Multiple serial communications
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Posts: 46,084
I'm building a data collection system. I have multiple RS232 devices
(commercial products that can't be altered) that need to connect to
the basic stamp and the basic stamp needs to connect to a computer.
There are also several other relays, switches, etc. that the basic
stamp needs to interface. The problem is how to handle three or more
simultanious (or nearly simultanious) serial connections with the
basic stamp. Any ideas?
(commercial products that can't be altered) that need to connect to
the basic stamp and the basic stamp needs to connect to a computer.
There are also several other relays, switches, etc. that the basic
stamp needs to interface. The problem is how to handle three or more
simultanious (or nearly simultanious) serial connections with the
basic stamp. Any ideas?
Comments
serial ports "at once", as long as they don't send data at the same time.
When the Stamp is receiving data (via Serin), that's all it is going to do.
The other serial devices can send all the data they want, and the Stamp
will ignore them.
Now, if the external devices only send data when they are asked to by the
Stamp, then you don't have a problem, as you can handle them one at a time,
although on separate pins.
If you really need to handle several simultaneous serial data streams, you
will probably have to use a coprocessor, such as a PIC, or maybe even
several PICS, and have them store the data until the Stamp can handle it.
Larry
At 06:15 PM 4/19/2003 +0000, you wrote:
>I'm building a data collection system. I have multiple RS232 devices
>(commercial products that can't be altered) that need to connect to
>the basic stamp and the basic stamp needs to connect to a computer.
>There are also several other relays, switches, etc. that the basic
>stamp needs to interface. The problem is how to handle three or more
>simultanious (or nearly simultanious) serial connections with the
>basic stamp. Any ideas?
>
>
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Larry Bradley
Orleans (Ottawa), Ontario, CANADA
The Maxim 3110 is a 28-pin narrow dip, which comes
with a hardware UART (TX and RX), and 2 232 drivers,
and 2 232 receiver gates.
It does need a 3.8 Mhz crystal, and two 10 pF caps
for the Baud generator circuit.
It has a 3-wire interface (SPI) to the Stamp.
It has an 8 character input buffer -- which is quite
small for Stamp use, really.
You can set up one of these per port, and have a tight
loop which samples each one to find if it has recieved
one or more bytes.
There do exist solutions which use a PIC, and have much
larger receive buffers, but I have found the 3110 to
be a very simple and reliable way of having the stamp
do something else most of the time, and check the
buffer every so often.
--- In basicstamps@yahoogroups.com, "selket_10027"
<selket_10027@y...> wrote:
> I'm building a data collection system. I have multiple RS232
devices
> (commercial products that can't be altered) that need to connect to
> the basic stamp and the basic stamp needs to connect to a
computer.
> There are also several other relays, switches, etc. that the basic
> stamp needs to interface. The problem is how to handle three or
more
> simultanious (or nearly simultanious) serial connections with the
> basic stamp. Any ideas?