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Wiring Hardware >> Tangible computing >> 54 independent PWM outputs feasible?
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Message started by patrick_r on 02/05/11 at 21:23:46

Title: 54 independent PWM outputs feasible?
Post by patrick_r on 02/05/11 at 21:23:46
Hello all,

I'm intending to apply my Wiring (I assume it's a Rev.004) board for sending 54 PWM signals via the digital IOs.



As I understand this diagram, it's possible to use the analog outs 0-7 as digital outs. Adding these 8 to the 46 digital outs already available, my question for now is whether a Wiring Rev.004 can safely send software-based PWM on all these 54 pins individually and simultaneously? Is performance an issue doing this? The PWM values to be sent may jump very erratically (on purpose, that is).

Thanks for your thoughts, Pat

Title: Re: 54 independent PWM outputs feasible?
Post by barragan on 02/05/11 at 22:57:05
hi Pat, you can control all pins independently, it is hard to tell, because it all depends on the software PWM implementation. Are you working on a software pwm library? or are you planning to use something available? let me know.

Title: Re: 54 independent PWM outputs feasible?
Post by patrick_r on 02/06/11 at 00:21:50
Hi Hernando,

I'm not much of a coder (in terms of literal programming languages, I'm using vvvv for my projects), I'd have to start with what snippets or code I can find. I'm afraid that creating the PWM outside of Wiring in this case (my assumption) won't be fast/reliable enough. Would you suggest a serial or OSC based communication to send values to Wiring?

Thanks for your thoughts!
Pat

Title: Re: 54 independent PWM outputs feasible?
Post by barragan on 02/06/11 at 08:18:02
yes, Firmata is a library included with Wiring to send/receive data to/from wiring, it could also be done just using regular Serial communication, there is a plug-in for vvvv communicate with Wiring or Arduino http://vvvv.org/forum/firmata-plugin
Load the Firmata sketch into Wiring which is just a firmware that prepares the board to receive requests from other software via Serial. Be aware that if you are going to use Serial communication pins 32 and 33 won't be available as digital pins, since those are used for Serial communication RX/TX respectively.

Title: Re: 54 independent PWM outputs feasible?
Post by patrick_r on 02/06/11 at 15:23:13
The Firmata vvvv plug-in has been made for the Arduino, do you think it works with Wiring out of the box? I'm still researching hard on the electrical side of this piece, it depends on whether I'll be forced to apply a custom made interface producing PWM signals which are used to dimm 54 12V lines or if Wiring can be used with a less complicated/costly solution to do that.

From your answer I guess that I'll have to see for myself whether out-of-the-board software PWM performance on all pins (except 32 & 33) will be sufficient.
I'd rather like to have software based PWM on-board with the additional benefit of having two more pins to work with. What kind of communication can be used in this case, OSC or ?

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