[L2Ork-dev] [newbie] Rapspi3 + CirrusLogicAudio card

[Ivica Ico Bukvic]

Hi Francois,

Welcome to the list. Please see my comments below.


On 5/10/2016 5:22 AM, francois.heslot at free.fr wrote:
> Hello,
>
> I have some newbie questions about L2ork on raspi3 + Wolfson audio card:
>
> 1) Does it run OK on a config with Rapspi3 + Cirrus Logic Audio card (element14, reference for audio card #2448312)?

I haven't tried it on RPi3. It works perfectly fine on 2. I seem to 
recall someone else running it on RPi3. I just got one the other day and 
will gladly test it and report once I have done so.

I also used external soundcard as I found one on RPi2 to be rather low 
quality. You can get small USB soundcards for < $7 on Amazon that work 
perfectly and offer also audio input (e.g. 
http://www.amazon.com/Sabrent-External-Adapter-Windows-AU-MMSA/dp/B00IRVQ0F8/ref=zg_bs_3015427011_1).

>
> 2) is pd running only as an interpreted language or is it possible to run it compiled on the raspi3 ?
> does a compiled version allow to reduce the delay/buff size ?

Currently only as interpreted language. You can run it headless which 
gets you rather close to something that resembles compiled approach. 
Either way, you have access to buffer options via startup flags.

>
> 3) Is it possible for l2ork and what would be the advantages of using a real-time version of the os on the raspi, using the config above ?

I haven't seen any in my experience. It seems vanilla kernel runs just 
fine. You will need to run pd(-l2ork) with sudo privileges if you wish 
to access GPIOs and I2C due to default OS permissions.

>
> 4) The GPIO is essentially swamped once the Cirrus logic audio card is plugged-in:
>
> 4.1 has anyone tested using the I2C lines by soldering additional wires to it, and used it successfully via L2ork for I/O control purposes (eg an additional I/O port, while the i2c lines are also eventualy used on some time slots by the audio card )? (and what are the i2c adresses already used by the audio card ?)

Pd-L2Ork comes prepackaged with unique gpio and i2c externals specially 
tailored to work with modern devices Lots-of-pots board 
(https://moderndevice.com/product/lots-of-pots-lop-board-for-raspberry-pi/) 
that provides easy access to all gpio pins and an onboard MCP3008 for 8 
analog inputs. The externals also support both hardware and software PWM 
(software is supported on all pins). These are further conveniently 
packaged in the K12 mode:

http://l2ork.music.vt.edu/main/wp-content/uploads/2014/03/pd-l2ork-k12-rpi-001.png
http://l2ork.music.vt.edu/main/wp-content/uploads/2014/03/pd-l2ork-k12-rpi-002.png
http://l2ork.music.vt.edu/main/wp-content/uploads/2014/03/pd-l2ork-k12-rpi-003.png

I would not use the i2c for the soundcard. Rather use the aforesaid USB 
soundcard (e.g. 
http://www.amazon.com/Sabrent-External-Adapter-Windows-AU-MMSA/dp/B00IRVQ0F8/ref=zg_bs_3015427011_1)

>   
> 4.2 is the L2ork control of an arduino still possible (does it requires gpio lines for fast response ? knowing that the (inherently slow) serial interface of the raspi is still accessible on a header of the audio card)
I think Arduino should work just fine by plugging into the USB port of 
the RPi. Pd-L2Ork provides easy to use K12 abstractions for Arduino 
interaction, as well.

Hope this helps!

>
> Thanks
>
> _______________________________________________
> L2Ork-dev mailing list
> L2Ork-dev at disis.music.vt.edu
> http://disis.music.vt.edu/listinfo/l2ork-dev
>