5 Replies Latest reply on Mar 31, 2015 8:36 PM by user_14586677

    usbfs design question

    user_352784942

      Hi,

         

      I am considering the design of an interface device (board) that essentially will make multiple USB devices appear as one USB device. 

         

      Just a bit of back ground.  I am an amateur radio operator and use a radio called the Peaberry V2.  I own multiple of these radios.  Currently each radio attaches to a PC via USB.  Each radio appears as a separate device on the PC.  Each radio has a operates on a unique band of frequencies.  Currently the PC host application needs to be stopped, reconfigured and restarted to switch between radios.  The idea is to use a PSoC 3 and configure multiple USBFS components (one for each radio) and then select a given USBFS component and route the data to a common USBFS component that is attached to the PC.  

         

      The interface device will do more than USB interfacing but I would like to know what folks think about this aspect first. 

         

      I need to stay with the PSoC 3 as this is the only chip that is available in a 48 pin configuration.  The board will be offered as kit and the 48 pin version is the only chip that can be reasonably be soldered into place by a kit builder

         

      Thanks for taking a look,

         

      Ron

        • 1. Re: usbfs design question
          user_14586677

          You might contact local sales office or manufacturers rep

             

          to confirm that specific part will be around for awhile, and

             

          how long.

             

           

             

          Just a thought.

             

           

             

          Regards, Dana.

          • 2. Re: usbfs design question
            user_352784942

            Hi Dana,

               

            I will do that.  That would be a bummer if the 48 pin version has a near term end of life.  The alternative is to have whatever company does the PCB fabrication install the PSoC.  But that would raise the cost of the kit and a lot of hams run a very thin budget

            • 3. Re: usbfs design question
              user_14586677

              The USBFS is a fixed function block, and only one allowed

                 

              to be instantiated. You might have to talk to a hub to accomplish

                 

              what you want.

                 

               

                 

              Or look at multilane Cypress parts, or the upcoming low cost PSOC 4 L

                 

              series (1 lane/).

                 

               

                 

                  

                 

                        http://www.cypress.com/?docID=49335

                 

               

                 

              Regards, Dana.

              • 4. Re: usbfs design question
                user_352784942

                Thanks again, Dana.

                   

                I would have been chasing my tail.   So, just for my education, what exactly is a fix function block?  And why only one instance?

                   

                Thanks,

                   

                Ron

                • 5. Re: usbfs design question
                  user_14586677

                  There are two main types of resources on PSOC,

                     

                  FF and UDB. The FF blocks are optimized HW,

                     

                  whereas the UDB much more programmable

                     

                  and general purpose. So a UDB can take on many

                     

                  personalities, but sacrifices optimal properties.

                     

                   

                     

                  The basic idea is to equip a part with commonly used, highly

                     

                  optimized capabilties, like COM and basic counter.... and use the

                     

                  UDB for design specific purposes and or more features than

                     

                  most commonly used types of HW.

                     

                   

                     

                  So a UDB counter, or PWM, has many more features than a

                     

                  FF one. Whenever possible one should use up the FF resources

                     

                  on chip if features adequate, then proceed to using UDB. Some

                     

                  functions only come in UDB however.

                     

                   

                     

                  The inevitable tradeoffs one makes in chip and product design.

                     

                   

                     

                  One instance, I would posit the USB transceiver, its power requirements,

                     

                  limited the number of USB channels.

                     

                   

                     

                  Regards, Dana.