Thursday, August 1, 2013

Cortex M4

New project! yep another one... Looking at building a Digital VCO, there are a couple of options here; Texas Instruments, Atmel & STMicroelectronics. I am also getting a different TI part that has the the Cortex M4F core which has floating point! Pros & Cons? Well the Atmel board has 1Mbyte of external RAM, which will be really good for my wavetable VCO. The ST chip can boot along at 168MHz. The TI one I am probably the most familiar with... There are other options out there as well, the Frescale parts (was Motorola) have a more accurate ADC but it is still really only about 14 bits really (the trouble with having sensitive analog parts on a digital substrate), the NXP parts are also quite neat in that they can come with multiple cores so one core can be monitoring the ADC values whilst the main core can be doing the calculations... What I hope to end up with is a couple of different VCO's. The wavetable one that gets the samples from an SD Card. A DX Voice one that uses FM and looks like a single voice of my DX7 but the frequency is 1V/octave. A harmonic oscillator that looks a bit like a cross between a Farlight Page 5 and a Buchla 148 Harmonic Oscillator, well at least Mark Verbos's take on it here. I would also like to do another Buchla favorite, the 259, with the whole gamut of dual modulation of phase, frequency, amplitude and timbre... All I need is a little more time...

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