where to start?

[loss1234]

it seems there are so many options. DSp chips, fpgas, arduino, etc etc

what i'd like to do is start by learning one system. some people tell me to start with something that allows for C. some say assembly.

i dont know either so i will have to learn..

but id like to learn something that lots of books and code is out there already


i am very serious about jumping into this but is such a wide field


any advice appreciated on platforms, books, dev brds,et

thanks!

[Rykhaard]

I recently took the plunge and jumped into it purchasing the PICkit 3 from www.microchip.com
There's a huge amount tutorials available for it and it were cheap at $70 U.S.
PICs available for it allow you to program them in C++ and assembler as well as some version of Basic. Though, I don't know yet which PICs, are open to which languages.
I haven't gone any farther yet than reading the beginnings of tutorials but I will in time, be teaching myself, to begin transferring some of my circuits to, PIC operation.

[loss1234]

let me ask (and i must say I am excited that you too are getting into these things as I always respect what you do!!!), can this chip do things like shift registers, oscillators, a/d, d/a? do you know if its an 8bit or a 24bit?


what are some of the things you want to learn to do with it?

and i wonder if there is a book on this one.\


i might just go ahead and order it

thanks so much

love your forum by the way

[JovianPyx]

There are C compilers for PICs, but I don't believe they are free. MPLAB from Microchip contains a free assembler (which I have used).

dsPIC chips have more DSP capability than PICs, but many modern PICs have a built in DAC and ADC and can do some DSP though with a bit more effort than using a dsPIC.

PICs and other similar devices can do LFO, NCO (numerically controlled oscillator), EG, you name it. The limitation is it's rather low clock rate. These devices also have a limited number of writes available to the Flash program store. You would need to read the datasheet on the device of interest, but the number of write cycles is in the low thousands, some as low as 1000. This means that you write your code, send it to the device for testing and once you have what you want, you stop. Of course, if you've not used many write cycles, you can still do updates and bug fixes as needed. The point is, that it's not meant to be reprogrammed an infinite number of times.

Selecting a device depends on your end intentions.

For creating a board that has a specific function that will not change after development, PICs, dsPICs and related devices are great because the program is stored in Flash - meaning when you power it up, it's live. Monosynths are possible with reasonable complexity. Polysynths - perhaps - but not very many voices if complexity is a focus.

I cannot speak for "true" DSP ICs (such as Shark), I've never used them. They are fast (hundreds of MHz clock speed) and efficient. They are capable of polysynths with reasonable complexity.

An FPGA is _very_ powerful, rivaling traditional DSP ICs, even modest sized ones will support a fairly complex complete polysynth (I've done 8 and 16 voice polysynths in smallish FPGAs). The downside is that you need to learn an HDL (hardware description language) such as Verilog or VHDL. The languages themselves are not horribly complex in my opinion, but the use of them requires a change in thinking from "programming". HDLs are not programming languages despite what they look like. If you are accustomed to thinking in terms of counters, blocks of RAM, gates, adders, subtractors etc., you use the HDL to connect these things together to make a functional system.

Unlike PICs, dsPICs, AVRs, etc., FPGAs are not Flash based, so they must be programmed at each power up. This is normally done one of two ways. 1) FPGA systems will normally have a Flash RAM on the same board which is used to programm the FPGA at power on. 2) An FPGA (which is static RAM based) can be programmed at any time manually via a JTAG interface. Because FPGAs are static RAM based, they can be programmed an infintite number of times.

The software I use to "compile" an FPGA design is called ISE (from Xilinx) and is free. There is a "buy it" version that has more features, but I'm told isn't all that much better than the free one, especially for hobbyist use.

I've purchased FPGA development boards (which support my synthesizer designs) with prices from $50 to $300.

If you're interested in what I've done with FPGAs, the FPGA link in my sig will take you to my FPGA website where you can find descriptions, source code and sound samples.

[monokinetic]

Hi loss1234,
If you are going to learn about embedded processors then I would say that C is lot easier to wrap your brain around than assembler. Plus learning C for one embedded device will set you up with the knowledge to go on to other devices, assembler is often quite device specific. Personally I couldn't handle assembler, bit too deep for me

I have used both the Microchip C compiler and SDCC for developing PIC based stuff (nothing fancy, flashing LEDs on an off is about my level!). The Microchip C compiler is available as a student edition,which is free. Last time I checked you could compile up to a limited size with the free version, but I never hit the upper limit in my experiments.

SDCC, found here:
http://sdcc.sourceforge.net/

is a totally open source C compiler which supports PICs. This is free and there's loads of info online for using it. I played around with it a bit during some Midibox experiments. (I can recommend having a look at the programming sections of the Midibox forum as well, loads of useful info there).

The other cheap hardware route to go is Arduino, which runs on an Atmel chip. I don't have much experience with it, but one friend of mine uses it with the Wiring programming environment to do some pretty cool stuff as well.

I'd say look at learning to program as the main objective, then the skills you learn will be portable to many different processor platforms and toolchains. The key IMO is to get your head around the actual programming concepts, then you can apply that background knowledge when learning the syntax of different languages.

HTH

David

[droffset]

I have an Arduino but haven't put it to much use. Not really sure what to do with it. Most of the projects on the web look like little proofs of concept that you do, see that it's working, then take apart. Some are great though, like the MIDIvox which certainly has potential as a starting point but I wonder if it also highlights the platform's limitations. The MIDI to Gameboy synth stuff is also cool. But is that basically it? Can the Arduino do one, maybe two main tasks and that's it?

Since I've had my head in CMOS land for a while now the FPGA stuff sounds interesting (the way ScottG describes it) just for the reason that it appears to be a methodology I'm already thinking with. Sounds like a mega Lunetta, to be honest. Kind of dreamy if that's the case.

No real point to this post, just thinking out loud.

[okvern]

Hi loss1234 (dan),

Just at a guess, considering your posts here and on Synth DIY, I'd say that you'd be happiest starting with an Arduino. The Arduino IDE is cross platform (so it'll run on the Mac OS, which I recall you have), it's a hybrid C/C++ environment (life is too short to learn assembler for a specific chip--in my opinion, of course), and you can connect to the board via USB. The IDE is free; the boards cost around $20.

There really isn't a simpler way to get started--the whole point of the Processing/Wiring/Arduino approach is to get artists connected with programming and hardware.

Once you get the hang of things, you can use your Arduino board as a development platform, and deploy circuits using just an ATMega 168 (or 328), a crystal oscillator, and a couple of capacitors. Cheap!

There are many examples of synth-related projects in the Arduino forums, or via a simple Google search.

Note that the Arduino itself is not ideal for generating sound. It's not terrible, it's just that it's too slow/limited to do it well. It's fine for generating MIDI messages or control voltages (via a DAC, generally--the PWM outputs are not really sufficient). The point is to get familiar with programming microcontrollers, then move on to more complex/capable circuits.

If you do choose to go the Arduino route, there are a couple of libraries that you should be aware of right off the bat--the MIDI library from "Frankie" (who sometimes appears on this forum) and the Scheduler library by A. Brevig. Scheduler can be extended to be a great method of timing MIDI events.

I've written MIDI sequencers, clock dividers, rhythm generators, etc. using the Arduino (there's a movie clip in the FractalSynth thread of a four-channel MIDI sequencer I built around an Arduino and a VS1053 general MIDI chip). I've also tested real-time audio generation with the Arduino and found it quite limited.

As usual, it all depends on what you want to do.

Thanks,

Ole

[Rykhaard]