http://www.8051projects.net/ Learn to make simple microcontroller projects, pic, 8051, avr and arm projects. download 8051 projects, tutorials, libraries, sample codes. join the microcontroller discussion forum and ask doubts regarding electronics. the best source for 8051 over internet. en-gb 2008-12-01T23:55:21-08:00 contact@nospam.com hourly 1 2000-01-01T12:00+00:00 http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 hi friends. I am trying to send sms with 8051(89c51rc2)and siemens C55.But I failed.I dont know why.When I try to send sms,cellphone turns off. My schematic and C code here.where is my mistake.I dont know. Also I can send sms by hyperterminal with data cable.And I simulated it by proteus succesfully.And it is project to pass the class.Plz help me firends. ///////////////////////////////////////////////////////////////////////// that is C code: /////////////////////////////////////////////////////////////////////////// CODE:#include <t89c51Rx2.h> //
unsigned char rcvd[2];
unsigned char j;
unsigned char k;
bit ok=0;
bit ok1=0;

void init() /// u put int() here
{
TMOD=0x20;
TH1=0xFD;
SCON=0x50;
TR1=1;
}

void sendString(unsigned char *a)
{
while(*a!='\0')
{
SBUF=*a;
while(TI==0);
TI=0;
a++;
}
}
void sendChar(unsigned char b)
{
SBUF=b;
while(TI==0);
TI=0;
}
unsigned char rcv()
{
while(RI==0);
RI=0;
return SBUF;
}
void checkOK()
{
for(j=0;j<2;j++)
rcvd[j]=rcv();
if(rcvd[0]=='o'&&rcvd[1]=='k')
ok=1;
else
ok=0;
}
void checkOKe()
{
k=rcv();
if(k=='>')
ok1=1;
else
ok1=0;
}

void main()
{
P2_0=0;
P2_1=0;
while(1)
{
if(P1_0==0)
{
init();
sendString("AT");
sendChar(0x0D);
checkOK();
if(ok==1)
{
P2_0=1;
sendString("AT+CMGS=19");
sendChar(0x0D);
checkOKe();
if(ok1==1)
{
P2_1=1;
sendString("079109459208003311000C910945664173350000AA05E8329BFD06");
//sms center no:+905429800033, destination number:+905466143753, message:"HELLO"
sendChar(0x1A);
}
else P2_1=0;
}
else
P2_0=0;
}
}
} enson.rar http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 shyam sendString("079109459208003311000C910945664173350000AA05E8329BFD06");//sms center no:+905429800033, destination number:+905466143753, message:"HELLO" what is this??PDU??doesnot the modem support text mesaging??? http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 cllunlu yes it is pdu mode.Because my cellphone is siemens C55 and it supports only pdu mode.I can send sms by hyperterminal with pdu mode.And I simulated it by proteus.Serial communication looks success.But it doesnt work when I do that schematic.Cellphone close itself.I dont know why? http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 cllunlu my cellphone is siemens c55 and pin configuration is:http://pinouts.ru/CellularPhones-P-W/siemens_c55_pinout.shtmlwhere is DTR? http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 Ajay problem seems here..CODE:void checkOK()
{
for(j=0;j<2;j++)
rcvd[j]=rcv();
if(rcvd[0]=='o'&&rcvd[1]=='k')
ok=1;
else
ok=0;
}you are checking for small 'o' and small 'k' whereas phone sends capital 'O' and capital 'K'. so you variable ok is never 1. I hope you got my point.So make the change in program as..CODE:if(rcvd[0]=='O'&&rcvd[1]=='K')
  http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 abbas1707 also you dont need to send all those commands...just try to send at+cmgs.and dont check OK. http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 cllunlu I know.But I wanna check my pdu mode.So I have to know right communication.And my schematic is right? http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 abbas1707 in schematic......try with DTR pin of mobile = high http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 cllunlu But I dont understand DTR pin of mobile=highhow it will be.It necessary.And how? http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 cllunlu this schematic is right too? http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 abbas1707 do you know pin configuration of your mobile connector??you are not using datacable right? http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 cllunlu I am not using data cable.And ı know siemens c55 pin configuration. http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 Ajay as you said u are connecting it to c55 directly then there is no need of DTR.. just direct connection with tx, rx and gnd.Did you try what i said? did you make changes in program? http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 cllunlu ok.I changed my program.You said me change 'O' and 'K' replaca 'o' and 'k'.I did but I havent tried yet.I will try soon.Thnks for everything http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 GioppY I do not see any pull up resistor in your schematic.The 8051 port pin can sink 1.6mA (3.2mA for port 0) and source 60uA.When used as outputs, all port pins will drive the state to which the associated SFR latch bit has been set.When a 0 is written to a bit in port the pin is pulled low (0).When a 1 is written to a bit in port the pin goes into a high impedance state.Only the internal (weak or medium) pull the pin up. http://www.freewebs.com/maheshwankhede/ports.htmlAtmel at89c51rc2 doc4180.pdfPag.13 Port typePag.107 Electrical characteristicsRegards http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 GioppY You have to buffer, or add a pull up resistor to P3.1.Also led design is wrong. 8051 family has open drain output stage with a weak pull up. The cellphone rx pin never see a high level.Regards http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 cllunlu hi gioppy.I didnt understand you.You said "add a pull up resistor to P3.1"I have done already it.After that "led desing is wrong"how?8051 family has open drain output stage with a weak pull up. The cellphone rx pin never see a high level.can you explain them more? http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 Ajay did you test what i said? http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 cllunlu thnks gioppy.Can you make a right schematic for my project .Please... http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 sashijoseph In your schematic just add a 10k resistor between Vcc and P3.1......that's your pullup.Like Gioppy suggested your LED's are sourcing current from the 8051 which is bad...they should be made to sink current into the 8051.Look at the attached ckt..And have you tried out Ajay's suggestion?Please confirm.. http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 cllunlu ajay I have tried your suggestion.But I am failed.Cell phone doesnt give me anything.Where is my mistake plsease help me http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 Ajay I gave you two suggestions which one you tried?replacing ok with OK?try abbas's suggestion too.. no need to wait for OK.. just try sending AT commands. http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 abbas1707 problem can be in micro-mobile connection.can't say more about it http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 cllunlu my schematic and my codes are correct? http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 abbas1707 try to send only 1 command..like atd , tell about response you get http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 sashijoseph Have you tried with the external pullup? http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 Ajay edit your main for a while and replace it with thisCODE:void main()
{
        P2_0=0;
        P2_1=0;
        while(1) {
                if(P1_0==0) {
                        init();
                        sendString("AT");
                        sendChar(0x0D);
                        sendString("ATE0");
                        sendChar(0x0D);
                        P2_0=1;
                        sendString("AT+CMGS=19");
                        sendChar(0x0D);
                        P2_1=1;
                        sendString("079109459208003311000C910945664173350000AA05E8329BFD06");
                        //sms center no:+905429800033, destination number:+905466143753, message:"HELLO"
                        sendChar(0x1A);
                        sendChar(0x0D);
                }
        }
}
 comment the function which you are not using...like checkOK and all.. then try on controller again.waiting for response. http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 cllunlu ajay I havent anytime to do it.Have you any projects that is finished about it.please help me.I have many class too.I havent more timesplease help me. http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 cllunlu just I will change my main function?and but in main functiom havent delay when transmitting at commands http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 cllunlu I didnt understand external puul-up.I know just need when we use P0 port.we have to use external pull up.for P2 port doesnt need external pull up ,doesnt it? http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 Ajay yeah put delay after each at command. http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 abbas1707 you can put delay after this command CODE:
     sendString("AT+CMGS=19");
     sendChar(0x0D);
     msdelay(200);
  http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 cllunlu ok thnks friends.I have sent sms by 8051.I did it.My mistake is connection from 8051 to GSM.Thnks a lot.... http://www.8051projects.net/forum-t8860.html 2008-12-01T23:55:21-08:00 Ajay good glad it worked...