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hello
i have a doubt about one of the sample projects you have put up on your website. am talking about the one titled “interfacing a gsm module with 8051 without using pc”.
the code which u have given as sample, wat does it do exactly??? does it display an ‘AT’ that is sent to the gsm module?? does it also show the reply that the gsm module gives??? like “OK”!
this is the link….
i built the circuit as given in the circuit diagram and used the same given code….but am not getting any output on the led… its blank
hey goutam,
led or LCD any ways, are you getting some boxes on LCD or its completly blank.
if you getting boxes then check you connection again. and if its completely blank check the supply for LCD
hello
i passed that hurdle….am getting the response now…i modified the code to suit my needs now…. instead of sending AT i modified it to send, ATD phoneno the code is as follows….
//
#include<regx51.h>
#define port P1
#define dataport P2 // Data port for LCD
sbit rs = port^2;
sbit rw = port^3;
sbit en = port^4;
int count,i;
unsigned char check,str[15];
bit check_space;void init_serial() // Initialize serial port
{
TMOD=0x20; // Mode2
TH1=0xfd; // 9600 baud
SCON=0x50; // Serial mode=1 ,8-Bit data,1 Stop bit ,1 Start bit, Receiving on
TR1=1; // Start timer
}
void delay(unsigned int msec) // Function for delay
{
int i,j;
for(i=0;i<msec;i++)
for(j=0; j<1275; j++);
}void lcd_cmd(unsigned char item) // Function to send command on LCD
{
dataport = item;
rs= 0;
rw=0;
en=1;
delay(1);
en=0;
return;
}void lcd_data(unsigned char item) // Function to display character on LCD
{
dataport = item;
rs= 1;
rw=0;
en=1;
delay(1);
en=0;
return;
}
void lcd_data_string(unsigned char *str) // Function to display string on LCD
{
int i=0;
while(str!=’ ’)
{
lcd_data(str);
i++;
delay(10);
}
return;
}
void lcd()
{
lcd_cmd(0x38); // For using 8-bit 2 row LCD
delay(5);
lcd_cmd(0x0F); // For display on cursor blinking
delay(5);
lcd_cmd(0x80); // Set the cursor on first position of LCD
delay(5);
}void transmit_data(unsigned char str) // Function to transmit data through serial port
{
SBUF=str; //Store data in SBUF
while(TI==0); //Wait till data transmits
TI=0;
}void receive_data() interrupt 4 // Function to recieve data serialy from RS232 into microcontroller
{
RI=0;
str[++count]=SBUF; //Read SBUF
}
unsigned char byte_check() // Function to check carraige return and new line character
{
switch(str[0])
{
case 0x0a:
{ // Return 0x00 for new line
return 0x00;
break ;
}
case 0x0d:
{ // Return 0x01 for carriage return
return 0x01;
break ;
}
default :return 0x02 ; // Return 0x02 for characters except new line and carriage return
}
}void main()
{
lcd(); // Initialize LCD
init_serial(); // Initialize serial port
count=(-1);
delay(500);
lcd_data_string(“Ready”);
delay(10);
lcd_cmd(0x01);
IE=0x94;
transmit_data(‘A’); // Transmit ‘A’ to serial port
delay(1);
transmit_data(‘T’); // Transmit ‘T’ to serial port
delay(1);
transmit_data(‘D’); // Transmit ‘A’ to serial port
delay(1);
transmit_data(‘ ‘); // Transmit ‘A’ to serial port
delay(1);
transmit_data(‘9’); // Transmit ‘A’ to serial port
delay(1);
transmit_data(‘5’); // Transmit ‘A’ to serial port
delay(1);
transmit_data(‘3’); // Transmit ‘A’ to serial port
delay(1);
transmit_data(‘8’); // Transmit ‘A’ to serial port
delay(1);
transmit_data(‘0’); // Transmit ‘A’ to serial port
delay(1);
transmit_data(‘9’); // Transmit ‘A’ to serial port
delay(1);
transmit_data(‘8’); // Transmit ‘A’ to serial port
delay(1);
transmit_data(‘2’); // Transmit ‘A’ to serial port
delay(1);
transmit_data(‘4’); // Transmit ‘A’ to serial port
delay(1);
transmit_data(‘9’); // Transmit ‘A’ to serial port
delay(1);
transmit_data(‘;’); // Transmit ‘A’ to serial port
delay(1);
transmit_data(0x0d); // Transmit carriage return to serial port
delay(50);
while(1)
{
if(count>=0)
{
check=byte_check(); // Check the character
if(check!=0x00)
{
if(check==0x01)
{
if(check_space==1) // Check previous character
{
lcd_data(0x20);
check_space=0;
}
}
else
{
lcd_data(str[0]);
check_space=1;
}
}
count–;
for(i=0;i<count;i++) // Shift the whole array to one left
{
str=str[i+1];
}
}
}
}but the problem is the lcd keeps displaying ready over and over again. sometimes it displays ATD, but doesnt make the call….
help plz…what am i doing wrong??? some problem with the code??
i think im a ltl late at replyiing… u probably might hv figured this out…
u r giving a space character after ATD… delete that and u will be done…
HAI everyone,
i am a beginner of 8051 based systems design, now i am trying to interface gsm modem with 8051 microcontroller,actually my problem is i received the replay from the modem but the it is displayed in LCD at different format[unknown character] some of the characters are in right format[if suppose RING willbe received means it will displayed #$I# #$I#] how can i decode it pls help me….
hey all, are u sure to check the baud rate of your computer while starting the hyperterminal, it asks for baud rate and com port… i suggesat you to get it checked…
hey all, are u sure to check the baud rate of your computer while starting the hyperterminal, it asks for baud rate and com port… i suggesat you to get it checked…
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