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usb BOE board rev B as a second com port with propeller proto board on top — Parallax Forums

usb BOE board rev B as a second com port with propeller proto board on top

winterbottom321winterbottom321 Posts: 3
edited 2011-02-09 22:47 in Propeller 1
I've got a propeller proto board using the onboard serial for programming. I stacked this board on top of a BOE board rev B which has a usb ft232bl chip on it. Stamp chip is pulled. I want to use this second board only for an extra com port to debug to.

I ran a 3 wires down: two pins on the prop (8,9) and into the Sout Sin pins where the stamp would normally go and vss tied from each board. I've got the drivers installed but everything is still coming out garbled in the terminal window. I've tried 200 to 9600 baud. All are garbled. I've tried using fullduplexserialplus as well as bs2_functions and both come out garbled. Am I missing something here?

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2011-02-09 21:34
    Two things ...
    1) The Stamp normally uses inverted serial I/O for programming because it's designed to attach to an RS232 port which uses inverted signals

    2) The USB adapter on the BOE produces 5V signals which can destroy Propeller I/O pins.

    You can put a 2.2K resistor in series with the Rx and Tx lines to the BOE and that will protect the Propeller I/O pins. You can set the mode bits in the start call to FullDuplexSerial to invert the serial I/O signals. That should let it work properly.
  • winterbottom321winterbottom321 Posts: 3
    edited 2011-02-09 22:47
    Wow! You are great. Working like a champ now. How handy it is to use two com ports.

    I'm glad the 5v didn't make my prop go up in smoke.
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