Use FTDI cable on Omega's USB port



  • I have a Omega 2+ with the Power dock and an OLED expansion.

    I'm trying to make a module to connect to the smart meter in my house in order to send HTTP queries to an influxDB in another device in my network.

    The smart meter can be communicated using RS232 interface, although only RxD is available and it needs RTS to request the date. The connector in the meter is a RJ11.

    I already have a USB to RJ11 cable with a FTDI chip specifically made for this purpose.

    I was wondering if the Omega supports accessing the FTDI chip through USB. My original intention was to use the cu command but I didn't manage to get it through opkg.

    Does anybody know an alternative for it?

    Best,
    Jacinto



  • @Jacinto-Garcia said in Use FTDI cable on Omega's USB port:

    I was wondering if the Omega supports accessing the FTDI chip through USB. My original intention was to use the cu command but I didn't manage to get it through opkg.

    Omega2+ 0.1.10-b160

    root@Omega-5BE1:/# dmesg | grep usbserial
    [   11.647479] usbcore: registered new interface driver usbserial
    [   11.653625] usbcore: registered new interface driver usbserial_generic
    [   11.660403] usbserial: USB Serial support registered for generic
    [   11.718509] usbserial: USB Serial support registered for ch341-uart
    [   11.733199] usbserial: USB Serial support registered for cp210x
    [   11.748790] usbserial: USB Serial support registered for FTDI USB Serial Device
    [   11.773541] usbserial: USB Serial support registered for pl2303
    [   11.856031] usbserial: USB Serial support registered for GSM modem (1-port)
    
    # I simply connected / disconnected various USB-to-serial cables to Omega's USB host port:
    
    root@Omega-5BE1:/# [   99.098661] usb 2-1: new full-speed USB device number 2 using ohci-platform
    [   99.320340] ch341 2-1:1.0: ch341-uart converter detected
    [   99.349081] usb 2-1: ch341-uart converter now attached to ttyUSB0
    [  108.598162] usb 2-1: USB disconnect, device number 2
    [  108.603666] ch341-uart ttyUSB0: ch341-uart converter now disconnected from ttyUSB0
    [  108.611499] ch341 2-1:1.0: device disconnected
    
    [  143.798953] usb 2-1: new full-speed USB device number 3 using ohci-platform
    [  144.061183] cp210x 2-1:1.0: cp210x converter detected
    [  144.066660] usb 2-1: cp210x converter now attached to ttyUSB0
    [  151.734730] usb 2-1: USB disconnect, device number 3
    [  151.740186] cp210x ttyUSB0: cp210x converter now disconnected from ttyUSB0
    [  151.747238] cp210x 2-1:1.0: device disconnected
    
    [  164.319211] usb 2-1: new full-speed USB device number 4 using ohci-platform
    [  164.542453] pl2303 2-1:1.0: pl2303 converter detected
    [  164.569167] usb 2-1: pl2303 converter now attached to ttyUSB0
    [  170.153665] usb 2-1: USB disconnect, device number 4
    [  170.159122] pl2303 ttyUSB0: pl2303 converter now disconnected from ttyUSB0
    [  170.166240] pl2303 2-1:1.0: device disconnected
    

    Currently I have no FTDI cable handy but it should work too. ;)

    There are minicom, pyserial (miniterm), screen, stty - one of them might be good for you.

    Good luck!



  • Yes, it should work electrically, and potentially even with a simple adapter cable if you don't have a dock. The key questions would be a firmware version that is loading the appropriate driver (seems to be as indicated above) and rigging up whatever software you want to use.

    As a note, if you didn't want to use a USB-serial cable, you could just use an inverting line receiver with 3.3v output and go right into one of the omega 2's hardware UARTs. This could likely be as simple as some resistors and an NPN transistor or NFET.


Log in to reply