Help me about communicating PIC with cellular phone...

[d_hamen]

Hi, i have to communicate PIC 16F877 with my Nokia 7250i mobile phone. I want to make a call by using PIC. But there's a problem i couldn't solve. I sent the link of the schematic of circuit, and wrote my codes below. Waiting for your help...

INCLUDE "modedefs.bas"

' ******* Definitions *******
' ------------------------------

DEFINE OSC 10 ' Define clock Oscillator Frequency at 10Mhz
DEFINE HSER_RCSTA 90H ' Enable Hardware USART receive
DEFINE HSER_TXSTA 24H ' Set Hardware USART parameters
DEFINE HSER_BAUD 9600 ' Set baud rate to 9600
define HSER_CLROERR 1


OUTPUT PORTC.6
INPUT PORTC.7

PORTC = %00000000 ' Initial state of PORT C

Start:
PAUSE 1000
HSerout ["atD05354511850",str]

goto start

end

 

[budhy]

The ATD command sets a voice, data or fax call.

ATD<str>;
Dial the dialing string <str> with the voice utility
Valid dial modifiers: ”T” (tone dialing), ”P” (pulse dialing) is ignored.
The character ”;” is important, for this tells the phone that the call
should be set up with the voice utility. Otherwise an attempt is made to
set up a data call, which the phone immediately acknowledges with
”ERROR”.
The dial command responds with OK to the user right after starting a
voide call.

 

[d_hamen]

So what must be the codes now? would you write down the correct codes.

 

[budhy]

I know nothing about PIC, sent this command atD05354511850; with your language

The character ”;” is important, for this tells the phone that the call
should be set up with the voice utility.

 

[basemgergawy]

i think you have two errors in your code

first you forget the semicolon ;

second you made infinit loop which sends the command infinit times. you should send the command once and make the infinit loop after the command as....


....
....

HSerout ["atD05354511850;",str]

Start:
goto start
.....
....
....

 

[d_hamen]

Hi again;
I tried the AT Commands with " ; ".
But still it is not working. May there be any problem with my hardware.

 

[budhy]

Use Windows HyperTerminal to talk to your Nokia 7250i, after every thing OK continue with your PIC 16F877.

 

[sento]

Check if communiaction speed is OK.
I connected SiemensC45 with PIC16F84
and comm.speed must be !!! : 19200 1-8-N-1
19200bps
1 start bit
8 data bits
none parity
1 stop bit

... it works (with SieC45);

Before i tried communicate PC --- SiemensC45
to get know speed, ... etc

bye

 

[budhy]

But still it is not working. May there be any problem with my hardware.

Cell phone is Low Voltage device, it is operate on 3.3 V.
PIC16F877 has Wide operating voltage range: 2.0V to 5.5V

on above circut you have to run PIC16F877 on 3.3 Volt, not 5 Volt