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Anyone interested in a small ADAT to I2S interface board?
« on: February 24, 2016, 10:22:15 AM »
Not sure if this is the right place for this, but I was thinking about making a simple ADAT to SPDIFformat converter for myself but then, as usual, the different ideas I had for it started getting away from the "simple" part.  I am mostly interested in this to interface my AD8000 to my DAW so I wasn't going to worry about SMUX or anything above 48K.  But I figured I would put it out there and see if anyone else might be interested in something that could be interfaced with whatever they might be building.  These would be based around the Wavefront chips because I have a healthy pile of them however the supply is limited. Theres a couple of options:

Easiest - I already have a board design and a prototype for a basic wavefront encoder/decoder with supplies and level shifters that uses a microcontroller to set modes.  It's small and just brings out all the clocks and data lines out to a header for interfacing with other things. but it's basically done and all I would have to do is order more PCBs if people want them.  because of the uC I wouldn't feel comfortable selling these as a kit because with being programmed properly they are useless.  but it would be a low parts count so it wouldn't be too much for me to assemble.

Moderate - Ideally I wanted a no-fuss ADAT to AES, AES to ADAT with external word clock.  this would be simple to design, but its a higher part count and since I hand assemble these, I'm not sure what the final cost would be, but I would totally be down for selling kits for these since there would be no uC or anything to program, everything would be hardware jumpers.  it would be all surface mount though so you would have to be comfortable with soldering down to 0603 resistors.  still only 48K though, keep that in mind.

Super duper - If there's enough interest to make it worth while, we could go all out with SMUX and a DSP for clock control and management.  This would be a reasonably complicated build and would take the most time (I do have a day job and a 1-year-old).  but its definitely possible.  I just don't think there would be enough interest in this.  The original idea of this is to keep things simple, and if you wanted something complicated RME makes a box that does all of this. 

Anyways... I have 4 of the "easy" PCBs.  I plan on keeping at least two for myself. Plenty of Wavefront parts.  even if you just wanted to buy some of those from me I'm open to it. 


Re: Anyone interested in a small ADAT to I2S interface board?
« Reply #1 on: March 02, 2016, 11:28:20 PM »
I have an interest in SPDIF to ADAT with SMUX.  Essentially I want to take 8 channels of 96k ADAT and route them to various SPDIF devices (or vice-versa).  Optionally, SRC would be good but mainly just divide/multiply by 2.  No tricky stuff like 96 to 44.1.


kxnz

Re: Anyone interested in a small ADAT to I2S interface board?
« Reply #2 on: March 31, 2016, 01:12:08 AM »
I'd definitely be interested in a small ADAT to I2S interface board and some of the ADAT encoder / decoder chips.  I'd like to bring some of my projects that involve high channel counts out to ADATs to be plugged into my audio interfaces / DAWs.  Your 'easiest' option sounds fine for what I'm looking at doing.

What microcontrollers are you using? I'm perfectly happy soldering / assembling / programming the boards.

Re: Anyone interested in a small ADAT to I2S interface board?
« Reply #3 on: April 14, 2016, 11:32:59 AM »
Wavefront chips don't use I2S format.  You can set the format to Left Justified or Right Justified by driving the correct pins HIGH or LOW (see AL1402 data sheet)

Most audio DAC support both formats, although some may require you to use a micro-controller to select one via programming the SPI/I2C bus.

To support SMUX, detect the SMUX status, then generate the faster audio clocks, re-arrange the decoded serial audio bit streams and transmit them to the audio DACs in sync with the new clocks.

Code: [Select]

Receive from AL1402
-------------------
Decoded serial audio bit streams in SMUX2 mode (4 channel of 88.2K/96K)
Master clock 11.2896MHz/12.288MHz
Bit clock 2.8224MHz/3.072MHz
Word clock 44.1KHz/48KHz
Word clock: RISE  FALL  RISE  FALL  RISE  FALL  RISE  FALL
            CH1#1 CH1#2 CH2#1 CH2#2 CH3#1 CH3#2 CH4#1 CH4#2

Decoded serial audio bit streams in SMUX4 mode (2 channel of 176.4K/192K)
Master clock 11.2896MHz/12.288MHz
Bit clock 2.8224MHz/3.072MHz
Word clock 44.1KHz/48KHz
Word clock: RISE  FALL  RISE  FALL  RISE  FALL  RISE  FALL
            CH1#1 CH1#2 CH1#3 CH1#4 CH2#1 CH2#2 CH2#3 CH2#4

Transmit to DAC
---------------
SMUX2 (4 channel of 88.2K/96K)
Master clock 22.5792MHz/24.576MHz
Bit clock 5.6448MHz/6.144MHz
Word clock 88.2KHz/96KHz
Word clock: RISE  FALL  RISE  FALL  RISE  FALL  RISE  FALL
            CH1#1 CH2#1 CH1#2 CH2#2 CH3#1 CH4#1 CH3#2 CH4#2

SMUX4 (2 channel of 176.4K/192K)
Master clock 22.5792MHz/24.576MHz
Bit clock 11.2896MHz/12.288MHz
Word clock 176.4KHz/192KHz
Word clock: RISE  FALL  RISE  FALL  RISE  FALL  RISE  FALL
            CH1#1 CH2#1 CH1#2 CH2#2 CH1#3 CH2#3 CH1#4 CH2#4


mhelin

Re: Anyone interested in a small ADAT to I2S interface board?
« Reply #4 on: May 18, 2016, 04:03:10 AM »
You could build an  ADAT to I2S interface with SMUX support easiest using the XMOS xCORE processors and software (using the available libraries and example applications).
Mikko

rkn80

Re: Anyone interested in a small ADAT to I2S interface board?
« Reply #5 on: May 29, 2016, 11:16:04 AM »
XMOS? Easiest? Did we see the same software stuff?

ka

Re: Anyone interested in a small ADAT to I2S interface board?
« Reply #6 on: January 18, 2017, 02:55:14 PM »
I am curious about the 'easiest' option... are you just bringing the 1402 outputs to a header? I am not sure, but I don't think the output of the 1402 is I2S format. In I2S the first data bit (MSB) happens 1 bit after the WCLK transition. I don't think the output of the 1402 has a 1-bit delay - the MSB is the first bit at the word clock change (according to the Wavefront data sheets). It would take some glue logic with a 1 bit delay to make the (4) 1402 outputs I2S format.

FYI, the 1402 is still being made by Coolaudio (V1402). The only vendor I know of that is selling them in small quantities is http://cabintechglobal.com.