5 Replies Latest reply on Nov 11, 2012 6:40 AM by userc_43821

    RFID reader interfacing to PSOC3

       i'm in a dilemma whether to use the internal default ISR or a user defined one when my RX buffer size is greater tha 4 bytes and when i tried using the UART example project for PSOC3 it worked fine with the hyperterminal doesn't the same code apply to a RFID  reader interfacing ?? when i tried using the same code my LCD wasn't displaying anything...what might be the problem ?? and when we set our buffer size 12 bytes ...when is the recieve interrupt actually generated after it recieves the first byte or after 12 bytes?? in need of urgent help 

        • 1. Re: RFID reader interfacing to PSOC3

          As you can see when changing the buffer size for the Rx-Buffer the interrupt for receiving a character is grayed out. That is because the software takes over to handle incoming characters and put them into the buffer. So just the remaining Rx-interrupt causes as overrun, parity and similar errors will be used. There is a chance to include some code in the UART's interrupt handler at the point a character is received.


          I would suggest you to start writing your own code and handler. Begin with a non-interrupt solution which polls for the buffer containing the number of characters you expect(12) but choose a buffer-size that is larger. That can give you some headroom when processing on message and there is no time to poll.




          Happy coding



          • 2. Re: RFID reader interfacing to PSOC3

            Leaving the Rx buffer at 4 bytes, using the Rx buffer ISR, certainly


            implementing a fifo copy into a buffer with a address pointer straight


            forward. This approach requires you look at code execution time,


            especially at higher baud rates.




            Alternatively use component editor and create your own, or use verilog to


            create your own handler.




            It would be advisable, for error reasons, if there was a framing byte or indication


            of some sort for the 12 bytes.




            Regards, Dana.

            • 3. Re: RFID reader interfacing to PSOC3

              I forgot this is RFID, generally speaking data rates not all that high,


              so code execution time may be irrelevant.




              Regards, Dana.

              • 4. Re: RFID reader interfacing to PSOC3

                 Thanx guys for your valuable advises i'll try out the suggestions made by you and get back to ypu

                • 5. Re: RFID reader interfacing to PSOC3

                  You are always welcome!