Hi, I am not big champ. of C.Next thing I am trying to do using these value 0xFE and 0x02 to control the I/O of board using MYSQL C based API at baord side.And using PHP admin to insert the value in MYSQL Database.And hotter_alert | varchar(40) | YES | | NULL | | hotter_alert is the field name and want to control the I/O of board from server side by inserting value.From BOARD side I am able tho fetch hooter_alert field value as row[0] and *PCDR is pointer to which want to assign row[0] value.Problem I am getting is that I am able to fetch the value from Database but Not able to assign properly this value *PCDR register.What I thought Problem is that row[0] value fetching from DATABASE come in string of character as such it's printing right value only when %s is given.And *PCDR is declared as unsigned int.Please suggest me How can I assign row[0] value to *PCDR register,so that I can control I/O from server side. Code: #include <stdio.h> #include <stdlib.h> #include "mysql.h" #include<unistd.h> #include<sys/types.h> #include<sys/mman.h> #include<stdio.h> #include<fcntl.h> #include<string.h> void exiterr(int exitcode) { fprintf( stderr, "%s\n", mysql_error(conn) ); exit( exitcode ); } int main(int argc, char **argv) { MYSQL *conn; MYSQL_RES *res; MYSQL_ROW row; uint i = 0; char *server = "10.64.21.63"; char *user = "root"; char *password = "PASSWORD"; /* set me first */ char *database = "mysql"; unsigned char *start; volatile unsigned int *PCDR, *PCDDR; int fd = open("/dev/mem", O_RDWR); start = mmap(0, getpagesize(), PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0x80840000); PCDR = (unsigned int *)(start + 0x08); // port c data register PCDDR = (unsigned int *)(start + 0x18); // port c direction register (!mysql_real_connect(conn, server, user, password, database, 0, NULL, 0)) exiterr(1); if (mysql_select_db(conn,"location")) exiterr(2); if (mysql_query(conn,"SELECT hotter_alert from location")) exiterr(3); if (!(res = mysql_store_result(&mysql))) exiterr(4); while((row = mysql_fetch_row(res))) { for (i=0 ; i < mysql_num_fields(res); i++) char * val=row[0] *PCDDR = 0x01; // Make bit 0 an output Port C bit 0 is connected to the FET *PCDR = val; // Turn the FET on printf("%s\n",row[0]); } if (!mysql_eof(res)) exiterr(5); mysql_free_result(res); mysql_close(&mysql); close(fd); return 0; }