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Old 13th July 2012, 04:14 PM   #51
phofman is offline phofman  Czech Republic
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Originally Posted by adelias View Post
The integrated ethernet interface is actually a USB to ethernet adapter.
Well, that is bad news indeed.
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Old 13th July 2012, 04:49 PM   #52
qusp is offline qusp  Australia
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seems like they really screwed the pooch here and its going to bite them big time. so many people would have been planning projects that you would think looking at the spec would be possible, but they have provided this 'functionality' with smoke and mirrors so it can say on the datasheet.

there will be a lot of angry geeks on the fora
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Old 13th July 2012, 05:45 PM   #53
adelias is offline adelias  Greece
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I will find some other use for the Raspberry Pi. I ordered a Mele A2000 to use instead.
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Old 6th November 2012, 07:43 PM   #54
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Originally Posted by oublie View Post
Hi folks,

Just an update, ive been following with some interest the evolution of the Rasberry Pi computer concept Raspberry Pi | An ARM GNU/Linux box for $25. Take a byte! Production has just started so my plan is to possibly use one of these little computer per speaker to act as an active crossover using a digital in connection split from my ht receiver and then using the processing power to run active crossovers and possibly some form of DRC signal processing. What do you think? Could it be done or am i asking too much from such a low end processor.
It can be done. Just get some cheap HT receiver with HDMI support to work as DAC and multi channel amplifier and connect RPi's HDMI out to it's HDMI in. Connect receivers HDMI output to some cheap HDMI monitor so you have the GUI running on RPi. Build an SPDIF receiver and connect it to RPi's I2S input - though unfortunately there aren't any ALSA drivers available for the I2S input yet, but there are people working on them. In the meantime you can play your music files from RPi's SD card or from USB HDD so you don't need SPDIF input at all. Take your time to study which Linux applications can be used to implement the crossover (brutefir or jconvolver for FIR,Zita-lrx crossover + other stuff here: http://kokkinizita.linuxaudio.org/li...ads/index.html, JACK for routing, media players etc.). Compile them for RPi and integrate the environment.

Last edited by mhelin; 6th November 2012 at 07:56 PM.
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Old 7th November 2012, 12:06 PM   #55
phofman is offline phofman  Czech Republic
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Originally Posted by mhelin View Post
Build an SPDIF receiver and connect it to RPi's I2S input
That would require switching the RPi soundcard integrated in the SoC to external clock generated by the SPDIF receiver. AFAIK the SoC allows such mode, the question is whether proper documentation is even available.
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Old 7th November 2012, 12:32 PM   #56
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Originally Posted by phofman View Post
That would require switching the RPi soundcard integrated in the SoC to external clock generated by the SPDIF receiver. AFAIK the SoC allows such mode, the question is whether proper documentation is even available.
That mode is propably buried inside VideoCore and not open source. Anyway, (software, possibly hardware, as some people are reported I2S interface outputting data using BCM2835 ALSA SoC drivers that come with RPi, so the I2S possibly is in sync with HDMI PCM out) sample rate conversion is one option.
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Old 7th November 2012, 01:11 PM   #57
phofman is offline phofman  Czech Republic
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The functionality is described on page 119 of http://www.raspberrypi.org/wp-conten...eripherals.pdf . Each I2S interface has optional clock direction (master/slave), feeding data asynchronously to the APB bus (similarly to PCI in regular PC). Most likely these registers are directly manipulated by the audio driver.

That means the SPDIF input is viable. Still you would need to do ASRC in software (e.g. using libsamplerate) between the incoming SPDIF clock and HDMI clock since I very doubt the HDMI output clock can be switched to slave.
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Old 8th November 2012, 08:06 AM   #58
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Originally Posted by phofman View Post
That means the SPDIF input is viable. Still you would need to do ASRC in software (e.g. using libsamplerate) between the incoming SPDIF clock and HDMI clock since I very doubt the HDMI output clock can be switched to slave.
Yes, you could propably take the optical out from the HDMI (AV) receiver and use it as sync source, though then the jitter may be a problem.
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Old 14th November 2012, 01:09 PM   #59
Neil_J is offline Neil_J  United States
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Originally Posted by mhelin View Post
That mode is propably buried inside VideoCore and not open source. Anyway, (software, possibly hardware, as some people are reported I2S interface outputting data using BCM2835 ALSA SoC drivers that come with RPi, so the I2S possibly is in sync with HDMI PCM out) sample rate conversion is one option.
The VideoCore stuff was open-sourced on October 24. Check the Raspberry Pi for more details.
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Old 14th November 2012, 01:48 PM   #60
phofman is offline phofman  Czech Republic
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The VideoCore stuff was open-sourced on October 24. Check the Raspberry Pi for more details.
From what I heard it is just a thin layer of API for the closed-source firmware.
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