Parallella Community

Here's a video of me showing an existing audio application on the ARM cores running on Jack with interfaces connected over USB (all computing and screen is only Parallella):



T.

Very nice! Look forward to seeing what you do next. What are your plans for the Epiphany? Is there anything missing on the DSP library side or daughter card side for things to make the Parallella interesting as an audio platform?

Andreas

Great! Why don't you add a new category "Synthesizer" to the Parallella VerifiedPeripherals page?
http://elinux.org/Parallella_VerifiedPeripherals

Thus far there's no explicit sync construction, I wonder also about the granularity of letting the Epiphany do real-time computations: how much overhead does it cost to put some filter or other operation on the Epiphany, and how much effective bandwidth is there to get buffered data to and fro over the bus.

Also, suppose I have routines to feed an Epiphany core with buffered sound data, what's the overhead of "sync"ing a routine on it to run on that data, and how fast can I know in a Linux thread that it is finished ?

In the project setup, there was attention for the quick interface with the FPGA to the AIX. As it seems, only one particular DMA type operation comes to about 25% of that bandwidth, so that sure would be interesting improvement.

One of these days I'll again look into FPGA sources, to see how hard it is to get a third communication stream for SPI and DA convertor links, etc, for which a *cheap* breakout board would suit me (that preferably fits in this 1 HU 19 inch rack unit):



However, I think it may as well be interesting to use DSP slices from the FPGA for fast filters, and sinc (sin(x)/x)) type resampling operations, and to know what granularity and what type of operations would work good with the FPGA and the Epiphany I need to check sources and run bandwidth tests, which I'd prefer not to have to, even though the examples are good to have (and test).

Theo V.

Interesting...

Hi Theo

I wonder if you could maybe help me out with an alsa problem: viewtopic.php?f=13&t=1637

Cheers

Andy

Well, as it appears, alsa is a bit limited and some things are broken, like I have never been able to get any streaming going on with the HDMI TOS connections: it always opens, and then hangs.

i did do various alsa upgrades, and compiles, and a jack compile that, even though it was showing a low of errors and limitations, did get me to do some of the audio processing I wanted. I hope I saved the aptget, git and make history in some backup USB stick, because it got lost during one of the annoying SD card fails I had.

I don't know the particular problem you describe, I'll look into audio again later, I've been looking at some other things.

T.

Hi Theo,

Sorry missed your reply.

The issue I was having was caused by the dodgy usb on the Parallella.

Maybe you could help me with another, trying to run anything jack on the Parallella I get:

FATAL: cannot locate cpu MHz in /proc/cpuinfo

Looking around on the net this seems to be an issue with many arm linuxes, is this why you built jack?

Cheers

Andy