Issue with Linmux multiplex serial driver for EH6ST | Telit Cinterion IoT Developer Community
March 9, 2018 - 11:21am, 4757 views
Hi I compiled and installed the linmux driver as kernel module on an ARM based embedded Linux board.
I connect this board t0 an EH6ST terminal via the RS232 port. I can do a ppp connection and also see the virtual ttyMux devices under /dev but cannot use any of the 3 for AT commands. Using minicom with the virtual ports give me a no such file or device error.
I expected to see the virtual tty ports with dmesg, but only the base port ttyS0 shows. Is there anything in the actual driver source I need to change to get this to work or any other debugging suggestions.
Thank you
Travers
Hello,
Have you tried with some Linux PC distribution for reference?
Maybe there is some problem specific to your ARM based Linux board.
Regards,
Bartłomiej
Thanks,
I am trying on Ubuntu
Distributor ID: Ubuntu
Description: Ubuntu 16.04.3 LTS
Release: 16.04
Codename: xenial
Kernel version 4.13.0-36-generic
I get the same results. the mux ports are visible under /dev but not accessible
minicom: cannot open /dev/ttyMux0: No such device.
In this case I cannot use the linmuxcfg tool. It simply exits with "killed"
Hi,
Have you checked the status of the access rights (write/read/execute) for the ports?
If it is like "-rw-r--r--. 1 root root 46701 Jul 31 09:58 index.html", you can write "chmod 666 * " and
get "-rw-rw-rw-. 1 root root 46701 Jul 31 09:58 index.html"
Best regards,
Antero
Antero Markkula
Communication and Mechatronics
Enkom Active Oy – www.enkom-active.fi
Upseerinkatu 3 A, 02600 Espoo, Finland
Mobile: +358 400 411368
Office: +358 10 204 0000
Fax: +358 10 204 0010
E-mail: antero.markkula@enkom-active.fi
Thanks Antero, it was like below, I changed the access rights and ownership to what you suggested, but still the same results.
crw-rw---- 1 root dialout 195, 0 Mar 12 14:25 ttyMux0
crw-rw---- 1 root dialout 195, 1 Mar 12 14:25 ttyMux1
crw-rw---- 1 root dialout 195, 2 Mar 12 14:25 ttyMux2
Thanks
Travers
Hi,
Do you have all RS232 lines connected? This is important for the MUX to work.
Regards,
Bartłomiej
Hi on the pc linux ubuntu I use a usb to serial converter cable, picked up by the system as a proific pl2303 chipset. As far as I know all rs232 signals are available.
On the embedded board I have not connected DSR, DTR and RING. I wil try the embedded side with those connected, but am still not sure why it is not working on the pc.
Hi!
The MUX protocol requires minimum CTS, RTS and DTR.
RING, DSR and DCD are also recommended for correct virtual port handling.
Regards,
Antero
Antero Markkula
Communication and Mechatronics
Enkom Active Oy – www.enkom-active.fi
Upseerinkatu 3 A, 02600 Espoo, Finland
Mobile: +358 400 411368
Office: +358 10 204 0000
Fax: +358 10 204 0010
E-mail: antero.markkula@enkom-active.fi
Hi thanks,
Do I understand correctly that the virtual ports will then only be accesible when the base port is opened and connected to the modem ? When the kernel module is loaded, I do see them under /dev so they are created
For my embedded board I do not have a DTR signal. Will it work if I wire it as a loopback null modem - that is DTR,DSR and DCD connected to each other ?
Hello,
I think that the converter might be a problem. Linmux checks the DSR Line if the module is on. For testing you may modify baseport.c => static BOOL bp_IsModulePowerOn() to skip the DSR check.
You can also do some settings for debug in the code.
Debug Zone: in muxdbg.h set the DEFAULT_TRACE_MASK to
(ZONE_RESERVED | ZONE_ERR | ZONE_DRV_INIT | ZONE_GENERAL_INFO | ZONE_MODULE_EXIT | ZONE_AT_CMDS | ZONE_FCT_TTY_IFACE)
Baseport: Check the values of
pBasePort->m_strPortName
DEFAULT_BASEPORT_NAME
Regards,
Bartłomiej
Thanks Bartłomiej, I think I am making some progress now. I now get a different error when trying to connect to the mux ports. At least not No such device anymore.
minicom: cannot open /dev/ttyMux0: Connection timed out
The above takes quite a long time.
Also what i find is if I open minicom on the base port I can issue at commands and as soon as I try and open another minicom with a mux port ttyMux0, I get an ERROR on the base port terminal and looks like a restart of the modem (SMSO) and can indeed see the modem restart.
To get to this point I disabled DSR checking and confirmed my baseport name is correct
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