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TMS320F28075: Baud rate for USB virtual serial port

Linda Zhang84708
Expert 5775 points
Part Number: TMS320F28075
Other Parts Discussed in Thread: CONTROLSUITE

Hello Champs,

After running F2807x "usb_dev_serial" example codes and installing driver in controlSUITE, as below picture, the maximum baud rate of virtual serial port is 128000, would you please kindly suggest how to increase it to 921600 or above (eg. 1843200)? Thanks!

Best Regards,

Linda

  • 0
    TI__Mastermind 32995 points
    Hi Linda,

    The example works at 115200 baud rate. The limitation you are seeing is from whatever application you are using.

    Additionally, the baud rate will only physically effect the SCI/UART communication. The full speed USB communication baud rate/ bit rate is not effect. It has its own protocol and own bit rate.

    Hope this helps,
    sal
  • 0 in reply to Sal Pezzino
    TI__Expert 5775 points
    Hello Sal,

    Thank you for your reply. That means if use UART application which can set baud rate to 1M or above, F28075 USB virtual serial port can support this without modifying driver, is it right?

    Another question is: Shall we have F28075 USB host communication example codes(only transmit/receive data)? Thanks!

    Best Regards,
    Linda
  • 0
    Genius 5885 points

    XDS100 is based upon FTDI which can go up to 1.5 Mbps, you should check FTDI datasheet for precise baudrates avialable.

    With TMS28377 clocked at 200 MHz, you can easily do 1.0 Mbps. If you clock it down to 120 MHz you can even do 1.5 Mbps, but if you can afford downclocking.

    You do need a terminal which can open COM port at custom baudrate. The list of available baudrates shown on your screenshots is not written in stone. You can open a COM port on FTDI at any baudrate, but the FDTI will open it at the closes frequency it can.

  • 0 in reply to Mitja Nemec
    TI__Mastermind 32995 points
    Hi Linda,

    We do not have a USB Bulk Host example. But you can see the other host examples for reference.

    I believe when opening the COM port to the USB communication, the baud rates may still need to match. Although, I am not positive. You should not have to change the driver. The baud rate information should not be contained in the actual Windows driver.

    Also, please consider Mitja's comments. Thanks, Mitja!

    Regards,
    sal
  • 0 in reply to Sal Pezzino
    TI__Expert 5775 points
    Hello Sal,

    Thank you for your kind help. I have already successfully set the baud rate to 921600.

    There is another question: USB_dev_serial demo codes need to open two terminal windows with this virtual serial port and another serial port and then send data each other.

    Currently customer needed to only use this virtual serial port (one terminal window) to send data and receive data through USB and then also display in the same terminal window. Would you please kindly suggest how to modify the codes step by step? Thanks!

    Best Regards,
    Linda
  • 0 in reply to Linda Zhang84708
    TI__Mastermind 32995 points
    Hi Linda,

    This should not be that difficult to modify. All of the SW pieces are present in the example itself to accomplish this.

    You can either use the SCI or the USB to do both the reading and the writing to a single COM port on the PC.

    If you have more specific questions, we would be glad to assist you.

    Regards,
    sal
  • 0 in reply to Sal Pezzino
    TI__Expert 5775 points
    Hello Sal,

    Currently if sending data in the virtual serial COM port terminal, the received data will display in the other COM port terminal and the code will go into "USBUARTTXIntHandler". if sending data in the other COM port terminal, the received data will display in the virtual COM port terminal and the code will go into "USBUARTRXIntHandler".

    If I need to send data in virtual COM port terminal and then the received data will still display in virtual COM port terminal, how should I modify the codes? Would you please kindly suggest? Thanks!


    Best Regards,
    Linda
  • 0 in reply to Linda Zhang84708
    TI__Mastermind 32995 points
    Linda,

    There is both SCI communication and USB communication in this example. It appears you want to send and receive both with USB only. I cannot modify the example for your specific request, but it should not be that involved. Alternatively, you can also look at the usb_bulk_example project which uses only USB for both sending and receiving characters.

    Regards,
    sal