TOPIC:

Looking over the new miniDAC board, there are headers for and SPDIF input at 0.5 volt consumer level. The datasheet states that this signal is passed through to the miniSHARC board as an imput, I'm assuming to pin 1 and a ground on header J2.

My question is how can I also get an SPDIF output? The manual states that on the miniSHARC, SPDIF out comes from pin 2 at 3.3v. However, this is part of the header that attaches to the miniDAC. Where would I find where this signal goes? Is there some pin on the miniDAC that has this SPDIF output signal? I need access to pin 2 on the miniSHARC board but the 30 pin ribbon cable covers it up. So where does it go and how can I gain this output? I would like to be able to have the option for full digital I/O when using the miniDAC board.

I have an SPDIF level converter from Twisted Pear. Where would I connect it to gain SPDIF outputs from a miniSHARC/miniDAC8 setup?

I have a related question: can you combine the miniSHARC, the miniDAC8, Digi-FP & Vol-FP? And run the 4x8 plugin? Then there would be digital input/output, plus the 8 analog outputs. And the plugin lets you choose between SPDIF input or I2S input. So maybe also connect a miniStreamer?

thomasjefferson wrote:

I have a related question: can you combine the miniSHARC, the miniDAC8, Digi-FP & Vol-FP? And run the 4x8 plugin? Then there would be digital input/output, plus the 8 analog outputs. And the plugin lets you choose between SPDIF input or I2S input. So maybe also connect a miniStreamer?

I can confirm that this will work, except that I am using the AN-FP instead of the Digi-FP. I just finished a project using an OpenDRC-AN with the miniSHARC processor, adding the miniDAC-8. The plugin works flawlessly in either 48kHz or 96kHz mode. The miniDAC-8 already has two pins for consumer level 0.5v SPDIF input. To gain an SPDIF output, all you would need is an SPDIF level converter to convert the 3.3V SPDIF signal on pin 2 of the J2 header on the miniSHARC or the miniDA (either one will work). If you haven't already purchased the Digi-FP, I would look at the AN-FP instead if you are interested in analog and digital connections...

To answer my own question, I received an email from devteam regarding the pinout on the SPDIF connector. They recommended soldering a wire from underneath the 30 pin connector. I don't know why I didn't think of that. Apparently when you connect the miniSHARC to the miniDAC8, the 30 pin connector on J2 covers up your SPDIF output on pin 2. That signal is not routed to any header on the MiniDAC8 and so you need to solder underneath the header a wire to carry the signal. You also need to convert 0.5v SPDIF consumer to what the miniSHARC expects (3.3v) in order to get it to work.

So what I have is a board that can do any combination of digital and analog I/O. According to the miniSHARC manual, the SPDIF output on pin 2 is tied to outputs 7 and 8 of the 4x8 plugin. So if I wanted to add even more channels I can send an SPDIF signal to another miniDSP processor directly and avoid an unnecessary digital/analog conversion.

Thanks for the update Sly and we look forward to pics of your final setup.. Maybe in the showcase section of this website?
As a new miniDSP member, you've been of great help to a wide range of users so once again thanks for sharing your knowledge and glad to have you as part of the community!

@thomasjefferson :
A little late for this, but if you look here
www.minidsp.com/forum/opendrc-projects/1...rc-stack-fir-project
your proposed setup with digi-fp etc. works fine.

@sly:
Nice work! Wish I'd seen this earlier; would have saved me some fishing around.

In my case I couldn't use SPDIF-TX since I wanted my first sharc to provide two 6144-tap FIR filters and only the OPENDRC2x2 plugin did that. It has no routing matrix though, so there was no way to map to channels 7 & 8 which, IIRC, feed SPDIF-TX.

Also, my minidac8/sharc stacked pair arrived without cables but with the boards stacked directly via long pins. This would provide an easier attachment point for SPDIF-TX. Now that I know what's posted here, perhaps I'll use it in the future if I can think of an application. I have plenty of room for another minisharc/minidac8, my stereo triamp only uses channels 1-6, and that second sharc uses MINISHARC4x8 plugin so I could map 7 & 8 to my inputs.

I wonder what the latency/delay would be on an unfiltered signal passed through one minisharc and feeding a second via SPDIF-TX/SPDIF-RX?