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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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How to restart the DRG sweep signal using only GPIO

		
	
				

			

									
					    TakeC
					
							

            
            			
				
									
											
			
			
				
			
			
			    	
			                    
                
				                on Dec 10, 2025 
				
			
			
		

		
		                    	    

        	    
Thread Summary

                The user wants to restart an ascending DRG sweep on the AD9910 DDS from the initial frequency after reaching the upper limit using only GPIO. The solution involves setting the No Dwell High feature and using the DRCTL pin to trigger the sweep restart. The DROVER pin can be used to detect when the sweep has completed and is ready to restart.
                        	    

                
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Category: Datasheet/Specs

    		        		            		    
Product Number:  AD9910  

    		        		    		    

		    		    
		    			

			    
When issuing a DRG sweep signal with the AD9910 DDS in the ascending direction only, with No-dwell-high on and No-dwell-low off,is there a way to restart from the initial frequency after reaching the upper frequency limit using only GPIO? Initially, I set CFR1 to CFR3, Digital Ramp Limit (0x0B), Digital Ramp Step Size (0x0C), and Digital Ramp Rate (0x0D), and then issue IO_UPDATE and DRCTL to control them.


After the DRO goes HIGH, I want to restart from the initial frequency using only GPIO control.

			

			
									
		                             
                        

    

                                            
                 Datasheet/Specs
                
                                                    
                 clock and timing
                
                                                    
                 Clocks & Timers
                
                                                    
                 Direct Digital Synthesis (DDS)
                
                                                    
                 ad9910
                
                                
            

    
    
		


				
				        
        		

			
						
									
												
			
			
                        
                                    
                        
                        
                        
            
			            
						
						
			
			
			
			
		


        
        
        
    
					

			





















	

	

					



			








	
	
	
	



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    •  Analog Employees  
    
            
						
                            
            
            				
            
                on Jan 5, 2026 9:33 PM
            
            
						
			            		
    
		
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    Hi  ,
    

    Just wanted to make sure this is what you're going for. You wanted to achieve the following:
    

      

    1. The sweep goes ascending.
      2. 

    2. When it reaches the top, it jumps back to the starting frequency because of No Dwell High. 
      3. 

    3. You want to restart the sweep again using only a GPIO pin (no reprogramming).
      4. 

    

    I believe DRCTL is one pin that can help you with your application. During no-swell operation, the DRCTL pin is monitored for state transitions only. 
    

    I suggest you do the following: 
    

      

    1. Set lower and upper limits.
      2. 

    2. Turn No Dwell High so it comes back to the lower limit after reaching the upper limit. 
      3. 

    3. To start the sweep, you can make the DRCTL pin from Low to High. This makes a rising edge. 
      4. 

    4. When it finishes and jumps back from the start, you have to make the DRCTL to high to start your new sweep. 
      5. 

    5.  If you want to check if the sweep is finished, you can use the DROVER pin. 
      6. 

    

    All the best,
    

    Jules
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
				
						
						
				
				
		
		
    
			
		
    
	
    

    

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                on Jan 14, 2026 6:06 PM
            
            
												
						in reply to Jules.Nikko
					
										
			            		
    
		
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    Hi Jules-san.
    

    Thank you reply and advice. we confirmed your advice. It works correctly.
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
						
				
						
				
				
		
		
    
			
		
    
	
    

    

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