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AD9910 Recommended for New Designs
The AD9910 is a direct digital synthesizer (DDS) featuring an integrated 14-bit DAC and supporting sample rates up to 1 GSPS. The AD9910 employs an advanced...
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AD9912 Recommended for New Designs
The AD9912 is a direct digital synthesizer (DDS) that features an integrated 14-bit digital-to-analog converter (DAC). The AD9912 features a 48-bit frequency...
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AD9910 RAM mode - writing whilst it is still enabled

		
	
				

			

									
					    Strontium-bham
					
							

            
            			
				
									
											
			
			
				
    
			
			
			    	
			                    
                
				                on Jul 2, 2021 
				
			
			
		
    
		
		                     
				
        		
    
		    
		    		    
		    			
    
			    
    Hi
    

    I have found that it is not possible to send sections of the RAM samples to two different DDS chips/channels at the same time. The only workaround I have found to this is to not disable the RAM when writing the RAM samples for the DDS second chip. For reference there are 1024 RAM words in total. For example for the first channel I have written to RAM words 0-24 and for the second channel I have used RAM words 25-49, but I have first disabled the RAM for channel 1, written the RAM values for the first channel, enabled the RAM and then written the  RAM words for the second channel without disabling the RAM again. To reiterate in the manual it states that it is strongly recommended not to do this, but is this to possible erroneous values or due to damage to the RAM of the board.
    

    Essentially I want to know whether I can write to the RAM whilst it is still enabled without damaging the board. I would really appreciate advice on this matter.
    

    
			
    
			
									    
    
			        
    Edit Notes
    
    				fixed typos
    
[edited by: Strontium-bham at 8:31 AM (GMT -4) on 2 Jul 2021]
				
    
						
		                             
                        

    
    
                                            
                 clock and timing
                
                                                    
                 ad9912
                
                                                    
                 dds
                
                                                    
                 Direct Digital Synthesis (DDS)
                
                                                    
                 ad9910
                
                                
            
    
    
    
		
    

				
				        
        		
    
			
						
									
												
			
			
                        
                                    
                        
                        
                        
            
			            
						
						
			
			
			
			
		
    

        
        
        
    
					
    
			
    


    
















    
	
    
	
    
					



			


				
	









	
      
	

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      •  Analog Employees  
      
            
						
                            
            
            				
            
                on Jul 12, 2021 9:15 AM
            
            
						
			            		
      
		
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      You did not mention if you are working with two AD9910 Evaluation Boards (EVBs) or a custom design PCB. In the case of EVBs, it is likely not possible to program RAM on two boards simultaneously. However, if you have a custom PCB, it should be possible to program RAM on two devices in parallel.
      

      It has been my experience that writing to RAM actually requires the RAM be enabled (contrary to the instructions). However, because RAM segments relate to Profiles, it would be difficult to properly coordinate Profile selection and RAM writes to two different devices.
      

      I would recommend having a single "RAM load" function that programs Profile 0 of both devices with a RAM segment spanning the length of the RAM (i.e., 0 to 1023). Then select Profile 0 and write all 1024 RAM samples to both devices (you should be able to write to RAM in both devices simultaneously). With the full set of RAM data loaded in both devices, go back to each device and program the RAM profiles with the desired address ranges for each RAM segment. You can then control the RAM data playback of both devices independently (via the Profile control pins of each device).
      

      Finally, to answer your last question, writing to RAM with RAM enabled will not damage the device.
      
			
      

		
			
	      

		
		
	
      
	
      
		
      
			
		
      
	
      
	
      
		
						
						
				
						
				
				
		
		
      
			
		
      
	
      

      

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