoken to a teacher only yeasterday about this and she confirmed that they have no idea what they are doing. So throwing FPGAs at them will scary them off. The key point she picked up from my blog above is that unless a package is supplied to schools that is clear and simple to use then it will not get past the teachers desk. This sounds harsh, but its so true. Its take two years for the Arduino to apear in school contests.

Moving on to haveing a CPLD or FPGA attached to a Raspi I think is a good idea. The Raspi is limit in GPIO and anything that can help expand this will be good. As a first off I would use somthing like a simple CPLD as a direct access to the GPIO as this will hold its configuration at power up, allow simple patcheing and basic logic circuits to be run from it.

The XAPP058 is a great starting point for someone to generate a JTAP programmer for the Raspi. This can then use XSVF files to program either the CPLD or another FPGA if attached.

At this basic level I think you could then start offering not only programming but some simple VHDL / Verilog to schools and collages. However as pointed out you can't run the tools on the Raspi so will HAVE to have another machine for this. You then have to ask if this is protical. What is the Raspi really doing in this project that you can't do with a PC or some of the specially designed education kits like ther terasic DE2. Find that answer and argue it and then you can push Raspi and FPGA tech togetter into schools. However in my view, use pre complied XSVF files to teach logic and basic electroincs via the Raspi.

Moving up as I said you can then add larger FPGAs like the Spartan-3, good price point and enough flex for entry levels. However I think what your offering is a high end education kit or a really nice development kit.

Anyway just some of my ideas tio throw in - truned intoa long answer so sorry about that but would be intrested to see anyones developments and hear your views too.

Paul

(@monpjc)

"Logic!  Why don't they teach Logic at these schools?" asks the Professor in The Lion, the Witch, and the Wardrobe.  When I was a lad in USA schools, there was no instruction in Logic, and I imagine it's no different today and probably no different in the UK.  I had to learn Logic on my own.  My mother actually got me started by buying me a dice-based logic game called WFF 'n' Proof, probably because she didn't know what to get and the sales clerk said it would be "educational".  WFF 'n' Proof was pretty useless as a game since there wasn't anyone to play it with, but the instruction manual was a terrific introduction to symbolic logic and got me hooked on the idea of solving logic problems automatically.  The Madison, Wisconsin public library had a terrific collection of computer and electronics books, and before long I was making RTL circuits using schematics from the GE Transistor Handbook.  Then 7400 TTL showed up at an impressionable age and suddenly I could easily make really good logic circuits.  Bliss!  CPLDs and FPGAs brought it up to the next level, where you can do far more and not have to worry about the details of logic minimization and having to re-wire to fix errors.  Real chip design on the cheap, no masks, no minimum quantities, and no NRE.  Double Bliss!

My point here is:  So what if it's impractical to teach logic design in elementary/high school classes?  The kids who will run with it will do so on their own if the tools are available and cheap and there is good documentation.  Kids who don't want to bother with logic -- or thinking in general -- aren't going to be sold no matter how good the curriculum is.  To quote Jean-Jacques Rousseau (Émile, from memory): "A child should not learn by Rote what he cannot understand.  He must learn by Experience what he can understand."

@John:  My answer:  Exposure.

Kids can't get enthused about things that they've never heard about.  A Pi sitting in the corner blinking its LEDs during science class is a very powerful attractor for youngsters with the right mental disposition.  And if you can work it into science experiments as a tool to turn things on and off, you're halfway towards giving future engineers a lifetime of enthralling fun that just happens to be very valuable to society as well.

The process is self-selecting, but it needs a spark.  And in this new Pi era, sparks are cheap to provide.

None of this argues against your point that many kids will find out about technology on their own, which is very cool.  But not everyone will, and given the price of a Pi, providing additional exposure in schools has an astronomic benefit/cost ratio.

Morgaine.

@John:  My answer:  Exposure.

Kids can't get enthused about things that they've never heard about.  A Pi sitting in the corner blinking its LEDs during science class is a very powerful attractor for youngsters with the right mental disposition.  And if you can work it into science experiments as a tool to turn things on and off, you're halfway towards giving future engineers a lifetime of enthralling fun that just happens to be very valuable to society as well.

The process is self-selecting, but it needs a spark.  And in this new Pi era, sparks are cheap to provide.

None of this argues against your point that many kids will find out about technology on their own, which is very cool.  But not everyone will, and given the price of a Pi, providing additional exposure in schools has an astronomic benefit/cost ratio.

Morgaine.