Quickstart Board reboots when PC GUI program starts and stops

Comments

• tdlivings Posts: 437

  2012-01-31 17:09 edited 2012-01-31 17:09

  The serial signal DTR is what is messing you up.
  The Prop boards use DTR to reset the chip.
  When I wrote a GUI using Delphi I had to tell the Async Lib I used to
  not assert DTR (Data Terminal Ready) when the GUI ran .
  The Async Lib had an option to not wiggle DTR.
  
  Tom
• pedward Posts: 1,642

  2012-01-31 17:11 edited 2012-01-31 17:11

  The PDT appears to search for a Prop on startup, at least that is what I suspect. Though the simplest answer is tdlivings.
• kvanepps Posts: 10

  2012-01-31 17:37 edited 2012-01-31 17:37

  Thanks guys for the quick reply. . I will look at disabling the DTR.
  
  Thanks
  Ken
• Toby Seckshund Posts: 2,027

  2012-02-01 00:32 edited 2012-02-01 00:32

  I usually stick in a jumper from the serial interface to the reset pin so that this can be definately stopped (if the BOE pin isn't decked then a pull up resistor will be required on the reset pin)
• Rayman Posts: 13,850

  2012-02-01 06:45 edited 2012-02-01 06:45

  I think I had trouble with that too... I don't remember if I came up with a good solution.
  But, I think you can just disconnect your usb cable before closing the comm port...
• MagIO2 Posts: 2,243

  2012-02-01 08:42 edited 2012-02-01 08:42

  Yes, for sure this helps, because the quickstart is completely out of power then .... But for sure no restart ;o)
• Rayman Posts: 13,850

  2012-02-01 10:28 edited 2012-02-01 10:28

  True. I guess that's a bit of a problem...
• tdlivings Posts: 437

  2012-02-01 10:38 edited 2012-02-01 10:38

  It is not a case of disabling the DTR serial signal in your cable or on your prop development board.
  I am saying in your code written and running on your PC, in that code do not play with DTR.
  
  I have a Delphi GUI which uses propellent.dll to download the code to the propeller before running the GUI.
  Propellent.dll I am sure wiggles DTR but my Async serial code in the Delphi code does nothing with DTR
  because I disable it's use.
  
  Tom
• kvanepps Posts: 10

  2012-02-01 17:21 edited 2012-02-01 17:21

  Well, I can see that my program is causing the DTR pin to go from high to low. I looked at it with a scope. When I stop my program (GUI written in Java), it goes back to high. I am using a JAVA API called RXTX to provide my serial interface. I tried setting the DTR to be always high and when that didn't work, I set it to be always low. Still the same thing happens which reboots the Quickstart board. I dug a little more into the RXTX Serial API and discovered there may be a bug with controlling the DTR. Not good when using it with the Propeller. I also looked at the schematic of the Propeller and saw that there is a cap (C9) between U3 pin2 of the USB/Serial chip and a transistor (Q1) which drives the reset pin low. It seems that with this circuit design the Quickstart will reboot when any change on the DTR occurs which will cause the chip to reset. If U3 pin 2 of the DTR goes from high to low or low to high, the transistor (Q1) will turn on and reset the processor. If there was enough room, the trace could be cut and a jumper put in series with the between U3 pin 2 and C9. Another idea would be just to ground the base of the transistor so that it will never turn on.....
  
  Thanks for all the feedback
  
  Ken
• obrienm Posts: 65

  2012-02-01 19:11 edited 2012-02-01 19:11

  Hi,
  The standard javax.comm library originally developed for linux but extended for win32 works fine for me, no resets. The library will not work on a 64 bit JVM but I am able to control multiple quickstart boards simultaneously from a single java process after first reloading them all using propellent in an Ant script.
  
  see http://javahardware.blogspot.com/2010/11/led-display-board-driven-by-javaxcomm.html
  and the original posts
  http://forums.parallax.com/showthread.php?119851-Writting-propeller-data-to-a-file-on-my-PC&p=879906&viewfull=1#post879906
  http://forums.parallax.com/showthread.php?109333-HowTo-Single-host-computer-and-multiple-propeller-serial-comm-and-programming&p=775612&viewfull=1#post775612
  http://forums.parallax.com/showthread.php?137636-Quickstart-Board-reboots-when-PC-GUI-program-starts-and-stops&p=1071154&viewfull=1#post1071154
  http://forums.parallax.com/showthread.php?132944-Java-comm-and-basic-stamp
  
  

  

  
  thank you
  /michael

  

  

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• Phil Pilgrim (PhiPi) Posts: 23,514

  2012-02-01 19:58 edited 2012-02-01 19:58

  This is a persistent issue with Perl PC host programs, using the standard serial interface module that diddles with DTR, no matter what you tell it to do. If anyone has a work-around for that problem, I'd be very grateful if he'd share it.
  
  Thanks,
  -Phil