Question about sample rate of audio codec WM8731 on DE2

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But the demonstration provides the clock of 25 Mhz ( 50/2 AUD_XCK pin).

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It's divided by 4, not by 2. The output clock changes state every second pulse of the input clock. So the full cycle is every four incoming clock pulses. Simulate it for better understanding.

Also, as you can see in the table, it doesn't have to be 12.288 MHz. It can also be 18.432 MHz. It depends on the BOSR bit.

Instead of using a divided clock, you can use a PLL to get a clock closer to the nominal value.

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It's divided by 4, not by 2. The output clock changes state every second pulse of the input clock. So the full cycle is every four incoming clock pulses. Simulate it for better understanding.

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thank you, It is really divided by 4, I have misunderstood because of the name CLOCK_2.

Therefore the MCLK is 12.5 Mhz ~ 12.288 Mhz. It is clear now.

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Also, as you can see in the table, it doesn't have to be 12.288 MHz. It can also be 18.432 MHz. It depends on the BOSR bit.

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yes, in the demonstation, they set BOSR =0.

ROM= 16'h1000;		 //mclk

so, for the sample rate of 44.1 khz, i need to divide 50 mhz by 3 ( 16.667 mhz ~ 16.9344 mhz ) and set bosr = 1 ?

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Instead of using a divided clock, you can use a PLL to get a clock closer to the nominal value.

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Thank you for your suggestion.

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So, for the sample rate of 44.1 Khz, I need to divide 50 Mhz by 3 ( 16.667 Mhz ~ 16.9344 Mhz ) and set BOSR = 1 ?

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Yes, but you can't just divide a clock by 3 without violating duty cycle restrictions. You would need to use a PLL.

When using a PLL, set the wanted frequency in the PLL MegaWizard. The MegaWizard will take care of selecting the best multiplication/division.

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Yes, but you can't just divide a clock by 3 without violating duty cycle restrictions. You would need to use a PLL.

When using a PLL, set the wanted frequency in the PLL MegaWizard. The MegaWizard will take care of selecting the best multiplication/division.

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thank you very much. I will use PLL as you suggest.

>:D<

Hi guys , I'm trying to understand the audio demo example for the altera De2 that comes into the CD

I'm reading the datasheet from wolfson(wm8731). At moment I doesn't know how they are using the index in the ROM array.

ROM[0]= 16'h0c00; //power down

ROM[1]= 16'h0ec2; //master

ROM[2]= 16'h0838; //sound select

ROM[3]= 16'h1000; //mclk

ROM[4]= 16'h0017; //

ROM[5]= 16'h0217; //

ROM[6]= {8'h04,1'b0,vol[6:0]}; //

ROM[7]= {8'h06,1'b0,vol[6:0]}; //sound vol

//ROM[4]= 16'h1e00; //reset

ROM[`rom_size]= 16'h1201;//active

Can you explain me please? Thank you.

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Hi guys , I'm trying to understand the audio demo example for the altera De2 that comes into the CD

I'm reading the datasheet from wolfson(wm8731). At moment I doesn't know how they are using the index in the ROM array.

ROM[0]= 16'h0c00; //power down

ROM[1]= 16'h0ec2; //master

ROM[2]= 16'h0838; //sound select

ROM[3]= 16'h1000; //mclk

ROM[4]= 16'h0017; //

ROM[5]= 16'h0217; //

ROM[6]= {8'h04,1'b0,vol[6:0]}; //

ROM[7]= {8'h06,1'b0,vol[6:0]}; //sound vol

//ROM[4]= 16'h1e00; //reset

ROM[`rom_size]= 16'h1201;//active

Can you explain me please? Thank you.

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First and foremost you should understand the software control interface. one write sequence require 3 bytes : 7-bit slave address ( 0x34 ), 1write bit ( 0 ), 7-bit register address, followed by 9-bit data.

at page 46 of the datasheet, you could find Table 29:Mapping of Program Registers

ROM[0]= 16'h0c00; //power down , R6 : enable power for all modules

ROM[1]= 16'h0ec2; //master R7: used inverted BCLK, Master mode, I2S format, MSB-first left-1 justified

I believe you could easily understand the rest of the configuration.

After configuring WM8731, you need to activate it by this one

ROM[`rom_size]= 16'h1201;//active

btw, For the I2sound demonstration WM8731 is configured in the sidetone mode ( directly route from mic to headphone ). If you want to make the codec speak audio from PCM like wav file, you probably want to see the configuration in SDcard to music demonstration.

Hi Amigo, thank you for help me. Ive understand that example. Thank you.

But now I've buy a SD_CARD that I've formated with FAT16 format and I've copied one song.

But when I download the sof file to my board and I connected the speakers there's not sound played.

How I can test the hardware ??? Maybe I'm forgot something??

It's very strange, could you help me please ?? Again thank you so much.

Ok, I think I should test the SD_CARD first and then the sound codec, otherwise I work very well with the I2Sound. Any recomendation on this topic ?

Also I've a small curiosity.. What's the difference if I run the demo from I2sound, because it seems that the Line IN it's always connected with the LINE OUT?.

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Hi Amigo, thank you for help me. Ive understand that example. Thank you.

But now I've buy a SD_CARD that I've formated with FAT16 format and I've copied one song.

But when I download the sof file to my board and I connected the speakers there's not sound played.

How I can test the hardware ??? Maybe I'm forgot something??

It's very strange, could you help me please ?? Again thank you so much.

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SDCard to music demonstration using Nios II ( SOPC ). To make it work after downloading sof file, you need to use the program called altera_monitor_program to run NIOS II then music will come out :D.

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it seems that the Line IN it's always connected with the LINE OUT?.

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yes, it is

HI Amigo, thank you so much for asist me in this trouble.

I've followed these insctuction but the music is not playing.:(

1. I run under the nios console

nios2-configure-sof DE2_SD_CARD_AUDIO.sof

then I run the altera monitor and I select :

Configuration >> Configure system >> I select the PTF from the project,

I chosse cpu_0 processor and the .text and .data sections are in the epcs_controller .

I've search in all the project any code like C or ASM for play the waw but i doesn't found anything. (¿Do you choose any source file?) So, without selecting any file I had choosed

actions >> connector processor

Then I leave running the processor but nothing happends :S

The SD CARD was formated using mkdosfs, it's a 2gb from markvision

# mkdosfs -F 16 -R 1 /dev/sdc1.

Can you help me please?? Thank you