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?

Hi,

Here is the KiCAD file that I used.  You may want to add to it,  feel free!  And if you are going to get some made with gold plated pads for the pogo connector, please let me know  ..... I would like to buy a couple if possible

Regards

John

Hi,

Here is the KiCAD file that I used.  You may want to add to it,  feel free!  And if you are going to get some made with gold plated pads for the pogo connector, please let me know  ..... I would like to buy a couple if possible

Regards

John

Postscript:-  I cannot post the file directly, forum rules.  If you pass a private message with an email address, I will send it straight to you

Hi John   I can't  send you a  private message ...we must be  connected first 

Best Regards 

John , follow also me 

Hello Athanasios (and others)

Producing printed circuit boards is certainly possible (and I have spoken to the fabricators), but I will need to add to the design I published some time ago.  I am putting this message out to the community in order to see what I should add to the design.  Hias has already suggested that the board should be larger so that it can support the wolfson.  But are there other useful things I should try and incorporate? I guarantee nothing, but suggestions are welcome!

Hi John

At first, I would like to thank you for your help

Your prototype board meets Hias, hardware modifications, I have tested it also and works perfectly. 

So why not to move forward with some printed circuit boards for test

Remain the problem with the CAD layout to generate the Gerber

All the best

Some basic things to add to the pcb would be a .1" pin header with any available GPIO pins (not being used by the Wolfson card), the I2C bus, and the UART.  Also a parallel row of ground pins and several 3.3V  and 5V pins.

I use something like added onto the Cirrus card for indicator LEDs, a temperature sensor, a shutdown button,  RTC via I2C and GPS via UART.  A low noise LDO to convert the 5V to a clean 3.3V (or whatever voltage) for a preamp or something might come in handy for some uses.

Hi Spambake,

Very reasonable suggestions, many thanks.  The biggest problem with a 0.1 header would be that the board will need to be larger than the wolfson (which sits above it) in order to give access to the pins.  This would mean that the overall "footprint" will be greater than the raspberry beneath ..... not a problem in some instances. But when space is limited?  What do you (and others) think?

The obvious thing to do would be to reproduce almost all of the 40 way header (including the gpio used by the wolfson) outwards  (giving access, eg, to I2C...... leaving the covered space of the PCB (beneath the Wolfson) unused.  A low noise LDO? maybe?  But in my limited experience getting a really low noise power supply it would be best to source from other than the raspberry.

I had thought of an uncommited array of 0.1" pitch holes for prototyping,  but that rather shows my age!  Or some useful I2C device  .... but what?

Athanasios

How do you feel about adding a 40 way header to allow other connections? (Sadly that would not allow  stacking of further cards).  I am in two minds about whether to complicate the design (with extra risk),  but when the boards cost around 12 euros each (in small quantities) , plus VAT and delivery, it seems a shame to waste the board space?

Hi John,

I believe that there is a way that you can program the ADSP2 to your desires.

The tools for creating your own DSP software are available from Cirrus Logic (WISCE), and the compiler is from Synopsis (Target Compiler Technologies) (Chess Development Environment).

Depending upon which specific DSP (Smart Codec) you have from Cirrus, you may be able to obtain a development board for your specific needs and experiment with your own code development on the DSP and implement all the fancy processing you desire.

There is a learning curve, but once you get over the early part, you will be up and running.

Best regards,

David

David,

Many thanks for this tip.  I have used the WISCE software quite extensively.  It provides a means of setting parameters in the "static" part of the digital core and also (if I remember correctly) uploading soft/firmware into the 5102, but does not, as far as I am aware, allow development of the DSP code.  So your tip for Synopsis is useful, and I will follow it up.  Wolfson (who were brought out by Cirrus) called there DSP core the ADSP2, but there are several clues that it is a brought in design   ...... but exactly which is less clear!

The main clues in the 5102 manual are

Program memory      10_0000h to 10_5FFFh (24576 registers)      8192 x 40-bit words

Coefficient memory      18_0000h to 18_07FFh (2048 registers)      1024 x 24-bit words

X Data memory           19_0000h to 19_47FFh (18432 registers)      9216 x 24-bit words

Y Data memory           1A_8000h to 1A_97FFh (6144 registers)      3072 x 24-bit words

So the data memories correspond to the ADC and DAC width (but I guess the core will run at higher precision to allow multiply etc)

Just noticed there is a JTAG interface to the core, but whether I have the time to hack ....

I also have some stock firmware images for the 5102 DSP, which might also provide clues as to whether I am on the right track. 

If I make progress I will report back here, but my life is pretty busy at the moment, so it may not be very soon.

Regardless, thanks again  .... the prospect of developing a FIR filter still appeals to me

David,

Many thanks for this tip.  I have used the WISCE software quite extensively.  It provides a means of setting parameters in the "static" part of the digital core and also (if I remember correctly) uploading soft/firmware into the 5102, but does not, as far as I am aware, allow development of the DSP code.  So your tip for Synopsis is useful, and I will follow it up.  Wolfson (who were brought out by Cirrus) called there DSP core the ADSP2, but there are several clues that it is a brought in design   ...... but exactly which is less clear!

The main clues in the 5102 manual are

Program memory      10_0000h to 10_5FFFh (24576 registers)      8192 x 40-bit words

Coefficient memory      18_0000h to 18_07FFh (2048 registers)      1024 x 24-bit words

X Data memory           19_0000h to 19_47FFh (18432 registers)      9216 x 24-bit words

Y Data memory           1A_8000h to 1A_97FFh (6144 registers)      3072 x 24-bit words

So the data memories correspond to the ADC and DAC width (but I guess the core will run at higher precision to allow multiply etc)

Just noticed there is a JTAG interface to the core, but whether I have the time to hack ....

I also have some stock firmware images for the 5102 DSP, which might also provide clues as to whether I am on the right track. 

If I make progress I will report back here, but my life is pretty busy at the moment, so it may not be very soon.

Regardless, thanks again  .... the prospect of developing a FIR filter still appeals to me