DIY PC audio interface

[Rochey]

[quote author="pilo"]
@rochey
How much is it for the ref board? the Dice II chip seems to be a good one! I looked at it abot one years ago, but it was on TCelectronic website! I didn't know wavefront made one too??!!?? on tcelectronic website they say that it's avalaible in BGA and QFP package, none of it can be solder by us?[/quote]

I don't know about the cost. I'm more intersted in the BOM and Schematic to be honest

I don't work for TC - I have no ideas on costs. What I can tell you is that Wavefront Semi are the worldwide distributor for the device. TC Technologies have the techie brains, wavefront are good salesmen :grin:

For now, according to my source in TC, the device will only come in BGA. The device you're referring to may have been the Dice 1.

I still think a custom board for us group dIY'ers is possible, but we will need to use all the knowledge within this group to put it together. I have _no_ idea where to begin with laying out BGA devices
I get the feeling that BGA = at least 4 layers. Which isn't the end of the world, but it certainly hikes the cost of the PCB. I wouldn't be suprised if each card ended up costing close to 30 Euro's each + components and assembly.

There's a long way to go yet though. I personally feel we should split the project in 2 (analogue side (ADC/DAC) and Digital Interface. Anyone here have the skills to help with the digital side?

 

[Kev]

[quote author="pilo"]Making a pci is not a good idea, I think , because PCI is going to disappear, and making only a few piece of the card will cost a lot of money.[/quote]

I can't bring much to the table here but I do agree with this. Firewire must be on top of the list as has been said.

I'd still love to see an Ethernet style solution. The same goes for MIDI and other general Keyboard stuff. The versatility of the Ethernet port just makes sense to me. Good speed and good distance, it would make life very easy.

 

[pilo]

I was looking at http://www.opencores.org project, and there's already an ethernet interface and an I2S one ready... the firewire is still under progress... I think fpga can be a better idea than DICE II chip because it's more diyer friendly... but if we can get "cheap" board with DICE II, then, why not :wink:
If there's someone here who can give me links, book ref (I'm french but I can read english), I really want to learn more about fpga!

I personally feel we should split ...ave the skills to help with the digital side?
yes!!! there's good analog stuff here

 

[tmbg]

Like I said, I've got some DIY fpga experience... fpga isnt really all that hard.

 

[pilo]

Like I said, I've got some DIY fpga experience... fpga isnt really all that hard.

so...let's go? :grin:
the small fpga board from fpga4fun seems to be good to start.. (I saw the one you talked about before, but maybe it will be harder to merge it with adc and dac?)

 

[ikiru]

I've been following this topic with great interest. I am simply amazed. Although I have no technical additions, other than to say that firewire and ethernet seem like the ideal solutions(I'm a laptop guy who currently uses firewire). I think the driver issue, is something that we could possible collaborate with other communities, specifically the open source community which is teeming with talented programmers(just like this place is choc a block full of audio genius). I think the idea of opensource HARDWARE would probably inspire some outside contributions in the driver support area. All that is needed is a web page describing the project, goals , problems , solutions etc and then getting a little publicity via slashdot.

my two cents,

jay

 

[Rochey]

I'm all up for an ethernet system - as long as windows/mac drivers can be made with any ethernet device.
What I'm trying to say, is that regardless of which port ethernet card you plug it into, you can still bring the data straight into windows.

I consider it vital that we can connect this interface into almost any modern computer (or add an easy to find pci card). Most computers have ethernet ports and 1394 ports.

Ideally, something laptop users already have would be nice. A high quality portable system would be a*

Let's keep brainstorming this.

Cheers

R

 

[mcs]

[quote author="pilo"]@mcs
mmmm can be an interesting things to do maybe I have a second ethernet card here, but I don't know how much time it will take to try to write an alsa driver for it... and I don't know where to start lol but as the ethernet driver I use is open source, maybe it's doable?[/quote]
You should write a driver that interfaces with the network stack of the OS - not the Ethernet chip itself. That way you don't have to rely on a certain Ethernet chip (or bus standard).

Best regards,

Mikkel C. Simonsen

 

[Rochey]

doesn't that introduce latency (as it has to go through the windows networking stack?)

 

[tmbg]

I've been thinking and thinking... and I'm coming to the conclusion that ethernet is going to be non-ideal :/

There's no reasonable way to do layer1 comms. Rochey, you're right, layer3 will suck too much.

Possibly we could do something with layer2, but it's still gonna require a buttpile of special drivers to make work, and even then will be hackish.

Ethernet isn't designed to be a 'realtime' comms system... it's designed to be a 'keep sending til they get it' sort of thing.

I still like MADI... someone buy me an RME HDSP-MADI!

Seriously, if we tried hard enough, we could make a MADI PCI card.

 

[tmbg]

There is an open source PCI bridge core... if we could make a MADI to Wishbone SoC bridge in VHDL, then we could use the existing SoC to PCI bridge and fab a card

 

[mcs]

[quote author="Rochey"]doesn't that introduce latency (as it has to go through the windows networking stack?)[/quote]
You don't actually go trough the networking stack. You read and write Ethernet packets directly. But rather than having to create a driver for each Ethernet chip, you just use the systems existing driver.

That way you get full speed and control, but much fewer problems :wink:

Best regards,

Mikkel C. Simonsen

 

[mcs]

[quote author="tmbg"]it's designed to be a 'keep sending til they get it' sort of thing.[/quote]
Ethernet was designed to deal with bad links and collisions etc., which is why you need a dedicated link. With a dedicated link every packet you send will make it to the destination without any delays (unless you use the mentioned RTL8139 :grin.

Best regards,

Mikkel C. Simonsen

 

[Rochey]

I've had a quick look at TI (duh... i always look there first). Maybe this device could be used as part of the link to the PCI bus?

http://focus.ti.com/docs/prod/folders/print/pci2040.html

I haven't read the dsheet yet, and need to understand a little better how it can be used. You guys know a lot more about these things (that's obvious already)

let me know what you think

Cheers

r

 

[mcs]

[quote author="Rochey"]Maybe this device could be used as part of the link to the PCI bus?

http://focus.ti.com/docs/prod/folders/print/pci2040.html[/quote]
Don't you think it's obsolete by now? Look at the data of the datasheet: 09 Jul 1909 :green:

Best regards,

Mikkel C. Simonsen

 

[Rochey]

 

[tmbg]

rochey, I just glanced at it, but I'd be willing to bet that it's not nearly enough throughput for something like we want.

 

[Rochey]

cool - no problemmo, was just having a quick look.

I was looking for a Non-FPGA solution - as it may be easier to interface.

Cheers

R

 

[tmbg]

easier to interface? or easier to build...

Beautiful thing about an FPGA solution is, once it's laid out and you get through the hell of getting the power requirements how they need to be, an FPGA can be anydamnthing you want. An FPGA PCI card could be a generic computer widgeter - slap this front end on it and it's a multi-adat. This one makes it MADI. This one is 24 channels of mic preamps... etc

 

[Rochey]

agreed!

It does sound v.good to me.

Okay -- so we have 3 options then (from this discussion)

1. PCI Interface - based on an FPGA core
2. PCI Interface - based on a PCI IC + interface
3. Firewire interface using Bridgco or Dice II

If we make this as modular as possible, we should be able to keep the converter section, and connect it to either a PCI card or the Firewire card, should the need arise.

Could an FPGA solution provide i2s and MADI on different pins?

Also, does anyone have any idea how we could get the development underway (in terms of FPGA and Windows Software?)

Cheers

R