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Will this work? — Parallax Forums

Will this work?

Jack3Jack3 Posts: 55
edited 2014-01-29 15:05 in Propeller 1
I have a couple mini B/USB adapters, with FTDI chip FT232RL,
outputs: gnd, cts, vcc, tx, rx, dtr

I do not have a prop plug, but I do have an integrated board, I want to do this all on the breadboard as per the BOE manual
My assumption is that I use the (gnd, tx, rx, and dtr) pins, with tx going to rx on the Prop, and rx to tx, and dtr to reset. (This is as per my interpretation -of the drawing in the manual showing the Prop tool, eeprom, clock, and chip.

Is this a viable solution?

Comments

  • AribaAriba Posts: 2,690
    edited 2014-01-28 18:53
    It may work for programming the Propeller, but you get problems if you want to comunicate with a Terminal or other applications on the PC.
    If you want to do it right then add the R-C-Transistor circuit between DTR and Reset (first circuit in the picture).
    FT232Conn.gif

    If you don't have the parts you can also add only a series capacitor and invert the DTR output of the FT232 with the help of the PC-Tool: FT_Prog.

    Andy
    FT232Conn.gif
    250 x 262 - 2K
  • Peter JakackiPeter Jakacki Posts: 10,193
    edited 2014-01-28 19:15
    Ariba wrote: »
    If you don't have the parts you can also add only a series capacitor and invert the DTR output of the FT232 with the help of the PC-Tool: FT_Prog.

    Andy

    Since it's only needs an edge to reset you don't even need to invert the DTR as I have gotten by with just a 1,000pF (or more) cap from the FT232 to the Prop's reset.
  • AribaAriba Posts: 2,690
    edited 2014-01-28 19:29
    If an application drives the DTR pin then the DTR output of the FT232 goes low on COM open and back to high on COM close. This has the effect that you get a Reset when the COM opens - not good if you have loaded the Propeller code to RAM. With inverted DTR the Reset happens when the COM port gets closed, and that is normally not a big problem.

    With the Propeller code in EEPROM both should work.

    Andy
  • AribaAriba Posts: 2,690
    edited 2014-01-28 19:38
    Jack3

    I forget:
    Make sure that the FT232 adapter works with 3.3V levels otherwise you need to add a series resistor (~2.5k) between the TX and P31.

    Andy
  • Jack3Jack3 Posts: 55
    edited 2014-01-29 05:24
    Ariba,
    Yes, the adaptor has a choice between 3.3 and 5

    I am still a beginner, what is the 1n, a capacitor?
  • AribaAriba Posts: 2,690
    edited 2014-01-29 05:50
    1n = 1 nanoFarad = 1000 pF = 0.001 uF

    The value is not that important, I would say something in the range of 0.5 ... 10 nF (nano farad)

    If you want to build the first circuit:
    10k = 10 kiloOhm resistor
    NPN = a general purpose NPN Transistor like 2N3904

    Andy
  • Jack3Jack3 Posts: 55
    edited 2014-01-29 09:06
    Thanks Andy, I just am not good in the capacitor stuff yet, I get confused with all the numbers and symbols, I have the 2N3904 and I think I have a cap that will suffice.
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2014-01-29 09:21
    There is always this old standard...SerialtoPropeller.pdf

    It works quite well with RS232 from a USB to RS232 adapter.
    pdf
    pdf
    SerialtoPropeller.pdf
    62K
  • Jack3Jack3 Posts: 55
    edited 2014-01-29 15:05
    Well, yes it works now, I went through so much bizarre stuff, but am there now with my flashing little LED....coollllll
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