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RS-232 port for PE Kit — Parallax Forums

RS-232 port for PE Kit

RsadeikaRsadeika Posts: 3,824
edited 2007-02-24 16:10 in Propeller 1
I am thinking that I need to expand my PE Kit setup so I can talk to other devices via an RS-232 port. I did some searching on the Web, and I noticed Al Williams sells a neat little kit, but it needs 5V supplies. I am assuming that the Tx, and Rx pins need to be 5V, the propeller is 3.3V, so there is the problem, or am I on the wrong track with this.

I guess I need some ideas as to how to accomplish this task in the cheapest, and simplest way.

Thanks

Ray

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2007-02-23 21:55
    Look at the 2 transistor RS232 interface here (www.parallax.com/dl/docs/prod/prop/SerialtoPropeller.pdf). You don't need the 3rd transistor that provides a reset signal. You do need the 10K resistor to DTR to supply extra voltage for transmission. You can also use a MAX3232E (www.maxim-ic.com/quick_view2.cfm/qv_pk/1780) for "strictly correct" RS-232 levels. Both setups will run directly off the 3.3V supply.
  • Andy Lindsay (Parallax)Andy Lindsay (Parallax) Posts: 1,919
    edited 2007-02-23 22:46
    Ray,

    Here's a convenient idea that "should" work, but I haven't tested it yet.··The idea is to connect the·Parallax USB to Serial (RS-232) Adapter to the Propeller Plug that comes with the PE kit.

    I'll be able to let you know by Monday if nobody else has chimed in about wheather or not it works before then. You'll also need a USB cable that has the mini-b connector on both ends.

    Andy

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Andy Lindsay

    Education Department
    Parallax, Inc.

    Post Edited (Andy Lindsay (Parallax)) : 2/23/2007 10:50:32 PM GMT
  • RsadeikaRsadeika Posts: 3,824
    edited 2007-02-23 23:06
    I also came across a Serial Interface Connector that Acroname sells, it mentions that it is 3.3V tolerant. It has a DB9 on one end, and four sockets on the other end. The sockets are Gnd, Logic input, 3.3-5.0V, and Logic output, it looks like it accepts a four pin connector. Has anybody used one of these devices on a PE kit.
  • ForrestForrest Posts: 1,341
    edited 2007-02-24 00:14
    The Acroname Brainstorm RS232 level adapter works with the Propeller according to www.wulfden.org/PRC/index.shtml
  • RsadeikaRsadeika Posts: 3,824
    edited 2007-02-24 14:17
    So, I am assuming that you would just attach a seperate·wire for Tx, Rx, Gnd, and Pwr to the gadget, apply the proper sotware and the thing should work, right? If it is as simple as that, that sounds like a very neat solution, to bad Parallax does not carry a simillar item.

    On another idea, I have a BOE, and an SXxx proto board laying around. I guess I need some ideas as to how I can connect those two (or more)·up to the PE kit via comms. I hope the solution is simpler than buying a barrel full of the aforementioned gadgets.

    The direction I am heading in is having the propplug connection, a seperate RS232 connection for accessing hyperterm, and some capability to connect to·the BOE, and the SXxx proto board on seperate lines. And then hopefully I will find the example software for doing this with the BasicStamp, and the SX. This sounds like a good lesson in the PE Kit documentation.
  • ForrestForrest Posts: 1,341
    edited 2007-02-24 15:21
    The PRC-TVIO board has a 220 ohm resistors in line with the Tx and Rx pins with the Acroname Brainstorm RS232 level adapter.

    I think the PRC-TVIO board is a pretty slick/cheap ($10.50) way to add PS/2 Keyboard, Mouse, Composite video and Audio out in addition to the Brainstorm interface. It looks like the PRC-TVIO board will attach to your PE breadboard if you install the (2) female headers for 3.3V, 5V and GND on the top side of the board and run 3 wires from the female headers to the PE breadboard. Check the assembly documentation for the PRC and TVIO board here www.wulfden.org/PRC/PRC200-2.pdf and if you have questions - contact Brian Riley directly (link at the top of the PRC web page).

    FYI I'm not associated with Brian - I'm just a satisfied customer.
  • RsadeikaRsadeika Posts: 3,824
    edited 2007-02-24 16:02
    Thanks Forrest for the info, it looks like the PRC is a very good product, but to much soldering for me. I do not mind soldering a few points, but not to that extent that is required for the board(s). I had a heck of a time getting the headers soldered up on my SXxx proto boards, way to much tedius work. ·Now hopefully their will be a cheap solution to the problem at hand, with no soldering.
  • ForrestForrest Posts: 1,341
    edited 2007-02-24 16:10
    If you don't want to do any soldering, then (2) 220 ohm resistors, a few wires and a 4 pin male header pressed into your breadboard will let you use the Acroname Brainstorm RS232 level adapter
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