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Programming the Prop Mini — Parallax Forums

Programming the Prop Mini

dennodenno Posts: 223
in Propeller 1
Question...can I use the USB to serial adaptor that is used to program the Basic Stamps, to program the Prop Mini, if I reconfigure the Rx,Tx,Vcc and ground to match the pins on the Prop Mini, instead of having to buy the "Prop plug" for $16..??

Thank you...denno

Comments

  • iseriesiseries Posts: 1,492
    The problem is that the Propeller chip is 3.3 volt and the Basic Stamp is 5 volts so the converter will drive the pins to 5 volts and not the 3.3 volts the propeller wants. There is also a reset circuit connect to DTR to reset the propeller during programming.


    Mike
  • Cluso99Cluso99 Posts: 18,069
    iseries wrote: »
    The problem is that the Propeller chip is 3.3 volt and the Basic Stamp is 5 volts so the converter will drive the pins to 5 volts and not the 3.3 volts the propeller wants. There is also a reset circuit connect to DTR to reset the propeller during programming.


    Mike
    Check out the PropPlug schematics.

    I use the CP2102 USB 6pin version (~$1.50) There is a link in my P8XBlade thread, which also powers my board (5V). Do NOT use the 3V3.
    So, you will require the DTR transistor reset circuit - some manage to get away with using just a capacitor instead but it’s a case of try and see as it may not always work reliably. You will also need to regulate the 5V to 3V3.
    I have both the transistor reset circuit and 3V3 regulator on my boards.
  • dennodenno Posts: 223
    Very good...thank you for the input..I will just go ahead and purchase the Prop Plug. It is just that, I have several USB to Serial for the basic stamp, as I have been doing embedding for as long as the stamp has been out there...and now, switching over to the Prop, using Propbasic....been doing a learning curve with the FLIP..which is a great device...my favorite in days gone buy was the BS2sx....Thanks to all..Denno
  • Wuerfel_21Wuerfel_21 Posts: 5,053
    If you have a nice switch to hook up to the reset pin, you can also do without the reset circuit. It takes a little while to get the timing down though.
  • dennodenno Posts: 223
    well, I ordered the Prop Plug, anyways...it was just a thought on being able to program the Prop Mini with the USB to Serial adaptors I already have for the Basic Stamp. On another note/question, on the Prop Mini, can P30 and/or P31 be used as a regular I/O, once the programming is complete. I guess the question could be restated, as soon as the program is downloaded to the Prop Mini, and in the program I elect P30 and P31 to be OUTPUTS, they will be OUTPUTS, when the Prop Plug is removed. I have assigned all the rest of the I/O's for various tasks, and need only one more I/O.

    Thanks...denO
  • PublisonPublison Posts: 12,366
    The only thing I would be careful of; is when you Program the Prop, either RAM or EEPROM, the program is going to run right away. You don't want Prop outputs driving PropPlug inputs.
  • dennodenno Posts: 223
    Sooooo...unplug the Prop Plug quickly? Thank you...Publison
  • iseriesiseries Posts: 1,492
    What? I leave my prop plug plugged in all the time. That's where the terminal interface comes in. I also use a Parallax WX WiFi in place of the Prop plug if I want to program it remotely or use a WiFi connection.

    Mike
  • hatallicahatallica Posts: 175
    Regarding Pins 30-31 ... yes they may be used with due diligence.

    When feasible, I keep these assigned serial devices (i.e. Parallax Serial LCD #27979). During programming, the LCD displays garbage characters, which is easily remedied. Make sure that your arrangement similarly causes no harm.
  • dennodenno Posts: 223
    Thanks for your help hatallica...after programming, I will simply pull the prop plug...and let the program run...If I need to reprogram I will first turn off the Vcc and insert the prop plug, and repower, and reprogram. I believe once reset is activated during reprogramming of the prop mini, there will not be a problem with (lets say P31) having been declared as an OUTPUT in the the program..during the reprogram..I don't know about everyone, but generally, when I write code for an embedded device, I end up reprogramming, over and over and over, until I get the device to do what I want it to do...with the program (source code).

    Thanks..dennO
  • msrobotsmsrobots Posts: 3,709
    you should try to rearrange your pin settings or at least put a diode between prop plug and pin to prevent outputs hitting each other.

    At power up the P1 loads the program from EEPROM faster as you can hit the program button so before you are able to reprogram your old program is already running.

    so like @hatallica said, be careful of what you are using the pins for.

    Mike
  • Cluso99Cluso99 Posts: 18,069
    IIRC the PropPlug has series resistors which will prevent damage if both pin ends output against one another.
  • dennodenno Posts: 223
    Another question please...I received my Prop Mini and the Prop Plug today. I noticed on the Prop Plug bag, the words "STOP! INSTALL SOFTWARE FIRST" install USB VCP Drivers...

    Well I have already been working with the FLIP and Propbasic on/with several programs using this computer. If I am already downloading programs into the FLIP, do I have to download more drivers to program the Prop Mini?

    Thanks..DennO
  • TubularTubular Posts: 4,702
    No, it'll be fine - it'll find the ftdi driver

    I think that comment was more applicable to older operating systems
  • dennodenno Posts: 223
    Thank you Tubular...
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