NEED HELP with STRUCT!!!!!

[colin]

Hi all,

If you've experienced creating a struct, pls help and give suggestion!

I created a struct to hold about 30 bytes of data, and declared a pointer pointing to the struct. Pointer would pass around the program thru function to read and write value to the data in the specific object.

My code have a weird problem:
In a while(true) loop, I write and read 30 bytes of data to the object. However, the read, write operation didn't execute and the program counter keep pointing back to the very first function in main() which I have init fuction.

The weird problem is, if I just write says 10 bytes of data to the object, the result was fine(datas were able to print and accurate).
Once I write says 11 bytes of data, the 11 th byte data mess up(11th data( count=0x10, sb->k=count)), as I could see in the register file window, the data was overwritten by some data after the write operation.
If I run the program with write and read 30 bytes of data, the program counter keep pointing back to the very first function in main which is out side the while(true) loop.

If you'v experienced creating a struct and declare a pointer pointing to the object, could you pls provide the code which I could test and see if my code contains problem or the compile contains problem.

You help would be greatly appreciated!!

Pic16f877, mplab 6.3, pcw 3.176, icd2, picdem 2 plus

what i'm tring to do is:
int coutn=0;
while(1)
{
data->a=count;
data->b=count;
.......

printf("%x", data->a);
printf("%x", data->b);
.........
count++;
}

[Neutone]

Try to do this with arrays. The code created from structures is less predictable for me. Maybe I just don't understand structures well enough.

int8 DataA[30];
int8 DataB[30];

while(1)
{ x++;
DataA[x]=x;
DataB[x]=x-30;
if(x>29) x=0;
printf("%x", DataA[x]);
printf("%x", DataB[x]);
}

[PCM programmer]

The following program works OK. The structure has 14 elements,
and it was compiled with PCM vs. 3.176. It does, however, use
the "." method of accessing structure elements.

#include "c:\Program Files\Picc\Devices\16F877.H"
#fuses HS, NOWDT, NOPROTECT, BROWNOUT, PUT, NOLVP
#use delay(clock = 8000000)
#use rs232(baud = 9600, xmit=PIN_C6, rcv = PIN_C7, ERRORS)

struct
{
char a;
char b;
char c;
char d;
char e;
char f;
char g;
char h;
char i;
char j;
char k;
char l;
char m;
char n;
}my_struct;

//=========================
void main()
{

my_struct.a = 'a';
my_struct.b = 'b';
my_struct.c = 'c';
my_struct.d = 'd';
my_struct.e = 'e';
my_struct.f = 'f';
my_struct.g = 'g';
my_struct.h = 'h';
my_struct.i = 'i';
my_struct.j = 'j';
my_struct.k = 'k';
my_struct.l = 'l';
my_struct.m = 'm';
my_struct.n = 'n';


printf("%c\n\r", my_struct.a);
printf("%c\n\r", my_struct.b);
printf("%c\n\r", my_struct.c);
printf("%c\n\r", my_struct.d);
printf("%c\n\r", my_struct.e);
printf("%c\n\r", my_struct.f);
printf("%c\n\r", my_struct.g);
printf("%c\n\r", my_struct.h);
printf("%c\n\r", my_struct.i);
printf("%c\n\r", my_struct.j);
printf("%c\n\r", my_struct.k);
printf("%c\n\r", my_struct.l);
printf("%c\n\r", my_struct.m);
printf("%c\n\r", my_struct.n);


while(1);
}

[john cutler]

This worked for me....

typedef struct {
byte addr_to; //destination address
byte addr_from; //origination address
byte serv_req; //service request flag
byte enc_data[8]; //encoder data array
int check; // crc
} packet, *packetPtr;

packet mypack, *mp;

..........
...........
main () {

mp = &mypack;

mp->addr_to = 0x12;
mp->enc_data{0} = 0x88;

printf( "addr_to = %u\n",mp->addr_to);
printf( "enc_data[0] = %u\n", mp->enc_data[0]);

etc etc

[Mark]

I suggest that you post the actual program and the struct. Your example does not contain a data++. Without this, the pointer will never increment. Maybe you have it in your actual code but it is hard to help without a true representation of the code.