News from Mac OSX - Mysterious Serial Port

[Dar Scott]

On Thursday, August 21, 2003, at 01:35 PM, R. Hillen wrote:
>
> -----
> on mouseup
>   put "/dev/cu.gPort" into DriverName
>
>   put "BAUD=9600  PARITY=N  DATA=8  STOP=1" into serial
>   set the serialControlString to serial
>
>   open driver DriverName for text update

There are a few bugs on OS X.  I found the best success with binary 
update with LF line-ends.

>
>   if the result is not empty then
>     answer the result
>   end if
>
>   write fld SendField  & linefeed & return to driver drivername
>
>   close driver drivername
>
> end mouseup
> -----
>
> To read the sent serial data I used a Windows Hyperterminal running on 
> a Win-Laptop.

Double check settings and handshaking for this.

>
> What happened:
>
> I typed "12345" into field SendField, pressed button "Send" and got 
> garbage in the terminal, 1 or two chars, nothing of "12345".
>
>
> I typed "1234567890" and got two garbage chars
> I again typed "1234567890" and got two garbage chars

At first glance, this looks like mismatched bit rate, but...

> I again typed "1234567890" and got about 12 garbage chars.
>
> This cycle was repeatable.
>
>
> I typed "1234567890123456789012345678901234567890 1234567890" and got:
> "12345678901234567890123456789012345678901234567890", followed by 
> NewLine.
>
> After that, I tried again with "12345" and got garbage (see above)

This is weird.

I'd make sure the ground is wired.  The long lines working better than 
short seems to indicate this.

You might also have a ground loop.  Try unplugging the laptop from 
other things.

Is the gPort really RS-232?  Maybe you have level problems.  If it is 
RS-422, you might be OK, but there might be problems depending on the 
wiring.  If it is MIDI, I'm amazed you saw anything.

> I dont know at this time, if it is a revolution- or a griffin-problem.
> Next I will bugzilla it.

There are a few Revolution problems, but there seems to be something 
here beyond them.

> I hope to get next week a USB2Serial adapter with OSX-drive, so I will 
> try again.
> Probably someone of you may test it also?

I will test on Revolution any serial devices that show up on my 
doorstop and report to all interested.  Those accompanied by chocolate 
will be tested first.  :-)

Dar

****************************************
     Dar Scott Consulting
     http://www.swcp.com/dsc/
     Programming Services
****************************************