Help me about communicating PIC with cellular phone...

[d_hamen]

Yes I read them. I know; FBus works with 115200 bps but I read the thread of "hserin, hserout problems" and I saw that they are all using FBus with 9600 bps. (If I did not misunderstand them )

You said "you are still using PortC which needs 4V for a logic high so the 3.3V from the Nokia will not be detected"

I used a resistor between them. And the voltage across the phone's Rx is nearly 3.5Volt. İs it again a problem if yes;

what must I do then? choose a different port?


Thaks so much...

[dhouston]

You said "you are still using PortC which needs 4V for a logic high so the 3.3V from the Nokia will not be detected"

I used a resistor between them. And the voltage across the phone's Rx is nearly 3.5Volt. İs it again a problem if yes; what must I do then? choose a different port?

Yes. Look at DO40 & DO41 (Vih) Input High Voltage in the Electrical Characteristics section of the datasheet for your PIC. Ports with a Schmidt Trigger buffer (e.g. PortC) need 0.8*Vdd (4V with Vdd=5V) while ports with a TTL buffer (e.g. PortB, some PortA pins) only need 2.0V. See the I/O Ports section for buffer types.

Note that while you can omit the MAX232 (which, in addition to converting voltage levels, inverts the logic) you still need to invert the logic.

Unless the Nokia has auto-baud detection, you either need 115200 or need to send some (?) command to set the baud rate in the Nokia.

[d_hamen]

Hi d_houston;

I have lots of exams for a week.So; Because of my lectures I had to study and couldn't connect to the internet.

Yesterday I bought ericsson A1018s and used it in my project. Also I changed some of my hardware too. (I changed pic and crystal)

And result is perfect! It is working now. I used HSERIN and HSEROUT commands according to serout2, serin2 and I did not inverted. I don't use max232. I directly connect phone's pins to the pic. Now I am trying to make a control system with sms. For example when you send sms "led1" to pic's ericsson phone then first led will light in the circuit.

Thanks for your help d_houston...

Good works