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ADV7844 Recommended for New Designs
The ADV7844 is a high quality, single-chip, 4:1 multiplexed HDMI receiver and graphics digitizer with an integrated multiformat video decoder. The ADV7844...
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ADV7844 on Analog.com

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Inquiry regarding ADV7844 memory interface



		

			

									
					    Andrew.Choi
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Dec 11, 2023 
				
			
			
		
    

				
		
    
		    		    
		    
		    		      		            		        
    Category: Hardware
    
    		        		            		    
    Product Number:  adv7844 
    
    		        		    		    	
			
    HI ADI's
    

    

    

    One of my customers is producing a product using ADV7844 and is having an issue after changing the memory.
    

    

    Issue
    

    1. Dot noise occurs when S-Video or CVBS signal input
    

    2. The defect occurred after the SDRAM IC was changed.
    

        SDRAM IC manufacturer is the same, only DIE has changed (EtronTech EM6AA160TSC-5G -> EM6AA160TSE-5G)
    

    

    Question
    

    Is there any parameter in ADV7844 that can change the characteristics of the signal line connected to SDRAM?
    

    

    Thank you
    
									
			        
		
    

				
						
        

    
    Tags: 
                                            
                 Video Products
                
                                                    
                 hardware
                
                                                    
                 adv7844
                
                                                    
                 HDMI/DVI Receivers
                
                                                    
                 HDMI/DVI Devices
                
                                
            
    
    
    

		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    
















    
	
    
	
    
					



			








	
	
	
	



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      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Dec 12, 2023 8:41 AM
            
            
					
      
	
      

		
		
      
					
      Hi,
      

      We believe that the following things are already taken care of after changing the memory.
      

      You should be able to refer to ADV7842_External_Memory_Test_Rev0.pdf and ADV7842_Recommended_Settings_Rev2.0_241013.pdf.
      

      The DQML and DQMH pins of SDRAM were grounded properly. 
      

      Is the video good when you configure the board for a resolution that does not use the SDRAM like HDMI 720p?  Is it possible the CVBS signal crosses the SDRAM lines in the layout?
      

      Please confirm.
      

      Thanks,
      Dharani S
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
						
						
				
				
		
		
      
			
		
      
	
      

      

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Reply

      


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													0
							
			
				
									
							        
			
			
			
      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Dec 12, 2023 8:41 AM
            
            
					
      
	
      

		
		
      
					
      Hi,
      

      We believe that the following things are already taken care of after changing the memory.
      

      You should be able to refer to ADV7842_External_Memory_Test_Rev0.pdf and ADV7842_Recommended_Settings_Rev2.0_241013.pdf.
      

      The DQML and DQMH pins of SDRAM were grounded properly. 
      

      Is the video good when you configure the board for a resolution that does not use the SDRAM like HDMI 720p?  Is it possible the CVBS signal crosses the SDRAM lines in the layout?
      

      Please confirm.
      

      Thanks,
      Dharani S
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
						
						
				
				
		
		
      
			
		
      
	
      

      

      • 


    


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