Cannot Receive 4digit Integer value from serial port

[Bakhtiar]

Dear Concern,

 

I have send 1 digit value from serial port and it received and work but when i am sending 4 digit integer value at a time from serial port it cannot reveive the value it receive only 1 digit value. Can any one help me.

Thanks in advanced.

 

Bakhtiar

[Ashutosh Bhatt]

from serial port each and every letter or digit is received as ASCII value that is also saparately

that means if you want to send 4 digit value as 3425 then serial port will send 4 ASCII values

33h, 34h, 32h and 35h

you have to store all four values in an array (or table)

then you have to write a program to convert all 4 ASCII values into digits and finally combine them into single value

[Bakhtiar]

Thanks a lot about your reply.

 

 

Ok if i use array then my program is receive using serial first time data here is my code.

 

void compare()
{

if(strcmp(msg,”1234″)==0)
{
 
     lcdcmd(0x01);
     lcddata(‘B’);
    
   }
if (strcmp(msg,”4321″)==0)
{

 
     lcdcmd(0x01);
     lcddata(‘C’);
        

   }
}

 

 

void recieve() interrupt 4
{

int i;
while (RI != 1) {;}

msg[i++] = SBUF;
RI = 0;    

        compare();
    
 
 }

 

 

for example: after running the code it take any one of the input

 

if input “1234”

 

then it worked.

 

but at the same time when i input

 

“4321”

 

it will not take.

 

please help me

 

[Ashutosh Bhatt]

you have not initialized i as i=0

also after getting all four codes you have to again reset i to 0

[Bakhtiar]

Thanks a lot sir,

 

Your instruction is finally give me solution.I have appled and its done successfull.

 

I reset the “i”  and it worked.

 

 

Thanks again Sir.

 

 

 

[Ashutosh Bhatt]

good

now post your working code your project details

so that other can get ideas

[Bakhtiar]

It work fine but lettle problem i faceing, this is

the define string compare is ok for string compare but if i again press the same keys the
it will take only first digit for example

#include<reg51.h>
#include<string.h>
#define dataport P2
int  i=0;
unsigned char msg[20];
void lcdcmd(unsigned char);
void lcddata(unsigned char);

void compare()
{

if(strcmp(msg,”1234″)==0)
{
     
     lcdcmd(0x01);
     lcddata(‘B’);
    
     i=0;
    
   }
 if (strcmp(msg,”4321″)==0)
{

 
     lcdcmd(0x01);
     lcddata(‘C’);
    
     i=0;
        }
}

void recieve() interrupt 4
{

while (RI != 1) {;}

msg[i++] = SBUF;
    RI = 0;

        compare();
    
         
 }

void main()
{
while(1);
}
void lcdcmd(unsigned char value)
{   dataport=value;
      rs=0;
      rw=0;
      en=0;
      delay(1);
      en=1;
}

void lcddata(unsigned char value2)
{  dataport=value2;
      rs=1;
      rw=0;
      en=0;
      delay(1);
      en=1;
}

if again press “1” then the first compare block will display ‘B’ it will
not take “234”
but if i press another digit block that is “4321” it will take that one and display ‘C’
 again if i press first 4 digit then
it will display ‘B’

it will still not empty the fist digit block
but take second digit block again it will take first digit block so on.

[Ashutosh Bhatt]

in your compare() function

after first condition if(….)

next condition must be else if (….)

not just if

[Bakhtiar]

still it will take the first block value ,i mean the array value is not empty.

 

if i press another block of value then previous array value will empty.

 

for example

 

first time

 

when press “1234” then lcd display

 

if i again press only “1” of that block that time also lcd display.But i want if i again press “1234” second time then lcd will display.

 

 

after your advice i change my code in below way.

 

void compare()
{

if(strcmp(msg,”1234″)==0)
{
     
     lcdcmd(0x01);
     lcddata(‘B’);
    
     i=0;
    
   }
else if (strcmp(msg,”4321″)==0)
{

 
     lcdcmd(0x01);
     lcddata(‘C’);
    
     i=0;
        }
}

void recieve() interrupt 4
{

while (RI != 1) {;}

msg[i++] = SBUF;
    RI = 0;

        compare();
    
         
 }

 

but still face problem

[Ashutosh Bhatt]

your compare function should be only called after you receive all digits like 4 or 5 etc, 

you are calling compare function everytime when you receive any byte

[Bakhtiar]

Thanks your valuable answer.

 

Please ,

Can you tell how can i do this or any example. Then it will be very helpfull for me.

 

 

Thanks

 

 

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