5 Replies Latest reply on Mar 1, 2013 1:00 PM by gayathri.vasudevan

    FX2LP Isochronous

    jon.bean

       I am using a FX2LP that sets endpoint 6 to IN. The data is coming from an FPGA connected to the FIFOs of the FX2LP. Is there a way to determine when the host sends an IN packet to request data. I want to know this as I am using a feedback endpoint and want to return the count when the host requests it.

         

      Thanks

         

      Jon

        • 1. Re: FX2LP Isochronous
          gayathri.vasudevan

           Hi,

             

           

             

          Did you mean that you want to get notification whenever host takes a packet from the IN endpoint? if so, you can make use of Endpoint interrupts. Please refer section "endpoint interrupts" in EZUSB TRM (http://www.cypress.com/?rID=38232) for details.

             

           

             

          Regards,

             

          Gayathri

          • 2. Re: FX2LP Isochronous
            jon.bean

             No I want to get notified when the host sends an IN request to the Fx2LP. I want to know that it has requested some data.

               

            Thanks

               

            Jon

            • 3. Re: FX2LP Isochronous
              gayathri.vasudevan

               Hi,

                 

               

                 

              Can you please share why you want to get notified for every IN token from the host? How are you using that in your application. There is no direct notifcation available for that in FX2LP. If we understand what you are trying to do, we may be able to suggest some alternatives for the same.

                 

               

                 

              Regards,

                 

              Gayathri

              • 4. Re: FX2LP Isochronous
                jon.bean

                 I am using the FX2LP as an audio speaker. I want to implement an async arrangement were I have a data endpoint (0x02) and a feedback endpoint (0x86). The feedback data count is located in an FPGA. So I need to send the feedback count every time the host send the IN request. I guess I will just have to send the data to the FX2LP at the feedback sample rate if there is no way to know when an IN packet has been received. Its not a big problem to do it this way I just thought there would be a way to know when an IN packet was recieved.

                   

                Thanks

                   

                Jon

                • 5. Re: FX2LP Isochronous
                  gayathri.vasudevan

                   Hi,

                     

                   

                     

                  You can keep committing the required feedback data in the IN endpoint to the host domain. Once committed, the data will e sent to the host whenever IN token is received from the host. Also, in case of Isochronous transfers, depending on number of packets per microframe setting, so many number of IN token will be issued by the host in a microframe. 

                     

                  So, i believe you can just keep committing the data in case of manual mode. In case of auto mode, as soon as the data comes from FPGA, it gets committed to teh host domain. Once the data is in host domain, it is sent to host whenever an IN token comes. there is no need for firmware do anything explicitly to send the data when an IN token comes. I believe this answers your query. If I misunderstood, please clarify me.

                     

                   

                     

                  Regards,

                     

                  Gayathri