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Sending TWI commands/data without the preceding device address?

		
	
				

			

									
					    jeffmo77
					
							

            
            			
				
									
											
			
			
				
			
			
			    	
			                    
                
				                on Mar 22, 2019 
				
			
			
		

		
		                     
				
        		

		    
		    		    
		    			

			    
Hello, I am trying to communicate with a Newhaven LCD display using the ADSP-21469 EZ-KIT and the TWI interface in Master mode.  I have set everything up and am able to send commands and data to the display and I am able to see the acknowledgement bit assert using an oscilloscope.  However, the device is not displaying anything after duplicating the manufacturer's initialization procedure.  One thing I've noticed is that the TWI controller always sends the slave address prior to each byte of data, and I am wondering if this is the problem.  Is it possible to simply send a byte of data without the preceding slave address when using the TWI interface?  Thank you in advance for your help!

			

			
									
		                             
                        

    

                                            
                 Audio Signal Processors
                
                                                    
                 adsp-21469
                
                                                    
                 SHARC Audio Processors/SoCs
                
                                
            

    
    
		


				
				        
        		

			
						
									
												
			
			
                        
                                    
                        
                        
                        
            
			            
						
						
			
			
			
			
		


        
        
        
    
					

			





















	

	

					



			








	
	
	
	



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    •  Analog Employees  
    
            
						
                            
            
            				
            
                on Apr 4, 2019 2:53 AM
            
            
						
			            		
    
		
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    Hi Jeff,

    As mentioned in the HRM under "Master Mode Addressing" section, whether enabled as a master-transmitter or master-receiver with 7-bit addressing using the TWIMLENbit, the TWI master performs all addressing and data transfers as required. This includes generating the repeated start condition, re-transmission of the 7-bits of the first address byte, and acknowledgement and generation of a new transfer direction change (indicated by the TWIMLENbit).

    Please find the attached TWI Code for your reference. We have configured ADSP-21479 as a master and another ADSP-21479 as a slave. Please use this as reference and modify as per your requirement.
    

    TWI_Master_21479.zip
    

    

    TWI_Slave_21479.zip
     
    Regards,
    Lalitha.S
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
				
						
						
				
				
		
		
    
			
		
    
	
    

    

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    •  Analog Employees  
    
            
						
                            
            
            				
            
                on Apr 4, 2019 2:53 AM
            
            
						
			            		
    
		
										+1
					
	
    

		
		
    
		
    
                                
                                                            
    
					
    Hi Jeff,

    As mentioned in the HRM under "Master Mode Addressing" section, whether enabled as a master-transmitter or master-receiver with 7-bit addressing using the TWIMLENbit, the TWI master performs all addressing and data transfers as required. This includes generating the repeated start condition, re-transmission of the 7-bits of the first address byte, and acknowledgement and generation of a new transfer direction change (indicated by the TWIMLENbit).

    Please find the attached TWI Code for your reference. We have configured ADSP-21479 as a master and another ADSP-21479 as a slave. Please use this as reference and modify as per your requirement.
    

    TWI_Master_21479.zip
    

    

    TWI_Slave_21479.zip
     
    Regards,
    Lalitha.S
    
			
    

		
			
	      

		
		
	
    
	
    
		
    
			
		
    
	
    
	
    
		
						
				
						
						
				
				
		
		
    
			
		
    
	
    

    

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