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hi all
please help me . I want to connect 8051 uc to PC so that it can continuously transfer data received on it's port to the PC.
And How can i send data from uc to GSM network using mobile phone.
There are literally thousands of examples of how to do this on the web including several on the Keil site. If you search using Google you'll find many of these fine examples.
Jon
i am using AT89s52 uc and want to connect it to a GSM cell phone(modem of cell phone) and send data serially ,so that data can be send on another cell. where data can has to send to a pc .
what r the ways to connect gsm cell to controller except RS232 or is it the only way.
plese help.
USB is most probably the preferable way to talk with a GSM phone/module, but unless you have a processor with USB, then a normal asynchronous serial interface is the most common.
DIY projects normally use a GSM phone, but that requires that you check if the serial connection on the phone is using RS232 signal levels, or if it is using TTL signals (3.3V, 5V or possibly something else). If using the standard cable for connecting the phone to a computer, then you know the other end of the cable will be using RS232 signal levels.
Commercial projects normally use GSM modules instead, i.e. basically a small circuit board with a high-density connector and a tiny coaxial connector (or solder hole) for fitting the cable of an antenna.
These modules normally interfaces using TTL levels. Many modules are making use of non-standard voltages (at least for the supply voltage) so it is imperative to read the datasheet.
In my experience, GSM modules do *not* use standard TTL levels!
Certainly not 5V, and usually not even 3.3V or 3V.
Levels like 2.7V or 1.8V are not uncommon.
"it is imperative to read the datasheet."
Asolutely!
"want to connect it to a GSM cell phone"
The trouble with using a Phone is that you will almost certainly not have any documentation at all about doing this; neither will you (easily) be able to obtain it from the phone manufacturer.
Therefore, if you want to use a Phone you are going to have to do some serious work with your favourite internet search engine - there is plenty of stuff out there, but it will be up to you to find it!
Your Googling skills aren't looking too hot so far - are you sure you're up to it?
See: www.8052.com/.../read.phtml
You are correct. It was a bad expression for saying that the modules uses "naked logic levels", without any buffering.
It is quite common that logic level converters are needed between module and processor.