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by dariush
Sat Jun 23, 2012 6:59 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: STICKY: The I2S sound thread.
Replies: 838
Views: 345971

Re: I2S: Anyone got it running?

Gert van Loo wrote:Or you could solder a wire to one of the PCM/I2S pins going to the 'revision' resistors.
That's what I meant with modding the Pi.

cheers
Dariush
by dariush
Fri Jun 22, 2012 6:22 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: STICKY: The I2S sound thread.
Replies: 838
Views: 345971

Re: I2S: Anyone got it running?

Hi, I don't quite understand how I'd set the PCM_CLK correctly? All this bit twiddling is confusing me :? standard stereo audio 44.1 KHz @ 16bit would require 1,411,200Hz [is tht right?] any help would be appreciated! Cheers, Ears. The frequency depends on what you are going to do with the signal, a...
by dariush
Fri Jun 22, 2012 6:01 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: STICKY: The I2S sound thread.
Replies: 838
Views: 345971

Re: I2S: Anyone got it running?

What I understand from the code: *(clk+0x26) and *(clk+0x27) are the two registers given by Gert, 0x7E101098 and 0x7E10109C. The value " 0x5A000000 | 3<<12 | 1<<9 " translates to 01011010.00000000.00110010.00000000 in binary. So if we extract bits 23-12 we get the integer part: 00000000.0011 (3), a...
by dariush
Wed Jun 20, 2012 7:28 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: STICKY: The I2S sound thread.
Replies: 838
Views: 345971

Re: I2S: Anyone got it running?

Hi, Could you just clarify; do we need to remove resistors and solder onto the bare tracks to get to the I2S outputs? Cheers, Ears. You can access PCM_DOUT and PCM_CLK directly via the P1 connector (that is GPIO21 and GPIO18). Not PCM_FS or PCM_DIN, though. Those ones are not available (to the best ...
by dariush
Mon Jun 18, 2012 8:42 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: STICKY: The I2S sound thread.
Replies: 838
Views: 345971

Re: I2S: Anyone got it running?

Hi, Would it be possible to post your working code? sure! This code should set the frequency of PCM_CLK to 6.144MHz and output 0xA0A0A0A0 in a loop. The output on PCM_DOUT is correct, however the clock is somehow too high (about 6.4MHz). cheers Dariush // // output A0A0A0 on PCM_DOUT with about 6Mhz...
by dariush
Mon Jun 18, 2012 8:29 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: STICKY: The I2S sound thread.
Replies: 838
Views: 345971

Re: I2S: Anyone got it running?

-> PCM_CLK: seems to be the clock at which the I2S system is actually running (can be either PCM_MCLK or fed via GPIO18 from the outside). That is the PCM/I2S clock you just enabled. It controls the speed at which the PCM/I2S runs, provided you select the 'internal clock' mode Yep, your right! Nice...
by dariush
Sun Jun 17, 2012 3:00 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: STICKY: The I2S sound thread.
Replies: 838
Views: 345971

Re: I2S: Anyone got it running?

Hi Gert, thank you very much! That was it! Do you know how this clock relates to the clocks mentioned in the PCM/I2S chapter of the datasheet? The datasheet mentions three clocks : - The APB clock domain. (p.119) - PCM_CLK (p.120) - PCM_MCLK (p.120) My interpretation: -> PCM_CLK: seems to be the clo...
by dariush
Sat Jun 16, 2012 6:34 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: STICKY: The I2S sound thread.
Replies: 838
Views: 345971

Re: I2S: Anyone got it running?

Hi Gert,

thank you very much!

Yes, a disabled clock would probably explain this.

Looking forward hearing from you (don't worry, I'm not desperate enough to start fuzzing unknown registers ;)

cheers
Dariush
by dariush
Fri Jun 15, 2012 7:52 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: STICKY: The I2S sound thread.
Replies: 838
Views: 345971

STICKY: The I2S sound thread.

Hi, I'm currently experimenting with the I2S/PCM interface. (I know, PCM_FS isn't accessible as a GPIO on the RasberryPi, but PCM_CLK and PCM_DOUT are, which might be useful enough for certain use cases). However I'm having trouble getting the I2S system to work. Maybe I misread the datasheet. For s...

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