seriall port from UC864-G

20 thoughts on “seriall port from UC864-G

  1. I work with a UC864-G FW 8.01.107. As I understand right there is one port for debug and one port for communication. I want to read GPS data with my processor and open at the same time a GPRS connection. Can I use for this Cmux? Or has this module  another possibility?

    1. I suppose you cannot use the USB drivers, in this case you can use CMUX or sockets with suspend periods or in command mode.

      1. thank you for the fast reply. What happen in the suspend mode if the server send data to the module, will they stored in the memory from module?

        1. Yes of course, here is a quote from AT Commands Reference Guide, AT#SD command:


          Note: if there are input data arrived through a connected socket and not

          yet read because the module entered command mode before reading

          them (after an escape sequence or after #SD has been issued with

          <connMode> set to command mode connection), these data are buffered

          and we receive the SRING URC (SRING presentation format depends on

          the last #SCFGEXT setting); it’s possible to read these data afterwards

          issuing #SRECV. Under the same hypotheses it’s possible to send data while in command mode issuing #SSEND.

          See also Easy GPRS User Guide.

  2. The UC864-G has two serial ports(one USB and one normal). Is there a possibility to use e.g. the USB for GPRS connection and the normal one for GPS data?

    I read the documentation, but I don’t find any hint in this matter. I hope you can clarify. Thank you.

    1. Here is from UC864 Software User Guide, and more about this is there:


      UC864-G Serial Ports
      4 serial ports are available on the module:


      You can do normal AT session on the serial port, including GPRS stuff, and read GPS NMEA strings from the third USB virtual port, as I said only if you can use the USB drivers.


  3. Thank you for your answer. Now comes up a new problem. I habe the module connected to the UART serial port, switch on power and get this output:


    ERROR:0x0004 Data Abort! TASK:FC Timestamp:01/01/2000 00:03:57
    REG[ 0] = 0x00000002
    REG[ 1] = 0x00000001
    REG[ 2] = 0x008bcb47
    REG[ 3] = 0x0200d050
    REG[ 4] = 0x0000001f
    REG[ 5] = 0x0257f5fc
    REG[ 6] = 0x00000e33
    REG[ 7] = 0x0000abab
    REG[ 8] = 0x0000abab
    REG[ 9] = 0x0000abab…..


    after this I can’t send any AT commands.

    After this I tried to update the firmware to the latest version with  Xfp2.06 and it don’t work too.

    What could be the reason for this behaviour?

    1. Did this happen suddenly or after a certain action?

      Is it a single module or there are more?

      Can you try firmware upgrade on it?


      1. – It happen after switch on immediately.

        – We have this behaviour with all modules.

        – As I mentioned before a upgrade don’t work to.

        1. I take a new one, switch it ON and it start with this behaviour. I send no command, I made no firmware update, nothing.

          1. Do you use a proper ON sequence, including 2 seconds of  low state of ON/OFF# pin and 10 seconds startup time after PWRMON goes high?


          2. I use a proper ON sequence in accordance to your documentation and after a few seconds the module starts sending the mentioned sequence on the serial port.


            After this stream is finished the module don’t response to any AT command.

          3. Let say in another words, for more clarity: the module remains switched ON or it shuts down after the stream above?

          4. I take a new one, switch it ON and it start with this behaviour. I send no command, I made no firmware update, nothing.

            1-So, how you have verified the firmware version of this module?


            2-could you post  the IMEI you should read on the module?


            3-could you remove the power supply, install the USB driver on PC and try to upgrade the firmware through  the USB diagnostic port?