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low_rider
Joined: Dec 14, 2011 Posts: 14 Location: Israel
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Posted: Sat Jan 28, 2012 3:03 pm Post subject:
"simple" and available wavetable synth ic? |
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I've seen some stuff from Holtek but I am wondering if I might be missing something... |
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JovianPyx
Joined: Nov 20, 2007 Posts: 1988 Location: West Red Spot, Jupiter
Audio files: 224
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Posted: Sat Jan 28, 2012 5:12 pm Post subject:
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Well, there is dsPIC. You can get a 28 pin DIP version that has 128K instruction space (which can also store wave tables). Built in 16 bit stereo DAC up to 100 kHz.
Simple? Depends on your definition. Wavetable synthesis should be both simple and fun with a dsPIC in my opinion. _________________ FPGA, dsPIC and Fatman Synth Stuff
Time flies like a banana. Fruit flies when you're having fun. BTW, Do these genes make my ass look fat? corruptio optimi pessima
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low_rider
Joined: Dec 14, 2011 Posts: 14 Location: Israel
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Posted: Sun Jan 29, 2012 5:32 am Post subject:
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well, these are different solutions since any general purpose DSP IC would require implementing the synth. in code and actual audio conversion will require mode hardware such as a DAC. I was referring more to a ready-made IC that has most of the hardware already integrated, or maybe these are not very common? I wanted to save the time of constructing the LUTs of various instruments and to be honest I only implemented a DDS with simple waves and from the little I've read, it seems pretty complex to jump to the next level and generate (semi) realistic sounding tones of piano, guitar etc... |
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JovianPyx
Joined: Nov 20, 2007 Posts: 1988 Location: West Red Spot, Jupiter
Audio files: 224
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Posted: Sun Jan 29, 2012 5:50 am Post subject:
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In fact, a dsPIC can be had with 16 bit stereo DAC built in. multi input 14 bit ADC built in. 16K RAM built in. Program storage is built in. Very little external hardware is required to make a VCO from a dsPIC and it can be incorporated into a synth or if the goal is "small" the entire synth _could_ be put into a dsPIC. I know someone who is using a dsPIC on a "voice card" for a polysynth of 8 voices. This synth has one board for each voice where the dsPIC is the "VCO" for the system.
As far as wavetable synthesis goes, I am aware of no "vco chips" other than microprocessors. VCO chips are devices that are simply a VCO. That is, they generate some specific and fixed waveform(s) (not from a wavetable) using an external voltage to control the pitch. The most common output waveforms are sawtooth, square, triangle, sine and pulse and are generated using analog means. _________________ FPGA, dsPIC and Fatman Synth Stuff
Time flies like a banana. Fruit flies when you're having fun. BTW, Do these genes make my ass look fat? corruptio optimi pessima
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low_rider
Joined: Dec 14, 2011 Posts: 14 Location: Israel
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Posted: Sun Jan 29, 2012 10:29 am Post subject:
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I can see what you are saying, however the difference is that I am talking about a device that comes with readily available sounds of musical instruments + percussions vs. an instrument that generates basic wave shapes and these have to be combined, filtered etc... in order to create the sound of the instrument. |
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JovianPyx
Joined: Nov 20, 2007 Posts: 1988 Location: West Red Spot, Jupiter
Audio files: 224
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Posted: Sun Jan 29, 2012 10:36 am Post subject:
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Ok, yeah. Not aware of anything like a wavetable synth IC that is already set up and ready to go.
I know how to make a wavetable synth, but that requires several ICs or in my case, an FPGA or I could make a wavetable synth in a dsPIC (which would ultimately be a wavetable synth in a single IC), but that requires that one know how to and be willing to program it to make that happen. _________________ FPGA, dsPIC and Fatman Synth Stuff
Time flies like a banana. Fruit flies when you're having fun. BTW, Do these genes make my ass look fat? corruptio optimi pessima
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low_rider
Joined: Dec 14, 2011 Posts: 14 Location: Israel
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Posted: Sun Jan 29, 2012 10:56 am Post subject:
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don't get me wrong, I know that it is possible to implement using a DSP chip and if it will turn out to be the most simple way I will do it. I have used Atmel 8bit AVRs many times in the past, however stepping up to DSP MCU takes some learning and I need to have access to theoretical material as well since I never dealt with stuff like that before... |
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Boogdish
Joined: Sep 21, 2009 Posts: 122 Location: Bloomington, IN
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Posted: Sun Jan 29, 2012 12:18 pm Post subject:
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Jovian, I've been using 16F series PICs with assembly language for a little while now. If I was going to move to dsPICs is there a good book or website that would help me make the migration? Would I need to learn C?
Sorry if this is derailing the thread. |
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JovianPyx
Joined: Nov 20, 2007 Posts: 1988 Location: West Red Spot, Jupiter
Audio files: 224
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Posted: Sun Jan 29, 2012 12:44 pm Post subject:
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Heh, I don't know. I have a habit of just diving into stuff.
What I have is the complete set of PDF documents that describe in detail every function, every setting bit, etc. It's dry, but necessary reading.
Some of it you will find to be very much or just like earlier PICs. There are additional instructions for doing DSP. The PIC paradigm, however, is quite present. It will feel like a PIC's big brother.
I got the PDF documents from the MicroChip website. Everything you need is in them (like 40 or so files I think). There is also a programming guide/reference which describes how each instruction works. When I worked with some 8 bit PIC stuff, I just used the PDFs for it. For dsPIC, each describes one specific aspect, so if you don't care about serial ports, you don't need to read that one (right now). I would, however, recommend downloading and saving them all. Sorry, don't have the URL, but google will find "microchip dspic". For what it's worth, the dsPIC IC I'm playing with is dsPIC33FJ128GP802 (28 pin DIP). They were $5.xx in lots of 10.
It is possible to experiment with these chips either on solderless breadboard, or on stripboard and probably other ways. _________________ FPGA, dsPIC and Fatman Synth Stuff
Time flies like a banana. Fruit flies when you're having fun. BTW, Do these genes make my ass look fat? corruptio optimi pessima
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