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  • Author Author: Former Member
  • Date Created: Date Created
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Cirrus Logic Audio Card 2015 Update

Former Member

Introduction to the Cirrus Logic Audio Card

With the launch of the Model B+ there was one significant, yet highly appreciated change which meant the existing audio card with the P5 pogo pins was no longer compatible with the Model B+. This is a mechanical limitation and unfortunately it wasn't possible to find a neat solution for the existing card.

To deliver the same audio experience we have updated and created a new audio card for Model B+, called the Cirrus Logic audio card. For anyone who may have missed it Wolfson Microelectronics was acquired by Cirrus Logic in the summer of 2014, hence the name change for the audio card.

This short blog introduces the new Cirrus logic audio card and provides some background on hardware and software developments.

 

Hardware

From a hardware perspective if it isn't broke then don’t mess with it - that was the simple approach we took to the hardware design.

So the updated audio card uses the same core components (WM5102 and WM8804) and has the same core architecture as the original card. From a features perspective there is no significant change however we have listened to the feedback and made some minor improvements. This is mainly around a back powering option, changing the expansion header to 2.54mm pitch, increasing the expansion header to make the unused GPIO pins from the Raspberry Pi accessible and adding the option to connect external stereo ECM microphones to the line input.  

This ensures that users can experience the same high quality audio experience using Model B / B+ or A+.

 

Please refer to the table on the main Cirrus Audio card community page, this provides a good summary of the feature comparison between cards.

 

The key take away on hardware is that the same primary functions remain on both audio cards with only minor changes in hardware design.

 

Software

From a software perspective we continue to update and improve.

Firstly the software for Model B and Model A+/B+ is exactly the same, automatic detection and pin mapping is included so there is no need for different compiled software kernels for the two boards. You can use the Cirrus 3.12 kernel image on either the Wolfson or Cirrus boards with no manual configuration or setup required.

 

What is currently available from a software perspective

  • A Raspbian image is available for download from the E14 community website using kernel 3.12. This will support the Model B,  B+ and A+ using either the Wolfson or Cirrus audio cards.
  • We have also published our source code for the 3.12 kernel on our own newly created github repository. You can find details and the source code here - https://github.com/CirrusLogic/rpi-linux/wiki

 

From the existing Raspberry Pi pull request we received good feedback on issues that users discovered, we have where possible addressed the issues and these are incorporated in the Cirrus github.


With regards to upstreaming into the Raspberry Pi kernel and in particular Kernel 3.12, we have encountered issues relative to how the kernel operates when the card is not connected, there are also issues which impact other audio cards. We have tried to find a solution to this but unfortunately the effort is not insignificant and reaches further than our own drivers. Therefore we are currently unable to support inclusion into the official Raspberry Pi 3.12 kernel.

We have discussed this with the maintainer and he is in support of this limitation and also with regards to our plans going forward.

 

What is our current plan going forward

Integration into the Raspberry pi kernel and in turn the Raspbian distribution remains our end goal. With the issues we have encountered integrating into the 3.12 kernel we are now focusing our efforts on integration to the latest kernel (3.18). The 3.18 kernel in particular adds support for device tree, this in turn provides support for add on modules and in particular will allow the issues with multiple I2S audio cards in 3.12 to be addressed. The Raspberry Pi kernel is planning to move from the current 3.12 kernel in the future so this provides an opportunity to add future support as part of the standard distribution.

 

 

There are now two audio cards available for the appropriate model of Raspberry Pi, both cards use the same software and most importantly both will deliver the same HD audio experience for both capture and playback.

 

We hope you find the new audio card a worthwhile addition to your Raspberry Pi Model B+ experience.

  • in reply to Former Member

    > My Cirrus audio card is sitting in a drawer waiting for the kernel update.

     

    I'm as frustrated as you are.  I went to Newark and bought the CirrusLogic audio card for use with an RPI 2 because Element 14 said they were compatible.  As we all now know, that wasn't a truthful statement.  The result is that I've got two pieces of hardware that won't work together because of the vaporware software problem.  I'm not at all happy about that.

     

    At this time it looks like Element14 is no longer advertising the card as being RPI 2 compatible, but they've failed to do that until after some of us have been injured by purchasing products that won't work together.

     

    Now the question is whether I should fall back, punt and return the incompatible hardware to Newark for a refund. Before taking the hit on shipping the incompatible hardware back to Newark, I tried the fall-back option of moving the CirrusAudio Card to an old Raspberry Pi Model B+ that already has a working system on it.  Because I'm not willing to lose all of the work that I've done customizing my RPi by purging my existing system and starting over from scratch using the Cirrus software image, I tried following Cirrus' build-your-own kernel and drivers tutorial that's mentioned in the CirrusLogic Audio Card Owner's Manual.  Unfortunately, the Cirrus kernel building wiki is fraught with sloppy errors and mistakes in the instructions that look like the result of careless authorship.  The process of building a working kernel while following Cirrus' instructions resulted in FAIL.  (I've been rolling my own linux kernels for well over a decade.)

     

    I feel like I've gone above and beyond the limits of what can be considered reasonable end-user effort to try to get the CirrusLogic Audio Card working.  As Georg Mill commented last month, "This should be the work of the engineers of Cirrus Logic. Don't do their job."

     

    John CL: Thanks for the tip about the IQaudIO Pi-DAC+.  Like Paul, I'll be tossing my CirrusLogic Audio Card into a drawer until the CirrusLogic engineers get around to doing their job.  I'm interested in buying something that actually works, and it sounds like the IQaudiO Pi-DAC+ is the answer.

  • Just piling on to this thread... Can we get a date when the drivers will work with the 3.18 kernel?  It is seriously misleading that element 14 says the board will work with the B+, but doesn't explicitly state that it won't work with the current (v2) B+.  My Cirrus audio card is sitting in a drawer waiting for the kernel update.

  • Still no word on when to expect a kernel that works with the RPi2 and the Cirrus Logic Audio Card?  I guess I might go with an IQaudIO Pi-DAC+.  I was planning to tryout Volumio and there is already a version that works with RPi2 and that audio card.

     

    I would be giving up the ability to use the Pi2 as an S/PDIF DAC, which would be kind of cool and which would have been possible with the Cirrus card.  Maybe later on, depending on how things progress...

  • in reply to timg73

    Agreed, as far as current state is concerned.  Hoping this can be addressed soon, or atleast to receive some information about timing.

  • in reply to Former Member

    Right.  So Paul's comment above is correct.