I don't recommend OMAP-L137 because of its poor Audio codec performance

Dear All,

I am a professional in digital field. We have bought 3 OMAP-L137 boards. We are going to work with Audio Codec AIC3106. However, its performance is very lower than that mentioned in datasheet. We used the default setting of the codec and board. I think the default setting of  a board primarily should give the best signal in terms of SNR. The setting of the audio codec registers are as follows: (the register values are in hexadecimal format)

Reg[0]=0                                                                        
Reg[1]=80                                                                       
Reg[2]=0                                                                        
Reg[3]=10                                                                       
Reg[4]=4                                                                        
Reg[5]=0                                                                        
Reg[6]=0                                                                        
Reg[7]=0                                                                        
Reg[8]=0                                                                        
Reg[9]=0                                                                        
Reg[10]=0                                                                       
Reg[11]=1                                                                       
Reg[12]=0                                                                       
Reg[13]=0                                                                       
Reg[14]=0                                                                       
Reg[15]=18                                                                      
Reg[16]=18                                                                      
Reg[17]=f                                                                       
Reg[18]=f0                                                                      
Reg[19]=40                                                                      
Reg[20]=78                                                                      
Reg[21]=78                                                                      
Reg[22]=40                                                                      
Reg[23]=78                                                                      
Reg[24]=78                                                                      
Reg[25]=0                                                                       
Reg[26]=0                                                                       
Reg[27]=fe                                                                      
Reg[28]=0                                                                       
Reg[29]=0                                                                       
Reg[30]=fe                                                                      
Reg[31]=0                                                                       
Reg[32]=18                                                                      
Reg[33]=18                                                                      
Reg[34]=0                                                                       
Reg[35]=0                                                                       
Reg[36]=0                                                                       
Reg[37]=0                                                                       
Reg[38]=0                                                                       
Reg[39]=0                                                                       
Reg[40]=0                                                                       
Reg[41]=0                                                                       
Reg[42]=6c                                                                      
Reg[43]=80                                                                      
Reg[44]=80                                                                      
Reg[45]=f                                                                       
Reg[46]=f                                                                       
Reg[47]=8f                                                                      
Reg[48]=0                                                                       
Reg[49]=0                                                                       
Reg[50]=0                                                                       
Reg[51]=c                                                                       
Reg[52]=f                                                                       
Reg[53]=f                                                                       
Reg[54]=8f                                                                      
Reg[55]=0                                                                       
Reg[56]=0                                                                       
Reg[57]=0                                                                       
Reg[58]=c                                                                       
Reg[59]=0                                                                       
Reg[60]=0                                                                       
Reg[61]=0                                                                       
Reg[62]=f                                                                       
Reg[63]=f                                                                       
Reg[64]=8f                                                                      
Reg[65]=c                                                                       
Reg[66]=0                                                                       
Reg[67]=0                                                                       
Reg[68]=0                                                                       
Reg[69]=f                                                                       
Reg[70]=f                                                                       
Reg[71]=8f                                                                      
Reg[72]=c                                                                       
Reg[73]=f                                                                       
Reg[74]=f                                                                       
Reg[75]=8f                                                                      
Reg[76]=f                                                                       
Reg[77]=f                                                                       
Reg[78]=8f                                                                      
Reg[79]=8                                                                       
Reg[80]=f                                                                       
Reg[81]=0                                                                       
Reg[82]=80                                                                      
Reg[83]=0                                                                       
Reg[84]=0                                                                       
Reg[85]=0                                                                       
Reg[86]=8                                                                       
Reg[87]=0                                                                       
Reg[88]=0                                                                       
Reg[89]=0                                                                       
Reg[90]=f                                                                       
Reg[91]=0                                                                       
Reg[92]=80                                                                      
Reg[93]=8                                                                       
Reg[94]=0                                                                       
Reg[95]=0                                                                       
Reg[96]=0                                                                       
Reg[97]=0                                                                       
Reg[98]=0                                                                       
Reg[99]=0                                                                       
Reg[100]=0                                                                      
Reg[101]=0                                                                      
Reg[102]=2                                                                      
Reg[103]=0                                                                      
Reg[104]=0                                                                      
Reg[105]=0                                                                      
Reg[106]=0                                                                      
Reg[107]=0                                                                      
Reg[108]=0                                                                      
Reg[109]=0       

I used a signal generator to generate a sinusoid signal shown in Figure 1. It is clean. Then, I used following instruction that captures from line in and plays on line out (ALSA driver):

arecord -d 20 -D 'hw:0,0' -r 96000 -f S32_LE -c 2 | aplay -D 'hw:0,0' -c 2

I saw the output by a scope. Figure 2 shows the result. The result is so noisy. Our analysis by Matlab shows that the SNR is about 50 db. This is really disappointing.

Figure 1

Figure 2

All three OMAP-L137 have the same mistake. I checked the different setting but the mistake was not solved. The SNR is vital for our application.

Please, help us on this issue.

Thanks,

Jack,