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AD9957 Recommended for New Designs
The AD9957 functions as a universal I/Q modulator and agile upconverter for communications systems where cost, size, power consumption, and dynamic performance...
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How to write successfully user data to RAM in AD9957

		
	
				

			

									
					    bsalski
					
							

            
            			
				
									
											
			
			
				
			
			
			    	
			                    
                
				                on Dec 5, 2016 
				
			
			
		

		
		                     
				
        		

		    
		    		    
		    			

			    
Hi,

 
It seems that this issue has already been raised at this forum. Unfortunately, even though I tried to follow exactly the suggested steps I couldn't get the data successfully delivered to the memory in AD9957. In particular, I'm not sure how to organize the sequence of signals during RAM loading. I tried as follows:

 
1. CS = low

 
2. Send RAM address (0x16)

 
3. Send N 32-bit words one after another (with I/O_Update issued after each of them)

 
4. CS = high

 
Sometimes, I see that the first bit is changed but all the other are unaffected by the above procedure.

 
I will appreciate any suggestions.

 
Bartek

			

			
									
		                             
                        

    

                                            
                 Quadrature Digital Up Converters (QDUC)
                
                                                    
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                 ad9957
                
                                
            

    
    
		


				
				        
        		

			
						
									
												
			
			
                        
                                    
                        
                        
                        
            
			            
						
						
			
			
			
			
		


        
        
        
    
					

			





















	

	

					



			








	
	
	
	



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    •  Analog Employees  
    
            
						
                            
            
            				
            
                on Dec 5, 2016 10:04 PM
            
            
						
			            		
    
		
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    IO_Updates are not needed during writes to RAM.
    
 
    The RAM Segment Registers define the start and end address of RAM read/write operations. You program the RAM Segment Register(s) with the desired start/end addresses.
    
 
    You then select the desired RAM segment via the RT pin, where a 0-to-1 transition selects RAM Segment Register 1 and a 1-to-0 transition selects RAM Segment Register 0. The internal RAM controller "knows" how many 32-bit words to write (or read) per the start/end addresses in the selected RAM Segment Register.
    
 
    All you have to do is write (or read) the appropriate number of 32-bit words (based on the start/end addresses) to address 0x16.
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
						
				
						
				
				
		
		
    
			
		
    
	
    

    

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    •  Analog Employees  
    
            
						
                            
            
            				
            
                on Dec 5, 2016 10:04 PM
            
            
						
			            		
    
		
										0
					
	
    

		
		
    
		
    
                                
                                                            
    
					
    IO_Updates are not needed during writes to RAM.
    
 
    The RAM Segment Registers define the start and end address of RAM read/write operations. You program the RAM Segment Register(s) with the desired start/end addresses.
    
 
    You then select the desired RAM segment via the RT pin, where a 0-to-1 transition selects RAM Segment Register 1 and a 1-to-0 transition selects RAM Segment Register 0. The internal RAM controller "knows" how many 32-bit words to write (or read) per the start/end addresses in the selected RAM Segment Register.
    
 
    All you have to do is write (or read) the appropriate number of 32-bit words (based on the start/end addresses) to address 0x16.
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
						
				
						
				
				
		
		
    
			
		
    
	
    

    

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