detecting string from RS232 tx line

Projects Interfacing w/ Software on the Computer
1

I am very green when it comes to the comms between a PC and Arduino.

I have made a few display units to show the value of a string, that I receive from a usb /ttl converter.

I have used the Terminal software for testing, to send from the Arduino embedded chip in the display.

The string #002#031123456#003 displays 1234566 on the display.

I was given a similar display to repair, I assumed it also needed a usb/ttl converter ( which worked fine when I fixed the pcb ) , but I was told it just needs 2 wires to connect to RS232.

It had been connected with just 2 wires ( gnd and RXin ? ) to a RS232 9 pin socket - and had been working at some time.

I made a simple inverter/level shifter to convert the PCs RS232 Tx signal to 5v inverted data, but when I search for available ports on the terminal page, it just finds port 1 and 3 ( which I assume is the usb mouse )

I can unplug the 9pin connector and it makes no difference, it stills can find only 01 and 03.

I presume it needs the duplex to find the right ports available ?

2

Boffin1:
I have made a few display units to show the value of a string, that I receive from a usb /ttl converter.
...SNIP.....

I was given a similar display to repair,

You may know something about these, but we can't help you unless you share your knowledge with us.

For the devices you made yourself, I presume there is no datasheet that you can provide a link to. But maybe there is for the "similar display"?

...R

3

When you say:

I presume it needs the duplex to find the right ports available ?

What is the 'it', that you talk about?

If I make a wild guess, is 'it' a computer, then what sort of operating system are you using, GNU/Linux OS-X or that other one?

Then additionally:

I can unplug the 9pin connector and it makes no difference, it stills can find only 01 and 03

Are you unpluging from the 'it' thing or something else?

which I assume is the usb mouse

Where on Earth does USB come into the picture now?

What ever 'it' is, the asnyc ports the system finds should not be dependant on having equipment connected to 'it', rather the UART hardware in 'it'.

Paul

4

Thanks guys

When I had made the usb versions of these displays, Terminal had to find the port, but of course using the 9 pin din socket it is COM1.

I scoped the output of my inverter and the waveform was there when I sent the string.

The string should have been #002#032123456#003 ( the 032 is space in ascii ) and when I corrected that it worked.