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Serial problems (solved) — Parallax Forums

Serial problems (solved)

computer guycomputer guy Posts: 1,113
edited 2008-04-23 05:00 in Propeller 1
I have a "matchport b/g" connected to a propeller and they will not communicate.

The propeller is running FullDuplexSerial and I have tried all of the modes (0-3) and it is set for 9600 baud.

The "matchport b/g" is configured for the following.

RS232
8 bits
1 stop bit
no flow control
9600 baud

Using my Parallax USB Oscilloscope I have determined that they are going from (logic level) high to low fine. (3.3v to 1.7v aprox)

I can get both devices to talk to the PC via a prop plug but not to each other.

Does anyone know what might cause this?


Thank you smile.gif

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Check out my robot using the propeller RECONAUTOR
If you like my avatar then check this out Propeller Domed Stickers for sale

Building Blocks To The Propeller Chip

Post Edited (computer guy) : 4/23/2008 3:20:59 AM GMT

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2008-04-23 01:52
    Perhaps you have receive and transmit backwards?· The first pin number in FullDuplexSerial.start is the receive pin # (from the MatchPort) and the second pin number is the transmit pin # (to the MatchPort).

    Logic low should be lower than 1.7V.· That may be a sign that you have things reversed.
  • Bob Lawrence (VE1RLL)Bob Lawrence (VE1RLL) Posts: 1,720
    edited 2008-04-23 01:53
    Is this the hookup you are using?

    =============================================================

    Serial Interfaces
    The MatchPort b/g serial interface is 3.3V logic level and typically connected to a
    Universal Asynchronous Receiver/Transmitter (UART). For connection to an external
    device, the demo board has RS-232/422/485 transceivers. CON1 and CON2 support
    RS-232/485. Connect to a PC using a null-modem serial cable with 9-pin connectors
    (F/F).
    The table below lists the RS-232 signals and corresponding pins on the MatchPort
    b/g. All signals are level-shifted by the RS-232 transceivers

    Table 3-1. RS-232 Signals
    MatchPort b/g
    PIN FUNCTION
    DB9
    Pin #
    UART x Conx

    http://www.lantronix.com/pdf/MatchPort_IG.pdf
    TXDx (Data Out) 3
    RXDx (Data In) 2
    CTSx (HW Flow Control Input) 8
    RTSx (HW Flow Control Output) 7
    DCDx (Modem Control Input) 1
    DTRx (Modem Control Output) 4

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    Aka: CosmicBob
  • computer guycomputer guy Posts: 1,113
    edited 2008-04-23 02:22
    I have checked the pins and am sure that they are around the right way.

    I have the following connections.

    Matchport **** PropPlug

    TX

    > RX
    RX <
    TX
    GND <
    > GND

    OR

    Prop **** PropPlug

    TX(P26) ----> RX
    RX(P27) <---- TX
    GND <

    > GND

    OR

    Matchport **** Prop

    TX

    > RX(P27)
    RX <
    TX(P26)
    GND <
    > GND


    *Doesn't work
    *Works

    Thank you smile.gif

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Check out my robot using the propeller RECONAUTOR
    If you like my avatar then check this out Propeller Domed Stickers for sale

    Building Blocks To The Propeller Chip

    Post Edited (computer guy) : 4/23/2008 2:28:20 AM GMT
  • computer guycomputer guy Posts: 1,113
    edited 2008-04-23 03:18
    Some of you may not get this. smile.gif

    I wound the window down and up a few times and now it works.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Check out my robot using the propeller RECONAUTOR
    If you like my avatar then check this out Propeller Domed Stickers for sale

    Building Blocks To The Propeller Chip
  • Jesse DruehlJesse Druehl Posts: 25
    edited 2008-04-23 04:10
    braypp terminal?

    Jesse
    W5JCD
  • computer guycomputer guy Posts: 1,113
    edited 2008-04-23 05:00
    Jesse,

    Assuming you are asking if I am using braypp terminal.
    I use Putty or Hyper Terminal for serial coms. smile.gif

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Check out my robot using the propeller RECONAUTOR
    If you like my avatar then check this out Propeller Domed Stickers for sale

    Building Blocks To The Propeller Chip

    Post Edited (computer guy) : 4/23/2008 5:38:06 AM GMT
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