padawan12 wrote:
Very true. The DC blockers in most s/c are going to be limiting. But there's no reason to assume people using Pd for more serious experimental applications won't use correct DAC hardware. I think its very exciting to see the emergence of Pd as an application for wider research in engineering, rapid prototyping etc and I applaud HC for thoroughness and attention to detail in the code. The beauty of sw over hw is extensibility, on a 64 bit system you could use this to position a radio telescope or whatever, far beyond the grain you'd ever get with 7bit microcontrollers.
The grain depends on the clock speed, not the bus width. MIDI is 7-bit, the micro is 8-bit, but nothing stops you from implementing a 64-bit register on a microcontroller, but you'd need 10 MIDI messages to fill it. As you say, it's all in the software. A 64-bit system just calculates faster, it doesn't do anything an 8-bit system can't, given enough time. A lot of PICs have a 10-bit PWM module built-in but it's only one channel. In software it's not too hard to make an 8-channel 16-bit PWM machine using an 8-bit microcontroller such as a PIC16F628 for less than the cost of a soundcard. The software method will have more jitter though unless you're careful to write code that executes in equal time for every possibility.
Martin
On Thu, 25 May 2006 13:24:16 -0400 Martin Peach martinrp@alcor.concordia.ca wrote:
Hans-Christoph Steiner wrote:
I should say, I forgot that PWM was used in synthesis some, so I was
thinking about electronics and control when I was talking about PWM.
That's why my PWM objects are tailored towards, but should work fine in the audio context too, unless you need the wandering DC offset.For controlling things with PWM I think you'll need to modify your sound card if you want DC output. AFAIK they all have capacitors on the ouput to block DC. I find it easier to program a PIC to do the PWM and talk to it from PD using MIDI continuous controller messages for 14-bit resolution, or noteon with velocity meaning pulsewidth for 7-bits.
Martin
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