Products Mentioned

ADAU1761 Production
The ADAU1761 is a low power, stereo audio codec with integrated digital audio processing that supports stereo 48 kHz record and playback at 14 mW from...
Datasheet
ADAU1761 on Analog.com

Associated Drivers

ADMP521 Obsolete
Analog Devices has sold its MEMS Microphone product line to InvenSense. Please visit the InvenSense ADMP521 product page for all technical support and...
ADMP521 on Analog.com

Thread Details

  • State Verified Answer
  • Replies 4 replies
  • Subscribers 72 subscribers
  • Views 974 views
  • Users 0 members are here
Options 

        

            Post
             Go back to editing
        

    

    


    

    









		


















	
	
			
	
			
		
	
	
		

	    
	    
	    		
Why is the digital mic mono'ed on my 1761Eval?

		
	
				

			

									
					    garygru
					
							

            
            			
				
									
											
			
			
				
			
			
			    	
			                    
                
				                on Jun 26, 2013 
				
			
			
		

		
		                     
				
        		

		    
		    		    
		    			

			    
Hi there, 

 
I'm using an EVAL-ADAU1X61EBZ Board with one(!) digital Mic ADPM521 on a Flex board. When plugging this mic onto the header J4 the signal is routed to both DSP Core inputs 0 and 1 although I can't find any mixing or input routing settings which I can blame for. It makes no difference if I choose L or R input (L/R Sel Hi/Lo). I also tried this ADAU1761_DigitalMicInToDAC.dspproj which I found somewhere here. 

 
When disabling left or right ADC, I still hear the input on the opposite ear (e.g. mic on input L, left ADC disabled => still hearable on right ear). 

 
Does it work as expected only when using two mics?

 
thanks,

 
Gary

			

			
									
		                             
                        

    

                                            
                 Audio Signal Processors
                
                                                    
                 SigmaDSP Audio Processors
                
                                                    
                 adau1761
                
                                                    
                 SigmaDSP
                
                                                    
                 admp521
                
                                
            

    
    
		


				
				        
        		

			
						
									
												
			
			
                        
                                    
                        
                        
                        
            
			            
						
						
			
			
			
			
		


        
        
        
    
					

			





















	

	

					



			








	
	
	
	



Parents
	
    
	

  • 
	
    



	
			
		
	



    
	
    
		
    
							
					
    
		
    
		    
		    		    
			
				
									
							        
			
			
			
    •  Analog Employees  
    
            
						
                            
            
            				
            
                on Jun 27, 2013 4:48 PM
            
            
						
			            		
    
		
										0
					
	
    

		
		
    
		
    
                                
                                                            
    
					
    When only one PDM microphone is connected to a codec input, the same data will be present on both the right and left channels of the PDM data stream. So, the codec's input will read identical stereo data channels. If you're disabling one of the ADCs in the ADAU1761, first make sure that you're disabling the digital circuitry and not just the analog circuits, which don't have any effect on the PDM data inputs. After disabling one of the ADCs, if you still hear identical data in both the left and right channels, the cause is probably in the signal routing in the codec. 
    
 
    If you have further questions about getting this to work, it might be helpful if you can attach the SigmaStudio project with which you're working.
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
				
						
						
				
				
		
		
    
			
		
    
	
    

    

    • 

	




Reply

    


  • 
	
    



	
			
		
	



    
	
    
		
    
							
					
    
		
    
		    
		    		    
			
				
									
							        
			
			
			
    •  Analog Employees  
    
            
						
                            
            
            				
            
                on Jun 27, 2013 4:48 PM
            
            
						
			            		
    
		
										0
					
	
    

		
		
    
		
    
                                
                                                            
    
					
    When only one PDM microphone is connected to a codec input, the same data will be present on both the right and left channels of the PDM data stream. So, the codec's input will read identical stereo data channels. If you're disabling one of the ADCs in the ADAU1761, first make sure that you're disabling the digital circuitry and not just the analog circuits, which don't have any effect on the PDM data inputs. After disabling one of the ADCs, if you still hear identical data in both the left and right channels, the cause is probably in the signal routing in the codec. 
    
 
    If you have further questions about getting this to work, it might be helpful if you can attach the SigmaStudio project with which you're working.
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
				
						
						
				
				
		
		
    
			
		
    
	
    

    

    • 





Children
	
No Data


		
			








		

		

			
    
				
  • 
					
												
						
						
						
						
						
						
						

																										
						
						

					
					
					
				
    •