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CAlex's avatar
CAlex
Icon for Contributor rankContributor
3 years ago

Baremetal with UART(RS232) issue

Hi,

according to the user manu of Cyclone V soc said, the UART is up to 1Mbps for RS232 communication,

But when checking the examples of 16550 UART, the rate is set to 115200 bps for maximum.

I checked the clock of the UART (L4 SP TIMER) is 100MHZ. So it can be faster than 115200bps,right?

Yet when I checked the 16550 UART Hwlib code the maximum enum was 115200.

So I have the following questions:

How can I make it faster(reaches 1Mbps in 8N1 mode)?

reguards.

4 Replies

  • aikeu's avatar
    aikeu
    Icon for Regular Contributor rankRegular Contributor
    3 years ago

    Hi CAlex,


    Are you referring to the soft UART 16550 uart IP from the embedded peripheral user guide?

    https://www.intel.com/content/www/us/en/docs/programmable/683130/21-2/introduction.html


    For Cyclone V HPS there are two in build hard UART, UART0 and UART1.

    Seems like most standard communictiona speed which I commonly see for UART is 115200bps. I think to have a higher bps it might probably has a higher chance to introduce error in the data sending.


    Thanks.

    Regards,

    Aik Eu


    • FvM's avatar
      FvM
      Icon for Super Contributor rankSuper Contributor
      3 years ago
      HPS UART supports up to 6.25 Mbps with 100 MHz clock according to processor manual, just need to program baud generator registers respectively. Hardware wise, the high baud rates are well possible with RS-485 interface. RS-232 works with 923 kbps as highest standard rate on most PCs.
  • aikeu's avatar
    aikeu
    Icon for Regular Contributor rankRegular Contributor
    3 years ago

    Hi FvM,


    Thanks for the additional info.


    Hi CAlex,


    I will close this thread if there is no further question.


    Thanks.

    Regards,

    Aik Eu


  • aikeu's avatar
    aikeu
    Icon for Regular Contributor rankRegular Contributor
    3 years ago

    Hi CAlex,


    I am closing this thread for now. If any answer from the community or Intel Support are helpful, please feel free to give best answer or rate 4/5 survey.


    Thanks.

    Regards,

    Aik Eu