From: "Matt Foster"
Subject: Re: RS232 newbie - in need of assistance!
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Date: Fri, 03 Jan 2003 12:46:34 GMT
NNTP-Posting-Date: Fri, 03 Jan 2003 12:46:34 GMT
Organization: blueyonder (post doesn't reflect views of blueyonder)
Hmm no code, sounds easy - but expensive?
Here's my basic request then (I figured I need 5 switches now)
5 push to make switches, (say 1,2,3,4,5), when switch 1 is pressed, I'd like
the screen to say "1" and the same for 2 3 4 5.
The final thing will be a bit more complex oin the software side, all I need
the hardware to do is send one of 5 characters (they can be anything) to the
serial port (does it need to be followed by a line feed or anything?) so
that the program can recognise what was pressed.
If it's simple and possible, then I'd like the PCB to filter out which
button was pressed first out of 1,2,3 and 4 - then not accept any more
inputs until switch 5 is pressed (a reset). But I can do this software side
"John Fields" wrote in message
> On Thu, 2 Jan 2003 19:00:52 -0000, "Matt Foster"
> >I am an A-Level student looking to read computer science at university in
> >the coming years.
> >As a project I am trying to design a circuit that transmits data to the 9
> >pin serial port (RS232) of a standard PC.
> >As a basic start I am trying to make a circuit with 4 ptm switches, when
> >press switch 1 I would like to display "switch 1" or somesuch on the
> >computer screen. The same for switch 2,3 and 4.
> >I will be using VB and the MSCOMM control to access the serial port, and
> >forsee no problems with doing this. My hurdle, however, is sending the
> >'data' from the PCB to the serial port.
> If you're interested in doing it in hardware (CMOS or TTL, no µC)
> post a request here and I'll work something up for you and post it
> to alt.binaries.schematics.electronic. sometime this weekend. I'm
> thinking two HC165's and a single TTL-to-RS-232 converter to send
> the data into the PC's serial port, an HC191 to frame the word, a
> 7555 clock and maybe a little glue logic to hold it all together.
> Prob'ly 6 chips by the time it's all done, but it'll be standalone
> and you won't have to write any code to run it.
> John Fields
> Professional circuit designer
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