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ADV7182A Recommended for New Designs
The ADV7182A has the same pinout and is software compatible with the ADV7182. The ADV7182A is a versatile, one chip, multiformat video decoder that automatically...
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ADV7182A on Analog.com

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ADV7182A Use of VDP for slicing WST

		
	
				

			

									
					    AvroVulcanXH607
					
							

            
            			
				
									
											
			
			
				
			
			
			    	
			                    
                
				                on May 6, 2026 
				
			
			
		

		
		                     
				
        		

		    
		    		    

		      		            		        
Category: Hardware

    		        		            		    
Product Number:  ADV7182A  

    		        		    		    

		    		    
		    			

			    
I am trying to use the built-in VDP to decode World System Teletext, but I am getting very unexpected results. The data structure looks correct, however the actual data is extremely garbled - for example, the framing code should be 0x27, according to the datasheet - however, I am seeing 0xEA. This does not seem to change when forcing a standard vs. autodetect. Is there any more in-depth info on how to correctly set up and test the VDP function.

			

			
									    

			        
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[edited by: AvroVulcanXH607 at 6:14 PM (GMT -4) on 6 May 2026]
				

						
		                             
                        

    

                                            
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    •  Analog Employees  
    •  Super User  
    
            
						
                            
            
            				
            
                on Jun 29, 2026 5:26 AM
            
            
						
			            		
    
		
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    Hi,
    

    Please ensure when teletext is detected by the ADV7182A, the TTXT_AVL bit will go high (Interrupt map, register 0x78 bit [7]). However this bit will remain high until cleared. This ensure that the teletext signal which only appears briefly on some lines of video is detected.
    

    The TTXT_AVL bit will remain high until it is cleared. To clear the TTXT_AVL bit write 0x80 to Interrupt map, register 0x78. The clear bit ofr the TTXT_AVL bit is missing from the ADV728x hardware manual. 
    

    

    Please refer below thread. In this thread, the expert provided a suggestion regarding register setting and clearing of ‘TTXT_AVL’ (Interrupt map, register 0x78, bit [7]).
    

     ADV7280 teletext detected not working 
    

    

    Thanks,
    

    Poornima S
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
						
				
						
				
				
		
		
    
			
		
    
	
    

    

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    •  Analog Employees  
    •  Super User  
    
            
						
                            
            
            				
            
                on Jun 29, 2026 5:26 AM
            
            
						
			            		
    
		
										0
					
	
    

		
		
    
		
    
                                
                                                            
    
					
    Hi,
    

    Please ensure when teletext is detected by the ADV7182A, the TTXT_AVL bit will go high (Interrupt map, register 0x78 bit [7]). However this bit will remain high until cleared. This ensure that the teletext signal which only appears briefly on some lines of video is detected.
    

    The TTXT_AVL bit will remain high until it is cleared. To clear the TTXT_AVL bit write 0x80 to Interrupt map, register 0x78. The clear bit ofr the TTXT_AVL bit is missing from the ADV728x hardware manual. 
    

    

    Please refer below thread. In this thread, the expert provided a suggestion regarding register setting and clearing of ‘TTXT_AVL’ (Interrupt map, register 0x78, bit [7]).
    

     ADV7280 teletext detected not working 
    

    

    Thanks,
    

    Poornima S
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
						
				
						
				
				
		
		
    
			
		
    
	
    

    

    • 





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