Serial read/write /dev/tty check

0
votes

I'm trying to connect a PIC24 uC with an Armadillo IoT Gateway, which runs on Linux. I already read the following thread: How to read/write to tty* device?

But as I was told to avoid asking questions there, I opened up a new one :/

According to the device manual, the RS232C connector`s TTY device file is /dev/ttymxc3. If I understood the above thread correctly, when a external device is connected via the corresponding connector, the sent data can be read from the /dev/tty* file? Thus, I as the programmer do not have to take buffers etc. into consideration.

I updated now the main code of the gateway in the following way:

FILE *dental_unit_data; //new
int main(void)
{   
    //existing, non relevant code...

    //new; data acquisition 
    dental_unit_data = fopen("/dev/ttymxc3", "r"); 

    ctl_auto_du(dental_unit_data); //reads the data from the dental_uni_data 
    //file. Then sends the acquired data to the database.

The source code for ctl_auto_du(int *fd) is provided below. Is it really that simple, or did I fundamentally misunderstand something?

int ctl_auto_du(int *fd) 
{

    //int result,err,sig;

    size_t count = 0;
    unsigned char wcmd[SP_WRITE_BUF_SIZE];
    size_t wsize;
    unsigned char rcmd[SP_READ_BUF_SIZE];
    size_t rsize;

    Event_t events[TYPE_COUNT];
    size_t event_count;
    CtlLog_t ctl_log;
    long long int now_ms;

    memset(events,0x0,sizeof(Event_t) * TYPE_COUNT); //events has 34 entries, put 0x0 inn all of those

    //struct timeval tv_now;

    //char *dataArr[50];

    //double tmpd;
    //int seisu;
    //int i;

    DU_t *latest_du;

    //起動時に全ＩＤ


    while (TRUE) {
        system(LED_DU_OFF);

        //int idx = 0;

        memset(&latest_du,0x0,sizeof(latest_du));
        memset(wcmd,0x0,sizeof(wcmd));
        memset(rcmd,0x0,sizeof(rcmd));
        wsize = 0;
        rsize = 0;

        if (g_do_forced_termination == TRUE) {
            fprintf( stderr, "!!!Ctl DU Thread Forced termination !!!\n");
            break;
        }

        //受信
        count = recv_du(fd, rcmd); //rcmd = receive buffer, stores read bytes

        if (count > 0) {
            memset(events,0x0,sizeof(Event_t) * TYPE_COUNT);
            memset(&ctl_log,0x0,sizeof(CtlLog_t));

            event_count = 0;
            wsize = 0;
            now_ms = get_now_milliseconds();

            system(LED_DU_ON);

            rsize = count;

            printf("ctl_du read size[%d]\n", rsize);
            printf("ctl_du_cmd read data\n");

            printf_hex(rcmd, rsize);

            latest_du = (DU_t *)rcmd;

            ctl_log.ins_datetime.ullint = now_ms;
            memcpy(ctl_log.data.bytes,rcmd,10); //「歯科機器 -> ArmadilloIoT」のデータ；

            insert_ctl_log(ctl_log); //int return value; will give unused warning //save ctl_log to DB

            if (latest_du->func_cd.uchar == 0x44) {  //check function code; 0x44==D --> if contains data:
                //D, g_latest_du filled with 0x0 during main call.
                if (g_latest_du.byte0.bf.id00 != latest_du->byte0.bf.id00) { //first bit of first byte; checks if id is set
                    events[event_count].eve_datetime.ullint = now_ms;        // and thus being used.
                    events[event_count].eve_type_num.uchar = 0;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte0.bf.id00;
                    event_count ++;
                }
                if (g_latest_du.byte0.bf.id01 != latest_du->byte0.bf.id01) { 
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 1;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte0.bf.id01;
                    event_count ++;
                }
                if (g_latest_du.byte0.bf.id02 != latest_du->byte0.bf.id02) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 2;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte0.bf.id02;
                    event_count ++;
                }
                if (g_latest_du.byte0.bf.id03 != latest_du->byte0.bf.id03) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 3;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte0.bf.id03;
                    event_count ++;
                }
                if (g_latest_du.byte0.bf.id04 != latest_du->byte0.bf.id04) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 4;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte0.bf.id04;
                    event_count ++;
                }
                if (g_latest_du.byte0.bf.id05 != latest_du->byte0.bf.id05) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 5;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte0.bf.id05;
                    event_count ++;
                }
                if (g_latest_du.byte0.bf.id06 != latest_du->byte0.bf.id06) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 6;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte0.bf.id06;
                    event_count ++;
                }
                if (g_latest_du.byte0.bf.id07 != latest_du->byte0.bf.id07) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 7;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte0.bf.id07;
                    event_count ++;
                }
                if (g_latest_du.byte1.bf.id08 != latest_du->byte1.bf.id08) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 8;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte1.bf.id08;
                    event_count ++;
                }
                if (g_latest_du.byte1.bf.id09 != latest_du->byte1.bf.id09) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 9;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte1.bf.id09;
                    event_count ++;
                }
                if (g_latest_du.byte1.bf.id10 != latest_du->byte1.bf.id10) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 10;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte1.bf.id10;
                    event_count ++;
                }
                if (g_latest_du.byte1.bf.id11 != latest_du->byte1.bf.id11) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 11;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte1.bf.id11;
                    event_count ++;
                }
                if (g_latest_du.byte1.bf.id12 != latest_du->byte1.bf.id12) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 12;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte1.bf.id12;
                    event_count ++;
                }
                if (g_latest_du.byte1.bf.id13 != latest_du->byte1.bf.id13) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 13;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte1.bf.id13;
                    event_count ++;
                }
                if (g_latest_du.byte1.bf.id14 != latest_du->byte1.bf.id14) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 14;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte1.bf.id14;
                    event_count ++;
                }
                if (g_latest_du.byte1.bf.id15 != latest_du->byte1.bf.id15) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 15;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte1.bf.id15;
                    event_count ++;
                }
                if (g_latest_du.byte2.bf.id16 != latest_du->byte2.bf.id16) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 16;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte2.bf.id16;
                    event_count ++;
                }
                if (g_latest_du.byte2.bf.id17 != latest_du->byte2.bf.id17) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 17;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte2.bf.id17;
                    event_count ++;
                }
                if (g_latest_du.byte2.bf.id18 != latest_du->byte2.bf.id18) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 18;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte2.bf.id18;
                    event_count ++;
                }
                if (g_latest_du.byte2.bf.id19 != latest_du->byte2.bf.id19) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 19;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte2.bf.id19;
                    event_count ++;
                }
                if (g_latest_du.byte2.bf.id20 != latest_du->byte2.bf.id20) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 20;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte2.bf.id20;
                    event_count ++;
                }
                if (g_latest_du.byte2.bf.id21 != latest_du->byte2.bf.id21) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 21;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte2.bf.id21;
                    event_count ++;
                }
                if (g_latest_du.byte2.bf.id22 != latest_du->byte2.bf.id22) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 22;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte2.bf.id22;
                    event_count ++;
                }
                if (g_latest_du.byte2.bf.id23 != latest_du->byte2.bf.id23) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 23;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte2.bf.id23;
                    event_count ++;
                }
                if (g_latest_du.byte3.bf.id24 != latest_du->byte3.bf.id24) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 24;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte3.bf.id24;
                    event_count ++;
                }
                if (g_latest_du.byte3.bf.id25 != latest_du->byte3.bf.id25) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 25;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte3.bf.id25;
                    event_count ++;
                }
                if (g_latest_du.byte3.bf.id26 != latest_du->byte3.bf.id26) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 26;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte3.bf.id26;
                    event_count ++;
                }
                if (g_latest_du.byte3.bf.id27 != latest_du->byte3.bf.id27) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 27;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte3.bf.id27;
                    event_count ++;
                }
                if (g_latest_du.byte3.bf.id28 != latest_du->byte3.bf.id28) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 28;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte3.bf.id28;
                    event_count ++;
                }
                if (g_latest_du.byte3.bf.id29 != latest_du->byte3.bf.id29) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 29;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte3.bf.id29;
                    event_count ++;
                }
                if (g_latest_du.byte3.bf.id30 != latest_du->byte3.bf.id30) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 30;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte3.bf.id30;
                    event_count ++;
                }
                if (g_latest_du.byte3.bf.id31 != latest_du->byte3.bf.id31) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 31;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte3.bf.id31;
                    event_count ++;
                }
                if (g_latest_du.byte4.bf.id32 != latest_du->byte4.bf.id32) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 32;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte4.bf.id32;
                    event_count ++;
                }
                if (g_latest_du.byte4.bf.id33 != latest_du->byte4.bf.id33) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 33;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte4.bf.id33;
                    event_count ++;
                }
                if (g_latest_du.byte4.bf.id34 != latest_du->byte4.bf.id34) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 34;
                    events[event_count].eve_eve_cd.uchar = latest_du->byte4.bf.id34;
                    event_count ++;
                }

                memcpy(&g_latest_du, latest_du, sizeof(DU_t));
            } else if (latest_du->func_cd.uchar == 0x43) { //0x43==C; clear data
                //C
                if (g_latest_du.byte0.bf.id00 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 0;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte0.bf.id01 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 1;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte0.bf.id02 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 2;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte0.bf.id03 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 3;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte0.bf.id04 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 4;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte0.bf.id05 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 5;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte0.bf.id06 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 6;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte0.bf.id07 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 7;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte1.bf.id08 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 8;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte1.bf.id09 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 9;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte1.bf.id10 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 10;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte1.bf.id11 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 11;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte1.bf.id12 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 12;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte1.bf.id13 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 13;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte1.bf.id14 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 14;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte1.bf.id15 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 15;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte2.bf.id16 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 16;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte2.bf.id17 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 17;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte2.bf.id18 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 18;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte2.bf.id19 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 19;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte2.bf.id20 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 20;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte2.bf.id21 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 21;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte2.bf.id22 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 22;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte2.bf.id23 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 23;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte3.bf.id24 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 24;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte3.bf.id25 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 25;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte3.bf.id26 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 26;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte3.bf.id27 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 27;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte3.bf.id28 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 28;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte3.bf.id29 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 29;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte3.bf.id30 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 30;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte3.bf.id31 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 31;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte4.bf.id32 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 32;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte4.bf.id33 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 33;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
                if (g_latest_du.byte4.bf.id34 == FLG_ON) {
                    events[event_count].eve_datetime.ullint = now_ms;
                    events[event_count].eve_type_num.uchar = 34;
                    events[event_count].eve_eve_cd.uchar = FLG_CLEAR;
                    event_count ++;
                }
            }

            if (event_count > 0) {
                insert_event(events,event_count);
            }
        } 
        else 
        {
            usleep(50000);
        }
    }

    return TRUE;
}
2
linuxttyserial-portiot

2 Answers

0
votes

To read from a serial port in a C program, you have to use the OS call select(). When calling that you will "hang" until time-out or some data ready to read.

See Serial Programming Guide for POSIX Operating Systems

0
votes

  1. Look at your variable and parameter types.  ctl_auto_du takes an int * (file descriptor) as a parameter, but you are passing it a FILE * (file pointer).

    • Probably the best (i.e., “right”) way to fix this is to change

      FILE *dental_unit_data;         //new
            ︙
    dental_unit_data = fopen("/dev/ttymxc3", "r"); 

    ctl_auto_du(dental_unit_data); //reads the data from the dental_uni_data

      to

      int   dental_unit_data;         //new
            ︙
    dental_unit_data = open("/dev/ttymxc3", O_RDONLY); 

    ctl_auto_du(&dental_unit_data); //reads the data from the dental_uni_data

    • Alternatively, you could keep dental_unit_data declared as FILE * and keep the fopen, and change the call to ctl_auto_du to

          ctl_auto_du(&fileno(dental_unit_data)); //reads the data …

      although I’m not sure whether that is guaranteed to be portable.

  2. Although the ctl_auto_du function is very long, it looks like all the real I/O work happens in recv_du, and you don’t show us that.  So, if the problem is there, we won’t be able to find it.