New reworked driver for Wolfson/Cirrus Logic audio card

Hias,

A huge thank-you for all the work you've put into supporting the Cirrus Audio card.  Until now I've been using your kernel packages, and have just got round to trying the latest official 4.9 kernel which is also working very nicely.  It's a real shame that the Cirrus card has (or appears to have) gone out of production just when the software support became so good.  The older Wolfson cards are still available, so perhaps I'll get a couple and try modifying them to fit a 40-pin header.  Anyway, thanks again for everything you've done.  I really do appreciate it.

Tim

The Cirrus Card does seem to be out of stock everywhere - what a shame.  I just started working on an alternative ultrasound sensistive microphone, since the electret type I was using has been out of production for years and is now virtually impossible to get hold of.

What other options are there for recording audio at 192kHz with the Raspberry Pi?

And herewith the revised pcb

Hi John - thanks for the update.

Now all I have to do is find the elusive R39.  I only had a quick look last night.

Now all I have to do is find the elusive R39. I only had a quick look last night.

 

It's on the bottom side of the PCB, near the mounting hole.

so long,

Hias

Hias and John,

I got my "Frankenson" sound card working with a Pi2 .

I didn't de-solder the pogo pins.  I found a cover that fits over them nicely - made from a UK 3-pin mains plug protector that all new electrical devices come with.  I cut the end off the Earth pin end of the protector.  It fits neatly onto the pogo pins.  Once the Wolfson card is attached to the Pi, the cover is held nicely in place, and stops them shorting on anything on the Pi.

Here's the pogo cover made from a plug protector:

Thanks for your help with this neat hack.

Hystrix

Bravo, I like it.  One of the positive british traits that, improvisation.

I knew UK plugs would prove better one day .... It has only taken 60 years  ..... Ironically I cut the last one off my appliances only this week.

More seriously, note that there is a wee bit of strain introduced by the pin protector, perhaps raise the Wolfson card a millimetre to compensate.

I have just made the mark 1 piggy back board, so if I can get the single sided version to work, expect photos of that too.  It's good to see an active community

Ha!  I knew someone would mention the strain caused by the pogo pin protector.    This was an early photo - I actually trimmed off some more of the plastic on the left-hand side.  You can see the black header is catching on it in the photo - it's much better now.

My only concern is whether the springs in the pogo pins will eventually start to push the audio card off the header.  Time will tell.  I may even file off some of the plastic from the bottom of the pin protector, so the springs aren't compressed as much.

I look foward to the photos of the piggy-back board.

I got my "Frankenson" sound card working with a Pi2 .

 

I didn't de-solder the pogo pins. I found a cover that fits over them nicely - made from a UK 3-pin mains plug protector that all new electrical devices come with. I cut the end off the Earth pin end of the protector. It fits neatly onto the pogo pins. Once the Wolfson card is attached to the Pi, the cover is held nicely in place, and stops them shorting on anything on the Pi.

That's looking really nice, well done! And I think the cap over the pogo pins is a rather clever idea!

so long,

Hias

All,

I promised an update on the piggy back card approach. Apologies for the delay, real world demands ...

First a photo

Herewith my observations

1)  Making the pcb at home is a pain for the following reasons.

1.     Drilling the board exactly (for the headers) is difficult.
2.      I can do only single sided boards and this approach demands "creativity" when installing the 26 pin header for the Wolfson. Plated through holes would be better/easier/stronger
3.     (and worst) the pads to receive the pogo connectors must be gold plated (So whilst my card works at the moment, I await the effects of O2)

So the board needs to be made professionally to be a good long term option  .... and that will mean 10 of them!

2) The Wolfson is well clear of the main board.  This is good for ventilation and for access to the ribbon cable connectors if you need them. It is bad in terms of mechanical support of the card.

3) It does offer a zero mod way of connecting the Wolfson to a pi 2/3

Overall I shall probably "sacrifice" a pi 3 and cut pin 12 off the Pi header and connect Wolfson direct to pi 3, ie not bother with a piggy back board .  It is a minor mod and will have probably no impact on any future project  ... and a pi is easier to source than these sound cards!  So, with the exception of not removing R39, I will probably follow the same route as others on the forum.   But if your project needs easy access to those ribbon sockets, the piggy back route is worth considering.

Good job I am a Brit (expat) and still have one of those mains plug shrouds!

Nice PCB!  If you are taking orders for a professionally made piggy-back board, put me down for one .

By the way, I emailed Cirrus Logic earlier in the week about the status of the Audio Card, because I assume that once the Wolfson Card stocks are depleted, we have no means of recording audio with a Pi at 192 kHz.

Hystrix,

thank you for those kind words.  No promises about the board, but Matthias rightly pointed out that the piggy back board should support the Wolfson card.  So do you have any feelings about how to use the extra board space? (Around 12cm2).  I really need a good digitally controlled attenuator, much better to run the Wolfson to full 24 bit accuracy,  but that is an output too high for most power amps..  I have a really nice design (not mine), based on relays .  Yes the clicky things! But it needs around 50cm2.

Yes.  I have a stock of 3 Wolfson cards at the moment, but I am thinking of getting a couple more. Perhaps we could persuade Cirrus to release the design into the public domain  .... and then we would have to whip enough enthusiasm  for a group build!  But I suspect that Cirrus would like to lose the design in favour of their own devices   ..... though I do note the existence of the wm8281 (datasheet Jan 2017),  which looks very much like an update of the WM5102 .... it might even be upward driver compatible. I note too that some linux kernels have been adapted

Hystrix,

thank you for those kind words.  No promises about the board, but Matthias rightly pointed out that the piggy back board should support the Wolfson card.  So do you have any feelings about how to use the extra board space? (Around 12cm2).  I really need a good digitally controlled attenuator, much better to run the Wolfson to full 24 bit accuracy,  but that is an output too high for most power amps..  I have a really nice design (not mine), based on relays .  Yes the clicky things! But it needs around 50cm2.

Yes.  I have a stock of 3 Wolfson cards at the moment, but I am thinking of getting a couple more. Perhaps we could persuade Cirrus to release the design into the public domain  .... and then we would have to whip enough enthusiasm  for a group build!  But I suspect that Cirrus would like to lose the design in favour of their own devices   ..... though I do note the existence of the wm8281 (datasheet Jan 2017),  which looks very much like an update of the WM5102 .... it might even be upward driver compatible. I note too that some linux kernels have been adapted