Products In This Thread

ADV7181C Production
The ADV7181C is a high quality, single-chip, multiformat video decoder and graphics digitizer. This multiformat decoder supports the conversion of PAL...
Datasheet
ADV7181C on Analog.com

  • State Verified Answer
  • Replies 6 replies
  • Subscribers 80 subscribers
  • Views 1833 views
  • Users 0 members are here
Options
Related 

        

            Post
             Go back to editing
        

    

    


    

    









		












	
	
			
	
			
		
	
	
		

		
ADV7181C I2C access



		

			

									
					    Eduardo
					
							

			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Nov 20, 2012 
				
			
			
		
    

				
		
    
		    		    
		    
		    	
			
    We are at the early stages of debugging a video board using the ADV7181C video serialiser.
    
 
    When I write (R/W = W) a command through the I2C interface to the chip using address 0x21 (or 0x42 as stated in the manual) I receive an ack per each byte sent. This is good 
    
 
    But  when I try to receive data (R/W = R) from this same address the address byte is not acknowledged and of course no communication takes place.
    
 
    The manual creates some confusion in my mind about the I2C address, should it be shifted, should it not! Although I've tried all possible addresses and the only that is acknowledged when writing is in fact 0x21.
    
 
    Could anyone give me some ideas about this? 
    
 
    thanks
    
 
      Eduardo
    
									
			        
		
    

				
				
		
    
			
						
									
									
						
						
			
			
			
			
		
    

        
        

					
    
			
    


    


	
    
		
	
    















    
	
    
	
    
					



			








	
	
	
	



Parents
	
      
	

    • 
	
      



	
		
	
	



      
	
      
		
      
							
					
      
		
      
			
													0
							
			
				
									
							        
			
			
			
        
            
			                            
                        
                on Nov 20, 2012 12:07 PM
            
            
					
        
	
        

		
		
        
					
        I was able to find some clue about the abnormal behaviour related before.
        
 
        According to the ADV7181C_Manual_RevC.pdf a read sequence should be as follows (see also the picture attached):
        
 
        START  SlaveAddr  Ack(Slave)  SubAddr  Ack(Slave)  START  SlaveAddr  Ack(Slave)  Data  Ack(Master)  ...  Data  /Ack(Master)  STOP
        
 
        Apparently the ADV7181C expects two START bits in order for a read sequence to be done.
        
 
        Can some one acknowledge that this is the proper way to do a read?
        
 
        thanks
        
			
        

		
			
	      

				
        
			
			
		
        
			
		
	
        
	
        
		
        
			
		
        
	
        
	
        
		
						
						
				
						
				
				
		
		
        
			
		
        
	
        

        

        • 

	
      



Reply

        


      • 
	
        



	
		
	
	



        
	
        
		
        
							
					
        
		
        
			
													0
							
			
				
									
							        
			
			
			
          
            
			                            
                        
                on Nov 20, 2012 12:07 PM
            
            
					
          
	
          

		
		
          
					
          I was able to find some clue about the abnormal behaviour related before.
          
 
          According to the ADV7181C_Manual_RevC.pdf a read sequence should be as follows (see also the picture attached):
          
 
          START  SlaveAddr  Ack(Slave)  SubAddr  Ack(Slave)  START  SlaveAddr  Ack(Slave)  Data  Ack(Master)  ...  Data  /Ack(Master)  STOP
          
 
          Apparently the ADV7181C expects two START bits in order for a read sequence to be done.
          
 
          Can some one acknowledge that this is the proper way to do a read?
          
 
          thanks
          
			
          

		
			
	      

				
          
			
			
		
          
			
		
	
          
	
          
		
          
			
		
          
	
          
	
          
		
						
						
				
						
				
				
		
		
          
			
		
          
	
          

          

          • 


        


Children
	
        No Data