DPRG mailing list archives: [DPRG] Serial Woes

Sat Feb 3 09:45:08 CST 2007

Hmmm.

Does the Acroname serial interface controller get its power from the
serial port itself, like from the DTR signal, or is it separately
powered?

I agree with Ron that an RTS-CTS connection may have to be made if
somehow hardware handshaking is involved.

A very useful device I built some time ago has two  9-pin serial
connectors on a piece of perf board with a hex inverter, a MAX232
chip, and some jumpers. With it, you can jumper select TX and RX on
each port to either pin 2 or 3, and can also jumper an inverter on the
logic side of each gate.  I built this little beasty back when I was
getting lots of serial port-generated headaches.

It sounds to me like you're past this part, though.  (If you want to
borrow the device, let me know.)

Some time ago, when I was having trouble talking to Handyboards and
MIT 6.270 boards via a serial port, Steve Rainwater and David Anderson
suggested using Miniterm under Linux.  It turned out that that
particular problem was caused by Window's Hyperterminal.

-Jeff

On 2/2/07, Eric Sumner <kd5bjo at gmail.com> wrote:
> I am trying to connect a Parallax servo controller
> <http://www.parallax.com/detail.asp?product_id=28023> to a computer
> using an Acroname serial interface connector
> <http://acroname.com/robotics/parts/S13-SERIAL-INT-CONN.html>.
> Unfortunately, no matter how I try to hook them together (including
> using resistors, diodes, transistors, and logic gates in various
> configurations), I end up with one of two situations:
>
>   * The computer can see everything it sends out to the serial port,
> and the servo controller crashes whenever there is any serial
> activity, or
>   * The servo controller works, but the computer can't read back any
> of the responses that the serial controller is giving.
>
> In neither case is there anything obviously wrong with the control
> signal.  Any ideas?
>
>   -- Eric
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