No serial port console



  • Build 0.1.9 b149
    Arduino mother board (don't get the silicon labs device, not sure if I should).
    FTDI converter connected to serial port pins (it works on TX1 from the big connector)
    Issues:
    Serial port pins on the side (TX0) get nothing. In fact the TX pin is sitting a 0V (should be high).
    The fact that is is at 0V says that either the HW is dead, or it never got set up.
    Echoing to /dev/ttyS1 sends data out at 9600 baud on TX1, but S0 is dead.
    (See reply below for solution)



  • It's probably worth investigating the dock and omega separately.

    Typically on an MT7688 design TX0 and also sometimes TX1 will have pulldown resistors, as the chip determines it startup mode by looking for these - the TX0 pulldown tells it to go into operational mode rather than a testmode, for example.

    But of course while a pulldown resistor can make an un-driven line look grounded, it's a very different thing from a possible short of the line to ground, perhaps you can figure out which you have.


  • administrators

    The Arduino Dock 2 does not come with a USB to serial chip.

    The serial connector on the Arduino Dock 2 is connected to ttyS0 on Omega which by difficult is set to be serial terminal at 115200 baud.

    You can get to Omega's serial terminal by using an external USB to serial adaptor like this:
    0_1486597359451_IMG_20170208_183434 copy.jpg
    0_1486597387841_IMG_20170208_183422 copy.jpg

    0_1486597392506_Screen Shot 2017-02-08 at 6.30.54 PM.png



  • @J-D The solution is that the Arduino Dock had a dead short (ohm meter, 0 ohms) to ground on the TX0 line.
    I cut the pin and soldered a wire right to the board, and now it works.
    I looked at the schematic, and no, the mini-usb does nothing but provide power.
    Also, the 3 pins on the side connect to a mux that switches between the console on TX0 and the ATMEGA serial port, the Omega has to give permission by raising IO19 to program the ATMEGA.
    Hard to believe another 3 pins could not have been added, to making it easier to program the Arduino. Also, for the price a serial to USB adaptor should be there, instead of the analog mux. 7.00 china Arduino knockoffs use a low cost serial to USB chip that works just fine (CH340).



  • I also have a problem with Arduino Dock 2 and an FTDI adapter. The Arduino Dock 2 turns on (blue led on), but
    the Omega 2+ doesn't turn on. I have connected my FTDI adapter as in the photos above. What could be wrong?


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