1 Reply Latest reply on Mar 28, 2020 5:00 AM by EktaN_26

    USBUART Speed, only about 1.3Mbit?




      I've run the USBUART example with all the defaults for the CY8CKIT-030A kit and am having it send 256KB as fast as possible by looping transfer of 64 byte packets x 4096 times.


      The issue is that USBUART seems to be pretty slow, it's doing about 160KB/s which is about 1.3Mbit transfer. Is this normal? I was hoping to achieve maybe 3Mbit or more.




      Edit: I changed from Debug to Release compiling and that has sped it up a little bit more, 256KB/s. Is there anything else to make it faster?

        • 1. Re: USBUART Speed, only about 1.3Mbit?



          The USBUART component is implementation of a communications device class (CDC) USB interface. This is a USBFS Component with the descriptors configured to implement a CDC interface.


          The CY8BKIT-033A supports Full speed USB. Thus according to the USB specifications the maximum effective data rate is 1.2 MBps.

          The USBUART does not have any transfer rate limitation, but theoretically the transfer rate is limited by the USB Full Speed (12 Mbit/s- this is bus rate).

          The effective data rate transfer is 1.2 Mbps (The actual data rates are affected by bus loading, transfer type, overhead, OS, and so forth).


          For more details on this please refer to the page 11 of the USB 101 Appnote : https://www.cypress.com/file/134171/download

          You can also refer to the USBUART section of the USBFS datasheet: https://www.cypress.com/file/376416/download


          The above appnote also mentions the following:




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