2 Replies Latest reply on Apr 28, 2015 3:54 AM by userc_41454

    FX3 GPIF Transitions definition





      I'm curently developping an application on the FX3 and I want to make a dynamic GPIF system. I mean, I wan't to program new waveforms without having to compile the application or have a fixed set of configurations, as we could do in the FX2LP.


      Currently, I've looked at the GPIF registers, and I came accross a problem to populate the GPIF_FUNCTION registers. i've tried to find how are these transistions defined (the GPIF designer generate these values but I can't find how does it work. The FX3 TRM is quite light on this point as it states 'Truth table for transition function. Bit position X contains output when the 4 inputs constitute the value X in binary. For example, bit 2 = 1 means in3 = 0, in2 = 0, in1 = 1 and in0 = 0 will evaluate true for this function.' but it doesn't state were does inX comes from). I've tried to find a relation between a simple GPIF design and the transistion parameters but couldn't find it.


      Can you please explain me how does it work.




      Regards, Jerome

        • 1. Re: FX3 GPIF Transitions definition

           Hi Jerome,


          The low level details of the Waveform and transition registers are usually not availale for customers. It is not recommended to play around with those registers directly, without using the Gpif State Machine tool.


          We recommend you to have fixed set of state machines and switch from one to another whenever required.


          Can you please let me know why you do not prefer having fixed set of state machine configurations? I will see if I could suggest you any other solution as per your application.




          - Madhu Sudhan

          • 2. Re: FX3 GPIF Transitions definition





            Thanks for the answer.


            I need to be able to program the GPIF waveform dynamically because I can sample the GPIF port at different speeds depending on the host application settings.


            I was doing this easily with the FX2LP so I really wan't to do it with the FX3 to have the benfit of the 32bit and USB3.


            Regards, Jerome