I2S codec...

wildswan · 12:15 PM

Hi!
I'm trying to use I2S to interface an ARM micro to a PCM3060 codec using I2S. I'm just feeding it a ramp function using my code.

The trouble is that nothing comes out of the codec!

I don't have a logic analyser, so the best I can do is measure the clocks using my analog scope. There seems to be data on the SD line.

I'm using 2 x 16bit channels at 44100 with the MCU as master.

Here are my measured clocks:

MCK: 11.63 MHz
CK: 2.86 MHz (BCK)
WS: 45.45 kHz

So CK/WS = 62.9 and MCK/WS = 255.9

Do these clocks seem ok enough for the format? I'm trying to figure out if my codec's broken. It'll take me a few days to get my hands on a new one...I'd like to make sure it's not just me being dumb first!

sjalloq · 21st July 2010, 12:49 PM

That looks like it has been set up for 32-bit data.

2x32x44100 = 2.8224 MHz

Perhaps your BCK divider is wrong and needs to be x2.

wildswan · 21st July 2010, 01:36 PM

Hi sjalloq, indeed it was! Thanks for that. I fixed that value, so now the clocks are running at:

MCK: 11.63 MHz
CK: 1.46 MHz (BCK)
WS: 45.45 kHz

Still nothing from the codec. Just noticed offset of 1v on the + output and 1.5v on the - output.

I think it might be time to swap the codec after all....

wildswan · 23rd July 2010, 04:47 PM

Ok I just swapped the codec, to no avail :-( Still nothing out.

wildswan · 30th July 2010, 03:07 PM

Doh! Fixed the problem. Set the codec to hardware control to eliminate config options, then discovered i was sending 16 bit frames.

Set up microcontroller to send 24 bits in 32 bit frames and all is working! Thanks sjalloq

21st July 2010, 12:10 PM	#1
wildswan diyAudio Member Join Date: May 2006	I2S codec... Hi! I'm trying to use I2S to interface an ARM micro to a PCM3060 codec using I2S. I'm just feeding it a ramp function using my code. The trouble is that nothing comes out of the codec! I don't have a logic analyser, so the best I can do is measure the clocks using my analog scope. There seems to be data on the SD line. I'm using 2 x 16bit channels at 44100 with the MCU as master. Here are my measured clocks: MCK: 11.63 MHz CK: 2.86 MHz (BCK) WS: 45.45 kHz So CK/WS = 62.9 and MCK/WS = 255.9 Do these clocks seem ok enough for the format? I'm trying to figure out if my codec's broken. It'll take me a few days to get my hands on a new one...I'd like to make sure it's not just me being dumb first! Last edited by wildswan; 21st July 2010 at 12:15 PM. Reason: Mistakes!!!

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21st July 2010, 12:49 PM	#2
sjalloq diyAudio Member Join Date: Feb 2006 Location: Cambridge	That looks like it has been set up for 32-bit data. 2x32x44100 = 2.8224 MHz Perhaps your BCK divider is wrong and needs to be x2.

21st July 2010, 01:36 PM	#3
wildswan diyAudio Member Join Date: May 2006	Hi sjalloq, indeed it was! Thanks for that. I fixed that value, so now the clocks are running at: MCK: 11.63 MHz CK: 1.46 MHz (BCK) WS: 45.45 kHz Still nothing from the codec. Just noticed offset of 1v on the + output and 1.5v on the - output. I think it might be time to swap the codec after all....

23rd July 2010, 04:47 PM	#4
wildswan diyAudio Member Join Date: May 2006	Ok I just swapped the codec, to no avail :-( Still nothing out.

30th July 2010, 03:07 PM	#5
wildswan diyAudio Member Join Date: May 2006	Doh! Fixed the problem. Set the codec to hardware control to eliminate config options, then discovered i was sending 16 bit frames. Set up microcontroller to send 24 bits in 32 bit frames and all is working! Thanks sjalloq

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