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QSerialPort Custom BaudRate

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  • N Offline
    N Offline
    Nex46
    wrote on last edited by
    #6

    It doesn't seem to work. I check the baud rate using myPort.baudRate() and the return value of setBaudeRate() and for 416000 it returns 9600 resp. false.
    It does accept 400000 and 500000, but not numbers in between.
    I've checked the setBaudRate function in qserialport.cpp, and it does not contain any check of valid values. It simply sets the BR. My only idea is that some other control function listens to the emitted signal and immediately sets it to default value again. ???
    I can communicate over serial interface in 416000 Bd using a python script so it's not a hardware issue.

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    • K Offline
      K Offline
      kuzulis
      Qt Champions 2020
      wrote on last edited by
      #7

      bq. I check the baud rate using myPort.baudRate() and the return value of setBaudeRate() and for 416000 it returns 9600 resp. false.

      What version of QSerialPort do you use?

      This behavior can be occured in QSerialPort < 5.3, when you try to setup baud rate if a device is not open. You can get error code to see what happens.

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      • N Offline
        N Offline
        Nex46
        wrote on last edited by
        #8

        I have Qt 5.3.1 installed and I set the baud rate after I've called open() function. I tried checking the error like this, just after I set the BR:
        @QSerialPort::SerialPortError e1 = myPort.error();@

        But I don't get any error message. It just returns 0.

        I do get the communication working through the port, but all data is just gibberish.

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        • N Offline
          N Offline
          Nex46
          wrote on last edited by
          #9

          Here's an printout of all baud rates accepted by setBaudRate() between 0 and 600000 in steps of 100.

          600000
          576000
          500000
          480000
          460800
          400000
          375000
          320000
          300000
          250000
          240000
          230400
          200000
          192000
          187500
          160000
          150000
          125000
          120000
          115200
          100000
          96000
          80000
          75000
          64000
          62500
          60000
          57600
          50000
          48000
          40000
          38400
          37500
          32000
          30000
          25000
          24000
          20000
          19200
          16000
          15000
          12800
          12500
          12000
          10000
          9600
          8000
          7500
          6400
          6000
          5000
          4800
          4000
          3200
          3000
          2500
          2400
          2000
          1800
          1600
          1500
          1200
          1000
          800
          600
          500
          400
          300
          200
          100

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          • K Offline
            K Offline
            kuzulis
            Qt Champions 2020
            wrote on last edited by
            #10

            Then you can try latest 5.3.3 sources of QtSerialPort (you should build it manually), there are added some patches to improve detection of custom divider and so on.

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            • N Offline
              N Offline
              Nex46
              wrote on last edited by
              #11

              I can confirm that the latest sources for QtSerialPort work with custom baud rate. Thanks for the help.

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              • K Offline
                K Offline
                kickoune103
                wrote on last edited by kickoune103
                #12

                i have Qt 5.5.1 (Clang 6.1 (Apple), 64 bit)
                Built on Nov 25 2015 01:02:16.

                i try to use QserialPort to 62500.
                i send QByteArray FF000000000000.
                at 115200 work fine with terminal in windows. (FF0000000.. in terminal).

                But if i add SetBaudRate(62500) before open ,(work return true).
                BUT don't work correctly in data.
                i connect terminal windows at 62500(works, i have capture correct trame in protocol who work in 62500)
                the data in terminal is different. C0 00 000...

                Can you help me? please.
                my project may be abandoned why don't work.

                i use two same USB-RS232 converter we work in 62500 ( in windows)
                USB CONVERTER(pc windows) ==> croissing wire ==> USB CONVERTER (in mac Qt)

                thank's

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                • mrjjM Offline
                  mrjjM Offline
                  mrjj
                  Lifetime Qt Champion
                  wrote on last edited by
                  #13

                  hi and welcome
                  Have you tried with other serial program on mac side to see
                  if qt or USB serial converter driver that is not working as expected with 62500
                  something like
                  http://www.macupdate.com/app/mac/31352/coolterm

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                  • K Offline
                    K Offline
                    kickoune103
                    wrote on last edited by
                    #14

                    cool term not work in 62500, i have test with: stty -f /dev/usb.serial... 62500
                    invalid argument... (work with 9600)

                    have you a term with we work with custom baud or a solution for testing the hardware?

                    thank's for your reply

                    mrjjM 1 Reply Last reply
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                    • K kickoune103

                      cool term not work in 62500, i have test with: stty -f /dev/usb.serial... 62500
                      invalid argument... (work with 9600)

                      have you a term with we work with custom baud or a solution for testing the hardware?

                      thank's for your reply

                      mrjjM Offline
                      mrjjM Offline
                      mrjj
                      Lifetime Qt Champion
                      wrote on last edited by
                      #15

                      @kickoune103
                      Ok. Im only on win and linux so mac is sort of unknown land to me.
                      https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man1/stty.1.html

                      here they mention
                      ispeed number/ ospeed number
                      Set terminal input baud rate to the number given, if possible. If the input baud rate i
                      set to zero, the input baud rate is set to the value of the output baud rate.
                      I wonder if it will allow to set it this way ?

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                      • K Offline
                        K Offline
                        kickoune103
                        wrote on last edited by
                        #16

                        i have solved this probleme to use qt6 beta.
                        with Qserialport 6.

                        but problem: setbaudRate(62500) return true before openning port but the open() bug...

                        the solution: open with standard baud and setBaudRate.

                        i think it's works, i have 0xFF00....

                        i have not tested in QT5.5 to setBaudRate(62500) after open().

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                        • K Offline
                          K Offline
                          kuzulis
                          Qt Champions 2020
                          wrote on last edited by
                          #17

                          with Qserialport 6.

                          there are no qt6 beta and Qserialport 6!

                          but problem: setbaudRate(62500) return true before openning port but the open() bug...

                          On my side (with the PL2303 and with built in on-motherboard's 16550 chip) all fine, so, please give more info or try to lookup a problem on your side.

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                          • K Offline
                            K Offline
                            kickoune103
                            wrote on last edited by
                            #18

                            sorry i use QT 5.6

                            http://download.qt.io/development_releases/qt/5.6/5.6.0-beta/

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