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AW: AW: AW: [basicstamps] Re: serial communication — Parallax Forums

AW: AW: AW: [basicstamps] Re: serial communication

ArchiverArchiver Posts: 46,084
edited 2002-11-21 11:43 in General Discussion
> >
> >thanks very much, I thinbk I have to explain more clearly: the CMU cam is
a
> >videocam that processes data by itself and gives out serial information
> >about the RGB deviation and so on. I am not cramming whole images into
the
> >stamp.
> >
> >I tried to use the bsx but the result is almost the same.
> >
> >Some more misteries:
> >
> >When I send a command, the cmu answers with "ACK". I never get this
respond
> >when I read in the serial data. BUT when I use the stamp's WAIT command
in
> >the serin command it passes on so there must be a ACK comming but I
cannot
> >see it.
> >
> >Another question: when I read serial data into an array, for example
> >
> >INDATA VAR BYTE (10)
> >
> > by using a command like
> >
> >serin 2,baud,[noparse][[/noparse]str indata\4]
> >
> >shouldn't I get four BYTE from the incoming stream?
> >Instead I get only 8 digits, so when the camera sends
> >
> >23,211,8,45
> >
> >I will recieve
> >
> >23,2
> >
> >Does this make sense to you?
>Sure - You asked for four characters, and you got four - where's the
>surprise ?
>This presumes the commas are embedded in the data. Is that the case ? You
>may
>want to read the data in using the DEC3 modifier. I believe that the
>appropriate one to use.
>
>Seems you are right, I was thinking the cam sends a number like 225 as one
>byte, but it sends each digit as one byte.
>
>What exactly would I do with the dec3 modifier??
>It replaces the STR modifier. The manual has examples and descriptions of
all
the available modifiers and how the data is effected by each.

Going back to the question about serial data transmission speed, see if
the DM value <cr> command for the camera helps at all. The default delay
is apparently zero. You might want to try to bump it up slowly to see if
that
brings any joy.


Good hint, but I already have tried this, it makes no difference at all.
Any Idea, why the ACK doesnot show up though it must be sended because
otherwise the

serin 2,baud,[noparse][[/noparse]wait ("ACK")......]

wouldnot work?

Thanks, Uli

>Thanks a lot,
>
>Uli

Bruce


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