Serial flow control basics...
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Hello Stampers,
Can anyone please point me to a basic explanation of the correct use of flow
control lines such as CTS-DTR-RTS etc. I have Jan Axelsons "Serial Port
Complete", but it doesnt really say what I need to know.
I would like to know how to correctly set up a serial flow control with my
stamp, fully usng all flow control lines. i know that this is not always
necessary, but I would like to learn the basic corect procedure.
Cheers,
Chris - Western Australia
Can anyone please point me to a basic explanation of the correct use of flow
control lines such as CTS-DTR-RTS etc. I have Jan Axelsons "Serial Port
Complete", but it doesnt really say what I need to know.
I would like to know how to correctly set up a serial flow control with my
stamp, fully usng all flow control lines. i know that this is not always
necessary, but I would like to learn the basic corect procedure.
Cheers,
Chris - Western Australia
Comments
'RS232 Made Easy' -- see
http://www.bb-europe.com/dept.asp?dept%5Fid=7
The EIA-RS232 standard itself is also very helpful.
Basically, 232 was for a computer (DTE --
Data Terminal Equipment) to talk to a Modem (DCE --
Data Communication Equipment). So the hardware
handshake signals are based on this.
RTS == Ready To Send -- DTE saying it has a byte
CTS == Clear To Send -- Modem saying it's alright to
send a byte.
RTS/CTS thus provide a byte-level handshake.
DTR == Data Terminal Ready -- DTE saying it's ON.
-- If you Drop this, it tells the modem to HANG UP.
DSR == Data Set Ready -- Modem saying it's ON.
DCD == Data Carrier Detect -- Modem saying it
has connected with the far-end Modem, and is ready
to send/receive data.
Additionally, in PC's:
RI == Ring. The Modem telling the DTE the phone
is ringing. This also can trigger the PC's
serial port interrupt.
--- In basicstamps@yahoogroups.com, Chris Anderson <fuel@b...> wrote:
> Hello Stampers,
> Can anyone please point me to a basic explanation of the correct
use of flow
> control lines such as CTS-DTR-RTS etc. I have Jan Axelsons "Serial
Port
> Complete", but it doesnt really say what I need to know.
>
> I would like to know how to correctly set up a serial flow control
with my
> stamp, fully usng all flow control lines. i know that this is not
always
> necessary, but I would like to learn the basic corect procedure.
>
> Cheers,
> Chris - Western Australia
8 signals (TX/RX, RTS/CTS, DTR/DSR-DCD, RI)
you'll need 3 TTL to 232 transmitters
(TX data, RTS, and DTR) and up to 5
232 to TTL receivers (on a stamp, this can
be a 22 KOhm series resistor) RX, CTS,
DSR, DCD, and RI.
--- In basicstamps@yahoogroups.com, Chris Anderson <fuel@b...> wrote:
> Hello Stampers,
> Can anyone please point me to a basic explanation of the correct
use of flow
> control lines such as CTS-DTR-RTS etc. I have Jan Axelsons "Serial
Port
> Complete", but it doesnt really say what I need to know.
>
> I would like to know how to correctly set up a serial flow control
with my
> stamp, fully usng all flow control lines. i know that this is not
always
> necessary, but I would like to learn the basic corect procedure.
>
> Cheers,
> Chris - Western Australia