Serial only receive 1 byte

[andarm]

run on window

• used modusslave-tool test .

  sendbuf := []byte{0x40, 0x02, 0x00, 0x00, 0x00, 0x6E, 0xF6, 0xF7}
      n, err := s.Write(sendbuf)
  if err != nil {
      s.Close()
      fmt.Println("write close")
      log.Fatal(err)
  }
  
  buf := make([]byte, 128)
  
  n, err = s.Read(buf)
  if err != nil {
      fmt.Println("read close")
      log.Fatal(err)
  }

  • receive len ｎ＝１　byte . // Normal receive is : 40 02 0E 00 00 00 00 00 00 00 00 00 00 00 00 00 00 4E C1 ,but I only got one byte.
  • serial config

    c := &serial.Config{Name: "COM5", Baud: 9600, ReadTimeout: time.Second * 5}

[xiegeo]

You need to put read in a loop. Use the third byte to calculate total length.

If you need something that also takes timing into consideration and handles more opcodes, you can check out my code here https://github.com/xiegeo/modbusone/blob/master/packet_reader.go

[andarm]

Thanks ,I got it.