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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.
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