How to connect a Wolfson Audio Card to a Raspberry Pi 3 Model B

Question

Hello,

Please forgive this question from a newbie.

I recently bought a Raspberry Pi 3 Model B (v1.2) and a Wolfson Audio Card. I have fallen at the first hurdle, as I cannot connect the two together!

There is a section of 2x20 upright pins on the Raspberry Pi, a subset of which look like they should connect to the 13x2 holes of similar size on the Raspberry Pi. But I'm not clear at what end of the set of 20 pins to put the 13 holes!

On the Wolfson Audio Card, there are 8 downward connectors, which look as if they are to make contact with something on the card. I've read about P5 areas, but my card does not have a series of 8 contacts next to the upright pins.

Also, there is a tall screw pillar on the Wolfson Audio Card, but if lined up with the 2x20 pins, there is no corresponding hole on the Raspberry Pi.

My understanding from the site is that my Raspberry Pi 3 is the latest model, and that Wolfson Audio Card is compatible with any "Revision 2 Raspberry Pis onwards". Therefore surely it is compatible somehow?

I'm sure I'm missing something obvious!

Many thanks,

Paul

alweekes · Accepted Answer

I've detailed the process in a blog post: - https://alw-audio.co.uk/?p=605 It works very well...

hystrix · Answer

Unfortunately, the Wolfson Audio Card is not compatible with the Raspberry Pi 3B, as you have discovered. You need the Cirrus Logic Audio Card: https://www.element14.com/community/community/raspberry-pi/raspberry-pi-accessories/cirrus_logic_audio_card?ICID=wolfson-cirruslogic-section

The Wolfson Audio Card is compatible with Raspberry Pi 1 Revision 2 onwards. The "Revision 2" refers to Pi 1 versions.

psyj · Answer

I note that the Cirrus version (ie for the 40 pin connector Pis) is no longer available from Farnell (although a handful are still around bundled with early pi as kits)

I have brought the wolfson variant, of which Farnell have a shed load (which I guess they would be happy to clear away).

I too would like to connect it to a pi3 and I note the following.

Physical compatability is very good. Specifically the pogo connector for J5 does not interfer with the main board, although obviously a small sheet of isolating material needs to be installed.

The cut out on the daughter pcb gives access to the key remaining pins on the 40 way connector (33-40)

The only difference I note on the connections is that GPIO_A (feeding the 8804) and the BCLK have moved around. So the only hardware modification needed is to cut the track from pin 12 of the 26 pin connector. The freed track would go to pin 33 on the header and the pin itself connected to pogo connector 3.

The other connections would be 38 (tx) pogo 6, 40 (rx) pogo 5, 35 (frame) pogo 4

BUT BEFORE TRYING THIS MODIFICATION, has anybody else had success/failure with such an approach?

And of course there are still software problems to addess ....

psyj · Answer

Hi Boris,

Project still active, but pi 1 plus wolfson working so well that it has become interim system, for which I have to build a multichannel variable attenuator (Output levels on the Wolfson are huge). Once that is done, back to the pi3 version. I am after some info on whether the new pi3 kernels will still support the functions I need and how they tell the difference between a wolfson and a cirrus card

psyj · Answer

Danny,

did not spot your comment in this thread ..... I have been mis-using the driver thread for noting my progress (which you have recently looked at).

There is a way of connecting the Wolfson to the pi2/3 with no hardware modifications to either. There is a photo of my proof of concept over on the other discussion (page 11). Note my comments/reservations. If you do need/want to use several Wolfson cards, I'll happily have a small batch of adaptor cards made (professionally) for the both of us and share the cost with you. They will probably end up at around 7-8 euros each, but I really have not costed it up yet. I know you are also considering other options too .......

John

PS over on the other thread you will see that the driver software for the Cirrus and Wolfson are identical, thanks to Matthias