AT Commands and RS232
#1
Posted 07 January 2011 - 11:03 AM
#2
Posted 07 January 2011 - 08:35 PM
#3
Posted 08 January 2011 - 12:38 PM
Hi StefanoZ,
First of all, are you using an RS232 expansion shield for the Netduino? The D0/D1 pins (COM1) are 0/3.3V, not -12V/12V like RS232...
Also, could you please provide a bit of guidance on how you're wiring the two together? There should be three pins (Netduino TX to phone RX, Netduino RX to phone TX, Netduino GND to phone GND).
Chris
Hi Chris,
thank you very much for your reply. No, I'm not using an RS232 shield. Probably this is the problem!!!
I wired the phone and the netduino together as you mentioned: phone rx to netduino tx, phone tx to netduino rx, phone ground to netduino ground.
I will search for an RS232 shield.
Bye!
Stefano.
#4
Posted 08 January 2011 - 01:18 PM
#5
Posted 08 January 2011 - 01:30 PM
#6
Posted 08 January 2011 - 01:34 PM
#7
Posted 08 January 2011 - 01:55 PM
#8
Posted 08 January 2011 - 06:50 PM
#9
Posted 08 January 2011 - 09:38 PM
A quick google around suggests that the communication with the phone could be either 0-3.3V or 0-5V (depending on model) rather that +/-12V RS232 levels. You may find the SE data cable is dropping the +/-12V from the PC down to these levels at the phone end. If you investigate a bit further it might be possible to avoid the need for a RS232 shield. I could well be wrong though.
- Jan Olof likes this
#10
Posted 09 January 2011 - 10:00 AM
#12
Posted 12 January 2011 - 09:38 PM
#14
Posted 03 February 2011 - 10:15 PM
Ok, probably I bought the wrong shift register. I found this in the compatible shield section.
URF!
Ok, now I have the right rs232 shifter, but nothing to do.
When I send something to the serial port, the RX led flash, but I did not receive anything.
So, now I would like to test separately each component. What is the best way to verify that the rs232 shifter is working fine? Is it possible to connect TX to RX on the serial cable to see that I receive what I sent? Any other way to test the rs232 shifter?
Fortunately today the weather is very cold so the window is closed and I cannot throw everything outside!!!
#15
Posted 03 February 2011 - 11:10 PM
#16
Posted 05 February 2011 - 02:21 PM
#17
Posted 22 February 2011 - 08:11 AM
#18
Posted 20 August 2011 - 02:32 AM
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