rs232.c

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#include "h1.h"

/* some prototypes*/
void signal_1( int);
void rs232_clear_exit( int);

/* global variables */
int shm_id1, shm_id2;
unsigned char *SHM_config, *SHM_data;
char RS232_DEVICE[20] = "/dev/ttyUSB0";

int rs232(void)
{
        
        printf("rs232 started!\n");

        /* signals */
        signal(SIGUSR1,signal_1);
        signal(SIGINT, rs232_clear_exit);
        signal(SIGTERM, rs232_clear_exit);

        /* set shared memory to zeros */
        memset(&SHM_data, 0, SHM_SIZE );
        memset(&SHM_config, 0, SHM_SIZE );

        /* more variables */
        int running, rs_connect, first_time, continuos, send1value, new_order;
        char reading_mode[128];
        int p=getppid();        //parent pid
        int n, i, fd;
        unsigned char buf;      //data receaved from serial port
        int n_sensors;  //total number of sensors
        int n_ultrasounds, n_infrared;  //number of ultrasounds and infrared sensors
        int units;      //units


        strcpy(reading_mode,"null");
        rs_connect=0;
        running=0;
        new_order=0;

        /*_GET SHARED MEMORY 1*/
        shm_id1 = GetSharedMem("gtk.c");
        if(shm_id1 == -1)       return -1;      //failure

        SHM_config = shmat(shm_id1, (void *) 0, 0);
        if(SHM_config == (unsigned char *) (-1)) {perror("shmat");exit(1);}
        /********************/

        /*_GET SHARED MEMORY 2*/
        shm_id2 = GetSharedMem("rs232.c");
        if(shm_id2 == -1)       return -1;      //failure

        SHM_data = shmat(shm_id2, (void *) 0, 0);
        if(SHM_data == (unsigned char *) (-1)) {perror("shmat");exit(1);}
        /********************/


        /* Main cicle, runs until the parent it's alive ******************************************/
        do
        {
                
        //signal receaved, what to do?
        if (sig_1>0)    
        {
                if (SHM_config[0] == '1') {rs_connect=1; printf("connect!\n");}
                //else if (SHM_config[0]== '2') {running=0; rs_disconnect=1; printf("disconect!\n");}
                else if (SHM_config[0]== '3') {running=1; strcpy(reading_mode,"continuos"); printf("continuos\n");}
                else if (SHM_config[0]== '4') {running=1; strcpy(reading_mode,"single_reading"); printf("single_reading\n");}
                else if (SHM_config[0]== '5') {running=0; strcpy(reading_mode,"stop"); printf("Stop\n");}
                else if (SHM_config[0]== '6') {running=1; strcpy(reading_mode,"get_reading"); printf("get_reading\n");}
                new_order=1;
                sig_1=0;
        }
        
        /* See if its time to connect */
        if (rs_connect==1)
        {
                /* RS232 Configuration */
                printf("trying to connect using : %s\n", RS232_DEVICE);
                fd=open(RS232_DEVICE, O_RDWR);  // /dev/ttyUSB0
                if(fd==-1)      {printf("Opening error!\n"); sprintf(SHM_config, "x\0"); rs_connect=0; kill(getppid(), SIGUSR2);  continue;}

                struct termios options;
                printf("Setting Parameters...\n");
                tcgetattr(fd, &options);
                cfsetispeed(&options, B9600); /* Set the baud rates to 9600 */
                cfsetospeed(&options, B9600);
                                
                /* Enable the receiver and set local mode */
                options.c_cflag |= (CLOCAL | CREAD);
                options.c_cflag &= ~PARENB; /* Mask the character size to 8 bits, no parity */
                options.c_cflag &= ~CSTOPB;
                options.c_cflag &= ~CSIZE;
                options.c_cflag |= CS8; /* Select 8 data bits */
                options.c_cflag &= ~CRTSCTS; /* Disable hardware flow control */

                /* Enable data to be processed as raw input */
                options.c_lflag &= ~(ICANON | ECHO | ISIG);
                options.c_cc[VMIN]=0;//it will wait for one byte at a time.
                options.c_cc[VTIME]=10;// it will wait for 0.1s at a time.
                /* Set the new options for the port */
                tcsetattr(fd, TCSANOW, &options);
                /********************/

                rs_connect=0;
                printf("Connected!\n");

                /* send z, so the parent will know the serial port was open */
                sprintf(SHM_config, "z\0");     
                kill(getppid(), SIGUSR2);
        }


        /* send orders to pic*/
        if (new_order==1)
        {
                if (strcmp(reading_mode, "continuos")==0) {write(fd, "r", 1); /*printf("enviar r para pic\n");*/}
                else if (strcmp(reading_mode, "single_reading")==0) {write(fd, "1", 1); /*printf("enviar 1 para pic\n");*/}
                else if (strcmp(reading_mode, "get_reading")==0) {write(fd, "1", 1); /*printf("enviar 1 para pic\n");*/}
                else if (strcmp(reading_mode, "stop")==0) {write(fd, "s", 1); /*printf("enviar s para pic\n");*/}
                new_order=0;
        }

        /* Reading from serial port*/
        if (running==1)
        {
                n=read(fd, &buf, 1);

                if (n<0)        { /*printf("Reading error!\n");*/ continue;}
                if (n>0)
                {
                        if (buf==0xff)
                        {
                                //printf("Start byte receaved!\n");
                                read(fd, &buf, 1);      //read the information byte
                                n_ultrasounds=buf & 7; // 7 = 0b00000111
                                n_infrared=(buf>>3) & 7 ; // 7 = 0b00000111
                                units=(buf>>6); //units of the data receaved
                                n_sensors=n_ultrasounds + n_infrared;   //total number of sensors  

                                SHM_data[0]=n_sensors;
                                SHM_data[1]=n_ultrasounds;
                                SHM_data[2]=n_infrared;
                                SHM_data[3]=units;

                                for (i=4; i<(n_sensors+4); i++)
                                {
                                        read(fd, &buf, 1);      //read from serial port one byte for each sensor
                                        if (buf==0xff) continue;        /* value of distance cannot be 0xff */
                                        SHM_data[i] = buf;
                                }

                                /* Shell Debug */
                                //printf("Numero total de sensores: %d\n", n_sensors);
                                //printf("Numero de sensores ultrasons: %d\n", n_ultrasounds);
                                //printf("Numero de sensores infravermelhos: %d\n", n_infrared);
                                //for (i=0; i<n_sensors; i++) {printf("sensor%d:%d\n",(i+1), sensor.value[i]);}

//                              printf("working...\n");
                                kill(getppid(), SIGUSR2);

                                if (strcmp(reading_mode, "single_reading")==0){running=0; /*printf("devia parar!\n");*/}
                                if (strcmp(reading_mode, "get_reading")==0) {running=0; /*printf("devia parar!\n");*/} 
                        }
                        else    
                        {printf("Wainting for start byte!\n");}
                }
        }
        }       while(getppid()==p);

        close (fd);

        /* detach from the mem segment */
        if(shmdt(SHM_config) == -1){perror("shmdt"); exit(1);}
        /*Allow elimination of shared memory */
        if(shm_id1 > 0) shmctl(shm_id1, IPC_RMID, NULL);

        /* detach from the mem segment */
        if(shmdt(SHM_data) == -1){perror("shmdt"); exit(1);}
        /*Allow elimination of shared memory */
        if(shm_id2 > 0) shmctl(shm_id2, IPC_RMID, NULL);
        
        return 0;
}


void signal_1(int x)
{
        /* reveaved a signal in order to chage the usb device */
        if (SHM_config[0]=='7') {strcpy(RS232_DEVICE,"/dev/ttyUSB0"); /*printf("usb0\n");*/ return;}
        else if (SHM_config[0]=='8')    {strcpy(RS232_DEVICE,"/dev/ttyUSB1"); /*printf("usb1\n")*/;return;}
        else if (SHM_config[0]=='9')    {strcpy(RS232_DEVICE,"/dev/ttyUSB2");/*printf("usb2\n");*/return;}
        
        /* receaved a signal for something else, will see what for, in the main cicle */
        else { sig_1++;}
}


void rs232_clear_exit(int xx)
{
        /* detach from the mem segment */
        if(shmdt(SHM_config) == -1){perror("shmdt"); exit(1);}
        /*Allow elimination of shared memory */
        if(shm_id1 > 0) shmctl(shm_id1, IPC_RMID, NULL);

        /* detach from the mem segment */
        if(shmdt(SHM_data) == -1){perror("shmdt"); exit(1);}
        /*Allow elimination of shared memory */
        if(shm_id2 > 0) shmctl(shm_id2, IPC_RMID, NULL);;

        exit(0);
}

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