1 Reply Latest reply on Nov 7, 2013 8:46 AM by gayathri.vasudevan

    is the fifo and the ep buffer the same

    wang.fei

      hi , when we talking about the fifo in the slave fifo or gpif fifo, is the fifo means the end point buffer ? that is ,if i use slave fifo , when the extern cpu writes one byte to the slave fifo , is it the cpu directly writes the byte into the end point buffer ,or the extern cpu just writes the byte into the fifo and then some logic in the ez-usb get the byte out of the fifo and then write it to the end point buffer ?

         

      thanks!

        • 1. Re: is the fifo and the ep buffer the same
          gayathri.vasudevan

           Hi,

             

           

             

          I believe you are referring in terms of FX2LP. FIFO and endpoint buffer is essentially the same physcal buffer. It is called as endpoint buffer when the FIFO is under the control of USB domain, else Slave FIFO. 

             

          It depends on which mode FX2LP is configured to work (auto/ manual), whether the data written to Slave fifo goes to EP buffer directly or not. In Auto mode, the data written to Slave FIFO is automatically committed to USB domain(the control is transferred to USB domain); i.e. is accessible as EP buffers. In manual mode, it has to be explicitly committed.

             

          I believe it would be clear with the AN http://www.cypress.com/?rID=12926.

             

           

             

          Regards,

             

          Gayathri