I can send/receive data to my cell by the pic using usb?

pattousai · Joined: 23 Aug 2006 Posts: 37

Hi everybody...

I'm trying to send AT commands to a regular cellphone, the problem is that the today's cells only have the usb port...

Is there a way to comunicate with them using the usb for the pic?

I'm totally new in this area (i already have done some stuff with pics, but i guess that was basic stuffs) and from what i read, the usb comunication is realy complicated, needing drivers and etc...

So... if there is a way to do that, what steps i have to take?

Thanks very much for the attention and sorry for the bad english (i'm also very tired :/)

Ttelmah · Guest

Simple answer. No......
The problem is that the USB port on the phone, is a 'slave' port. The USB port on the PIC is also a 'slave'. All USB transactions, require a 'master' at one end.
However (there always have to be these caveats), _a few_ phone ports are 'smart, and can operate as a USB slave, or switch to being a 'normal' serial port, when a special cable is attached. Look for these.
The only other answer is to implement a USB 'master' device. The commonest chip for people wanting a relatively easy solution, is the FTDI Vinculum', and there is demo code for this, to implement a USB master to talk to some 'standard' devices (a USB 'CDC' device - 'com port' is one of them), and this _might_ be able to talk to such a phone. This depends on how the USB interface on the phone is implemented - some use much more complex connections for things like their camera functions...
It is not 'easy'.

Best Wishes

pattousai · Joined: 23 Aug 2006 Posts: 37

Ttelmah · Guest

You have to look, and see if they offer a RS232 cable. Some of the more expensive Nokia models do, using the same connection as the USB. What the phone does, is look at the signals presented on the connector, and changes 'mode' according to what is there. Some Samsung models also still offer RS232, with a larger connector, as does at least one Ericsson model. You will need to be using a hardware RS232 port on the PIC, and interrupt driven serial with a significant buffer, since most modern phones send quite large packets, with quite high baud rates.
Alternatively (and simpler really), just pick up one of the industrial cellphone modem 'modules'. These usually cost more than most mass production phones, but have an RS232 interface designed to talk directly to a microcontroller. A typical unit is the GM862.

Best Wishes