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by DoctorH
Mon Jul 14, 2014 10:03 am
Forum: General discussion
Topic: The Raspberry Pi Model B+ Q&A thread
Replies: 388
Views: 185645

Re: The Raspberry Pi Model B+ Q&A thread

PWM is still used to generate the audio output - but now there is a dedicated supply rail for audio (which means it's completely clear of digital cruft) and dedicated output driver. The output impedance is a lot less than the B, and the output DC blocking caps are now 47uF which makes 32-ohm headph...
by DoctorH
Mon Jul 14, 2014 9:55 am
Forum: General discussion
Topic: The Raspberry Pi Model B+ Q&A thread
Replies: 388
Views: 185645

Re: The Raspberry Pi Model B+ Q&A thread

ShiftPlusOne wrote:
DoctorH wrote:The Geek Gurl video in your blog post announcing the B+ mentions that the built-in audio is "improved". Is this correct?
That is correct, yes.
Details?

Still PWM but with improved SNR [if so: achieved how?]? Or a different output method?
by DoctorH
Mon Jul 14, 2014 9:38 am
Forum: General discussion
Topic: The Raspberry Pi Model B+ Q&A thread
Replies: 388
Views: 185645

Re: The Raspberry Pi Model B+ Q&A thread

The Geek Gurl video in your blog post announcing the B+ mentions that the built-in audio is "improved". Is this correct?
by DoctorH
Sun May 05, 2013 9:24 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: STICKY: The I2S sound thread.
Replies: 927
Views: 481380

Re: I2S: Anyone got it running?

Now there is time for hardware mod. Is there chance to get I2S on RPi revision 1 board? The schematic for revision 1 is here: http://www.raspberrypi.org/wp-content/uploads/2012/04/Raspberry-Pi-Schematics-R1.0.pdf On page 2 you will see that GPIO28 through 31 are brought out and connected to R8/R10,...
by DoctorH
Sun May 05, 2013 12:29 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: STICKY: The I2S sound thread.
Replies: 927
Views: 481380

Re: I2S: Anyone got it running? (answer is yes!)

Thank you! It think that is the best way to do it until the driver finds it's way into the distributions someday. Who gets to decide whether/when drivers like this get rolled in to the official distribution? Would you consider the driver sufficiently mature to put in requests to RaspBMC and OpenEle...
by DoctorH
Sat May 04, 2013 9:19 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: STICKY: The I2S sound thread.
Replies: 927
Views: 481380

Re: I2S: Anyone got it running? (answer is yes!)

How easy (or possible) is it to use this driver with XBMC distributions such as RaspBMC or OpenElec?

P.S. Phil and Florian, you rock. Thanks for making this work!
by DoctorH
Sat May 04, 2013 10:19 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: STICKY: The I2S sound thread.
Replies: 927
Views: 481380

Re: I2S: Anyone got it running?

Wavelength, you should find this wiki useful.
by DoctorH
Sat May 04, 2013 10:17 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: STICKY: The I2S sound thread.
Replies: 927
Views: 481380

Re: I2S: Anyone got it running?

koalo,

It is my understanding that the default functionality ("ALT0") of the GPIO pins exposed on header P5 is not I2S audio, and these pins need to be configured to their "ALT2" function. Presumably this is done in drivers such as yours?
by DoctorH
Tue Apr 23, 2013 4:01 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: STICKY: The I2S sound thread.
Replies: 927
Views: 481380

Re: I2S: Anyone got it running?

For maximum fidelity you will want to use an external clock with ultra-low jitter, and to re-clock all the signals coming out of the pi (pass the signals through an ECL flip-flop driven by the low-jitter clock). Phil, thank you for working on this driver. For entirely selfish reasons I hope you cont...

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