====== SDK Script gps2serial-GNSStoGPS.are ====== /* DESC: This script sends the local GPS NMEA stream to the serial interface. * DESC: It checks for the correct CR/LF end of line characters and convert messages $GN to $GP * Copyright (C) 2013-2021) NetModule AG, Switzerland */ /* Options to configure by user*/ SER_SPEED = (int) argv[2]; /* Serial Baud Rate 4800, 9600, 19200, 38400, 57600, 115200 */ SER_DATABIT = 8; /* number of data bits (5, 6, 7, 8) */ SER_STOPBIT = 1; /* number of stop bits (1, 2) */ SER_PARITY = 0; /* parity (0=no parity, 1=odd parity, 2=even parity) */ SER_FLOW = 0; /* flow control (0=none, 1=xon/xoff, 2=hardware) */ DEV = "SERIAL1"; /* name of the Serial Interface */ /* default values */ local_ip = "127.0.0.1"; local_port = (int) nb_config_get("gpsd.0.port"); gpsd = -1; // start serial connection int start_serial() { if (nb_config_get("serial.0.status") != "2") { nb_syslog("serial not assinged to SDK\n"); exit(2); } // printf("set serial attributes\n"); if ((rc = nb_serial_setattr(DEV, SER_SPEED, SER_DATABIT, SER_STOPBIT, SER_PARITY, SER_FLOW)) != 0) { nb_syslog("ERROR: unable to set serial attributes (rc %d) to %s\n", rc, DEV); return -1; } // nb_syslog("Open serial device %s\n", DEV); if ((fd = nb_serial_open(DEV)) < 0) { nb_syslog("ERROR: can't open serial port %s\n", DEV); return -1; } return fd; } // restart GPS deamon int gpsd_restart() { nb_syslog("Restarting GPS daemon"); nb_config_set("gpsd.0.status=0"); do { sleep(3); } while (nb_config_done != 0) nb_config_set("gpsd.0.status=1"); do { sleep(5); } while (nb_config_done != 0) return 0; } // start TCP Socket for GPS deamon loop int gpsd_connect() { nb_syslog("Connecting to GPS daemon"); gpsd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); if (gpsd < 0) { nb_syslog("ERROR: Unable to open socket"); exit(-1); } for (attempt = 0; attempt <= 15; attempt++) { sleep(15); if (connect(gpsd, local_ip, local_port) < 0) { nb_syslog("Could not connect to daemon"); if (attempt == 12) { nb_syslog("Unable to connect, restarting daemon"); gpsd_restart(); } } else { break; } } nb_syslog("Connected to daemon, requesting NMEA"); send(gpsd, "R=1\n"); nb_syslog("Processing NMEA"); return gpsd; } string checksum(string s) { pos = strchr(s, "*"); if (is_void(pos)) return s; /* no checksum to correct */ cs = 0; chars = explode(s); for (i = 1; i < pos; i++) { /* skip $ and *XX */ c = ord(chars[i]); cs ^= c; } r = sprintf("%s%02X%s", substr(s, 0, pos + 1), cs, substr(s, pos + 3)); return r; } /* main() */ if (argc < 2) { usage(); } /* starting serial */ nb_syslog("starting serial"); if ((serial_fd = start_serial()) < 0) { nb_syslog("Could not start serial, exiting\n"); exit(4); } /* process NMEA stream */ nb_syslog("Processing NMEA data"); while (1) { /* connect to gpsd */ if (gpsd < 0) { gpsd = gpsd_connect(gpsd); if (gpsd < 0) { nb_syslog("ERROR: Unable to connect to daemon"); sleep(5); continue; } } /* wait for client socket data */ rv = select(gpsd, 3); if (rv == -1) { nb_syslog("ERROR: select failed, re-connecting"); close(gpsd); gpsd = -1; continue; } else if (rv == 0) { /* nothing received */ continue; } data = recv(gpsd); len = strlen(data); /* Check for correct framing: CR+LF */ if (len > 2) { if (strrchr(data, "\r") != len - 2 || strrchr(data, "\n") != len - 1) { nb_syslog("ERROR: NMEA framing wrong"); close(gpsd); gpsd = -1; gpsd_restart(); continue; } } if (len == 0) { nb_syslog("ERROR: no data, re-connecting"); close(gpsd); gpsd = -1; continue; } /* Convert message $GN to $GP for backward compatibility */ if (strstr(data, "$GN") == 0) { ; a_arr = explode(data); a_arr[2] = "P"; data = checksum(implode(a_arr)); } /* skip all messages different from GPGGA * if(strstr(data,"$GPGGA")==()) * continue; */ sent = write(serial_fd, data, len); nb_syslog("sending Data via serial interface"); if (write(serial_fd, data, len) != len) { nb_syslog("Unable to send message via Serial, data %s, len: %i\n", data, len); } } close(gpsd); close(serial_fd); exit(6);