1 Dec
2009
1 Dec
'09
2:59 p.m.
On Tue, 1 Dec 2009 19:31:24 +0100 (CET)
karl(a)aspodata.se (Karl Hammar) wrote:
Very much agree, start simple and see how far we can push it.
Almost everyone has fast Ethernet, so lets stick with that for as long
as possible. It's easier to upgrade than downgrade!
I'll just go with the flow here :)
Pretty much ticks all the boxes for me.
--
Will J Godfrey
http://www.musically.me.uk
Say you have a poem and I have a tune.
Exchange them and we can both have a poem, a tune, and a song.
Patrick Shirkey:
At this stage, I'd just say whatever is easiest to work with. Shrinkage
and prettifying can come later!
Just to recap. These are the points that have
been discussed so far.
-------------------
Physical Size
-------------------
http://www.rittal.com/products/ArtikelDatenblatt.asp?ArtNr=1360500&lang…
600 mm x 600 mm x 350 mm
No, this is where I will put my system into. The actual "computer"
would be much smaller. I'm planning on something like
h: ~240, w: <200, d: < 200mm
But I don't think you should have to abide to that.
+++++ For the "soundcard" part, it might be more
useful if we instead talk
about interfaces.
With SPI, we are free to "attach" many different cpu-cards, it's just
clock, data out, data in, and a few chip select lines. And we can
potentially get 10-20 channels at cd quality.
With faster i/o, we can use the cpu's memory interface, or
some ordinary bus like pci or pci-x.
I'm not for pci or pci-x at this point, since that would be for me a
totally different project. Unless, of cause, someone else takes care
about the "bus" part, and I and others do the ad/da and analog part.
With spi or the memory bus, we cannot use an ordinary pc --- to bad.
But we could use the atmel network card mentioned a few lines below,
or the card I will eventually build, or some card someone else provides
source to.
PCI is on the way out and PCI-x seems to be rather fluid spi seems more
future-proof (in as much as anything can be)
---------------
Hardware
---------------
No decision has been made on the viability of designing a board from
scratch.
I will probably do everything from scratch, but given good and
sensible interfaces card<->card, one could possible use "any"
suitable cpucard.
- You have access to this board for
development/testing:
http://www.atmel.com/dyn/products/tools_card.asp?tool_id=4102
Ack.
The aim is to provide upto 8 audio i/o ports.
I don't think we should set an upper limit, instead it would be
interesting to see how many channels the system could support. I would say we try to make (input and output)
one desent channel, e.g. 16bits, 44.1/48kHz
one very good channel (if we manage), 24bits 192kHz, to try the limits
And then see how many we can fit into the system.
And, would that be an line input, or mic input channel, or
(software) switchable?
Initially line only, much easier to get a decent performance. Also
there are *lots* of mic preamps out there and everyone thinks theirs is
the best :)
Talking about, i/o. Would buttons, leds, relays,
linear and rotary
things (what is their name?), etc. be useful ?
KISS
Status LEDs would be good, but levels should be software controlled, so
no need for mechanical switches, Pots, Faders etc.
Connectivity
via Gigabit ethernet.
I don't think the atmel can do gigabit. Fast ethernet (100Mpbs),
is a more realistic choise unless we switch cpu.
--------------------------
Firmware/Software
--------------------------
The device will run Linux OS.
Audio data transfer will be via netjack using CELT compression.
Ack. -------------
Website
-------------
Need to define project vision, setup wiki, git-hub etc...
Ack.
I have some readme's at [2], and I will put all my other design files
there.
Here are some thoughts (extract from [3]):
The requirements are
. it should run linux
. developed with open source tools, current choise is gEDA
. expandable, you be able to easily add e.g. 8 D/A ports, 32 DIO etc.
preferably hotpluggable
. electrically rugged and EMC safe
. easy to make and build yoursalf, preferable double layer card
. the components should be available/purchable for a normal hardware hacker
. the should not cost to "much"
. no card edge connector
It seems that my "archetectural" choises are
. a single board computer
. a stackable system like pc104, pico-itxe or arduino
. a card frame system, either
- whith a backplane bus, like VME or CompactPCI
- or with the "backplane" on the cpu card, the motherboard style like ATX
The one which is easiest to expand is the card frame system with a backpland,
I will make my first try with that.