Extract the data from array_buffer and stored in the variable - c

Question

I am receiving data continuously using UART and stored in the buffer in the following form::
$GNRMC,114811.00,A,3558.94849,N,14008.90158,E,0.076,,141115,,,A*69
$GNVTG,,T,,M,0.076,N,0.141,K,A*38
$GNGSA,A,3,,,,,,,,,,,,,3.03,1.18,2.80*1E
$GPGSV,3,2,09,20,04,163,,22,49,280,29,24,45,048,33,25,53,183,28*75
$GNGLL,3558.94849,N,14008.90158,E,114811.00,A,A*70*
I want to extract only the $GNRMCdata and store it on some variable year, mon, day, hour, min, sec so that I can display that in 16*2LCD. The value right after $GNRMC 114811 is the time. But I am not getting the data on those variables. Where I am wrong?
void gps_getinfo(unsigned char rx2_id_buff[]);
void uart2_rx_int(void);
#define MAX_LINEBUF 70
char gps_linebuf[MAX_LINEBUF];
unsigned char time_flag;
unsigned char rx2_id_buff[70];
unsigned char rx2_id_pointer;
unsigned char year[4]={0},mon[4]={0},day[4]={0};
unsigned char hour[4]={0},min[4]={0},sec[4]={0};
#pragma interrupt uart2_rx_int (vect=0x16)
void uart2_rx_int(void)
{
unsigned char error;
error = SSR11 & 0x07;
rx2_id = SDR11;
if (error == 0) {
if(rx2_id == '$' ) rx2_id_pointer = 0;
rx2_id_buff[rx2_id_pointer] = rx2_id; //storing data in the buffer received form UART
gps_getinfo(rx2_id_buff[rx2_id_pointer]);
}
else
rx2_id_buff[rx2_id_pointer] = err | 0xF0;
rx2_id_pointer++;
if (rx2_id_pointer > 69) rx2_id_pointer = 0;
}
void gps_getinfo(unsigned char rx2_id_buff[]) {
short i,j,len;
char *ptr,*ptrTop;
unsigned char j1,j2;
unsigned char comma[20]={0};
if (rx2_id_buff != '\n') {
gps_linebuf[idx++] = rx2_id_buff;
if(idx >= MAX_LINEBUF)idx=0;
}
else {
gps_linebuf[idx++] = '\n';
gps_linebuf[idx] = '\0';
i = MAX_LINEBUF;
j = idx - 1;
while(1) {
if(gps_linebuf[j] == '$') break;
j--;
if(j < 0) j = MAX_LINEBUF - 1;
if(i-- == 0) {
gps_linebuf[0] = 0; idx=0;
return;
}
}
gps_linebuf[idx] = 0; idx=0;
ptrTop = (char *)&gps_linebuf[j];
ptr = (char *)&gps_linebuf[j];
//$GNRMC,114811.00,A,3558.94849,N,14008.90158,E,0.076,,141115,,,A*69
if(strstr(ptrTop,"GNRMC")!=0) {
len=strlen(ptr);
j=0;
for(i=0; i<len; ++i,ptr++) {
if(*ptr == ',') {
comma[j++] = i+1;
}
}
ptr = ptrTop;
j1=comma[0];
j2=comma[1] - comma[0];
time_flag = 0;
if(j2>=4) {
strncpy((char *)hour,ptr+j1 ,2);
strncpy((char *)min, ptr+j1+2,2);
strncpy((char *)sec, ptr+j1+4,2);
time_flag |=0x01;
}
j1=comma[1];
j2=comma[2] - comma[1];
if(j2>=1) {
if(*(ptr + j1) == 'A') {
time_flag |=0x04;
}
}
j1=comma[8];
j2=comma[9] - comma[8];
if(j2>=4) {
strncpy((char *)day, ptr+j1 ,2);
strncpy((char *)mon, ptr+j1+2,2);
strncpy((char *)year, ptr+j1+4,2);
time_flag |=0x02;
year = atoi((char *)year);
mon = atoi((char *)mon);
day = atoi((char *)day);
hour = atoi((char *)hour);
min = atoi((char *)min);
sec = atoi((char *)sec);
}
}
}
}

Answer 1

There are a few errors in your code. I have tested it, and with some smaller changes it works as expected.
Add the correct header files:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
Please change
if (rx2_id_buff != '\n') {
gps_linebuf[idx++] = rx2_id_buff;
to
if (rx2_id_buff[0] != '\n') {
gps_linebuf[idx++] = rx2_id_buff[0];
The integer output variables need to have different names than the corresponding string variables:
int i_year,i_mon,i_day;
int i_hour,i_min,i_sec;
i_year = atoi((char *)year);
i_mon = atoi((char *)mon);
i_day = atoi((char *)day);
i_hour = atoi((char *)hour);
i_min = atoi((char *)min);
i_sec = atoi((char *)sec);