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Communication to Propeller Chip — Parallax Forums

Communication to Propeller Chip

ArdeArde Posts: 4
edited 2009-05-29 15:30 in Propeller 1
Hello All,

I am using the demo board to write a serial communication program. It works fine when I use Hyper Terminal.

However When I use other serial programs, when I send a string the board reboots!

I am connected via the USB cable from a PC to the Demo board.

What I am doing wrong?


Thanks,

Arde

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2009-05-26 18:17
    The Propeller Tool uses the DTR line to force a reboot of the Propeller so it can download a new program. You probably have HyperTerminal configured so it does not toggle DTR when it opens the serial port. When you use other serial programs, they probably toggle DTR when they open a serial port. You have to change their configuration setup so they don't change DTR when they open or close a serial port. Check the documentation for the programs you're using.
  • ArdeArde Posts: 4
    edited 2009-05-26 18:30
    Hi Mike,

    Thanks for you reply.

    Using Hyper Teminal all I did was to disable "Hardware Handshaking". The same thing I did using the other Serial Tools.

    If the DTR line is forcing high, is there anything I can do on my side to prevent this from happening?

    Thanks.
  • Mike GreenMike Green Posts: 23,101
    edited 2009-05-26 18:59
    Because the USB to serial adapter is built into the Demo Board and the DTR signal is not really accessible, there's nothing you can do on the Propeller end. You really have to disable the use of DTR by the program involved and the details of that vary from program to program. Disabling "hardware handshaking" often will work, but that depends on the program.
  • Toby SeckshundToby Seckshund Posts: 2,027
    edited 2009-05-26 19:58
    I always put a pull up resistor on the prop side and route the reset from the serial thru a jumper.
  • ArdeArde Posts: 4
    edited 2009-05-26 20:18
    Hi Toby,

    Can you please give a little bit more detail as where to put this Pull Up Resistor and the route?

    Thans.
  • Mike GreenMike Green Posts: 23,101
    edited 2009-05-26 20:39
    This is not something you can do on the Demo Board or on the USB Protoboard without some very delicate soldering and cutting of traces. I wouldn't recommend it.
  • StefanL38StefanL38 Posts: 2,292
    edited 2009-05-27 19:17
    It will be much easier to set up a second serial connection on any other pins than pin 30,31

    a PC-comport uses +12V -12V voltage-levels the propeller has 0V/ 3,3V best thing is to use a MAX3232
    which is build for shifting voltage-levels exactly between 0V/3,3V and +12V/-12V

    The other way is to use PST.EXE from Parallax which does NOT toggle the DTR-line when opening the com-port

    best regards

    Stefan
  • ArdeArde Posts: 4
    edited 2009-05-29 15:30
    Stefan,

    Thank you for your help. I implemented your suggestion with MAX3232 and I was surprised as to how easy it was to get it working.

    Thank you again.
    ·
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