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How do I prevent the propellor from restarting when a serial program closes? — Parallax Forums

How do I prevent the propellor from restarting when a serial program closes?

brandanbrandan Posts: 52
in Propeller 1
I'm using ubuntu. Is there a way to prevent that by, changing something on the propeller or on the program settings?

Comments

  • mikeologistmikeologist Posts: 337
    Is the serial connection through the propellers usb port?
    If so have you tried making it on different pins?
  • VonSzarvasVonSzarvas Posts: 3,450
    How are you connecting the propeller to your computer? Usb?

    And what's the circuit... Custom or Parallax board?

  • brandanbrandan Posts: 52
    I'm using an activity board and I'm connected via usb.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    The problem is likely to be that your Ubuntu serial program signals DTR when it closes. This is what resets the Prop. Can you configure the serial program not to do this? If there's a "no handshaking" option, selecting it may be all you need to do.

    -Phil
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    As an addendum to the above, you can reprogram the USB chip on the Activity Board not to send the DTR to its port pin that controls /RST. But in order to reprogram the Prop, you'll have to switch it back.

    -Phil
  • msrobotsmsrobots Posts: 3,709
    Or you need to cut the traces from usb to /reset and put a jumper there. Something that is missing on most parallax boards.

    Sadly,

    Mike
  • brandanbrandan Posts: 52
    I solved my problem
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    brandan wrote:
    I solved my problem
    Ok, how? One of the benefits of this community is sharing not only problems, but solutions.

    -Phil
  • brandanbrandan Posts: 52
    I turned off DTR
  • ElectrodudeElectrodude Posts: 1,657
    For anyone wondering how to do it via command line: 
    stty -F /dev/$DEVICE $BAUD -hup cbreak
    seems to do the trick. The `-hup` disables DTR when the last program on the serial port closes, and the `cbreak` makes it not EOF whenever there's nothing in the PC's receive buffer. This makes it possible to use `cat` and friends to operate on the serial port directly without needing a serial port program.
  • tomcrawfordtomcrawford Posts: 1,126
    @brandan

    In your icon, green varies vertically and red varies horizontally. How is blue calculated?

    Oops! Didn't mean to highjack the thread; the devil made me do it.
  • mikeologistmikeologist Posts: 337
    edited 2017-12-03 06:38
    .
  • Beau SchwabeBeau Schwabe Posts: 6,566
    edited 2017-12-03 22:20
    You must have RevA ... I think RevB and RevC attempt to correct the problem with U14 and U15. This problem existed several years ago when I worked at Parallax and there was a software fix by forcing the TX line from the Propeller HIGH or LOW... I can't remember which... what is happening is that without power, the FTDI defaults to a mode that resets the Propeller. By forcing the TX line from the Propeller HIGH (<- I think that is correct)... the FTDI has enough parasitic power to prevent a reset.


    EDIT: Hmmm... I just noticed in the schematic that the enable for U14 and U15 buffer is not connected to anything or is a no-connect ... it should be connected to the +3.3V from the USB power to enable it when USB power is applied. ... it's possible it has an internal pullup however



    RevA:
    RevA.png

    RevB,C
    RevB_C.png
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