6 Replies Latest reply on Nov 18, 2011 2:17 AM by amit.karna

    Queries for design of Hub controller

    amit.karna

      Hi,

         

      I'm designing a 4 port USB 2.0 multi TT Hub controller and for which I have selected the "CY7C65642" device.

         

      I have referred the datasheet and have following queries:

         

      [1] CY7C65642 have the option of using the default descriptors to configure the hub with default VID and PID are 0x04B4 and 0x6572. On power up, CY7C65642 has an option to enumerate from the default settings in the mask ROM or from reading an external EEPROM for configuration information.

         

      In my design VID and PID values are not important. Can I go ahead for the design without using EEPROM ?

         

      [2] I do not have requirement of LED indicators and hence have chosen 28 QFN. Now my query is QFN does not support pin strapping and other pin configuration options. Are the default setting enough to make it work as a multi TT 4 downstream USB port ?

         

       

         

      [3] Assuming I design without EEPROM, what all programming consideration are to be taken, if any ? Also, any hardware setting to be done while designing ?

         

      Reply ASAP... thanks.

        • 1. Re: Queries for design of Hub controller
          anand.srinivasan.asokan

           1. Please look at http://www.cypress.com/?app=forum&id=167&rID=54575

             

          2. The default values configure the hub as a multi-TT 4 port hub.

             

          3. If there is no EEPROM there is no programming invovled. Please provide more information on the kind of consideration you're talking about.

             

          Regards,

             

          Anand

          • 2. Re: Queries for design of Hub controller
            amit.karna

             Hi Anand,

               

            Thank you for a quick reply.

               

             

               
            I am designing ARM processor based embedded board on which Ubuntu Linux will be ported. The microprocessor selected has two USB ports, which we plan to extend in the following 2 configurations:  We have selected the device "CY7C65642-28AXC".   Configuration A: 1 USB hub per port for two USB ports--> 8 USB endpoints  Configuration B:  1 USB hub for 1 port -->  3 ports + second hub to be extended from the 4th port => to get 7 USB endpoints  As per my understanding, the EEPROM is being used for PID and VID settings which can be default. As per the datasheet, on power up, CY7C65642 has an option to enumerate from the default settings in the mask ROM or from reading an external EEPROM for configuration  information.   My further queries are:  3. If I don't use EEPROM, will there be any issue at the software/driver level in both config. A & B ?  4. The USB hub design will be self-powered. In config B, will there be any speed/current constraint and the end  point ?  5. Availability of 28 QFN device and support time line. Also, do you provide industrial version (operating temperature) of the device ?  Regards, amit
            • 3. Re: Queries for design of Hub controller
              prajith.cheerakkoda

               Hi,

                 

                       3.For your first question please look at http://www.cypress.com/?app=forum&id=167&rID=54575

                 

                      4. No, there is no constraints on current and speed. 

                 

                      5. Before answering this question please let me know the device that you have seleted. The one that you have mentioned ( CY7C65642-28AXC )in the post is not a valid device.

                 

              Thanks,

                 

              Prajith

              • 4. Re: Queries for design of Hub controller
                amit.karna

                Hi Prajith / aasi,

                   

                Thank you for clarifying my doubts. I referred to the link as suggested.

                   

                 

                   

                3. It's a embedded design using Linux OS, so should not be a problem.

                   


                5. Before answering this question please let me know the device that you have seleted. The one that you have mentioned ( CY7C65642-28AXC )in the post is not a valid device.

                   

                >> refer http://www.cypress.com/?mpn=CY7C65642-48AXC. The datasheet has information about both 28 QFN and 48 TQFP. I also came to know that 28 QFN is available for prototype sampling, expected to be released by 1 week of December. And also the that the Industrial grade is expected to be released in Jan 2012.

                   

                 

                   

                Let me know if you have any suggestion in particular. I am planning to go ahead with self powered CY7C65642-28AXC in the config. B (see previous post) without EEPROM.

                   

                 

                   

                Regards,

                   

                Amit

                • 5. Re: Queries for design of Hub controller
                  anand.srinivasan.asokan

                  Due to 2 hub chips in the path there will be slightly higher delay for 2nd hub ports but it is of the order of ns so I don't see any reason for concern.

                     

                  In either case you'll have 8 ports (you forgot to count one of the hosts USB ports in config B)

                     

                  Regards,

                     

                  Anand

                  • 6. Re: Queries for design of Hub controller
                    amit.karna

                     Hi Anand,

                       

                    Thank you. You have correctly pointed out that there will be 8 end points. But in my design, the processor USB hosts can be configured as device/host. So, I am planning to extend 1 USB port with hub to 7 end points and the second USB port will be configured as USB device.

                       

                    Thank you again Anand and Prajith for quick replies. This forum by Cypress is very helpful.

                       

                    Regards,

                       

                    Amit