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   1 /*
   2  * Copyright © 2009 Keith Packard <keithp@keithp.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; version 2 of the License.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  16  */
  17
  18 #ifndef AO_GPS_TEST
  19 #include "ao.h"
  20 #endif
  21
  22 #define AO_GPS_LEADER           3
  23
  24 static const char ao_gps_header[] = "GPG";
  25
  26 __xdata uint8_t ao_gps_mutex;
  27 static __xdata char ao_gps_char;
  28 static __xdata uint8_t ao_gps_cksum;
  29 static __xdata uint8_t ao_gps_error;
  30
  31 __xdata struct ao_gps_data      ao_gps_data;
  32 __xdata struct ao_gps_tracking_data     ao_gps_tracking_data;
  33
  34 static __xdata struct ao_gps_data               ao_gps_next;
  35 static __xdata struct ao_gps_tracking_data      ao_gps_tracking_next;
  36
  37 static const char ao_gps_config[] = {
  38         0xa0, 0xa1, 0x00, 0x09,         /* length 9 bytes */
  39         0x08,                           /* configure nmea */
  40         1,                              /* gga interval */
  41         1,                              /* gsa interval */
  42         1,                              /* gsv interval */
  43         1,                              /* gll interval */
  44         1,                              /* rmc interval */
  45         1,                              /* vtg interval */
  46         1,                              /* zda interval */
  47         0,                              /* attributes (0 = update to sram, 1 = update flash too) */
  48         0x09, 0x0d, 0x0a,
  49 };
  50
  51 static void
  52 ao_gps_lexchar(void)
  53 {
  54         if (ao_gps_error)
  55                 ao_gps_char = '\n';
  56         else
  57                 ao_gps_char = ao_serial_getchar();
  58         ao_gps_cksum ^= ao_gps_char;
  59 }
  60
  61 void
  62 ao_gps_skip(void)
  63 {
  64         while (ao_gps_char >= '0')
  65                 ao_gps_lexchar();
  66 }
  67
  68 void
  69 ao_gps_skip_field(void)
  70 {
  71         while (ao_gps_char != ',' && ao_gps_char != '*' && ao_gps_char != '\n')
  72                 ao_gps_lexchar();
  73 }
  74
  75 void
  76 ao_gps_skip_sep(void)
  77 {
  78         if (ao_gps_char == ',' || ao_gps_char == '.' || ao_gps_char == '*')
  79                 ao_gps_lexchar();
  80 }
  81
  82 __xdata static uint8_t ao_gps_num_width;
  83
  84 static int16_t
  85 ao_gps_decimal(uint8_t max_width)
  86 {
  87         int16_t v;
  88         __xdata uint8_t neg = 0;
  89
  90         ao_gps_skip_sep();
  91         if (ao_gps_char == '-') {
  92                 neg = 1;
  93                 ao_gps_lexchar();
  94         }
  95         v = 0;
  96         ao_gps_num_width = 0;
  97         while (ao_gps_num_width < max_width) {
  98                 if (ao_gps_char < '0' || '9' < ao_gps_char)
  99                         break;
 100                 v = v * (int16_t) 10 + ao_gps_char - '0';
 101                 ao_gps_num_width++;
 102                 ao_gps_lexchar();
 103         }
 104         if (neg)
 105                 v = -v;
 106         return v;
 107 }
 108
 109 static uint8_t
 110 ao_gps_hex(uint8_t max_width)
 111 {
 112         uint8_t v, d;
 113
 114         ao_gps_skip_sep();
 115         v = 0;
 116         ao_gps_num_width = 0;
 117         while (ao_gps_num_width < max_width) {
 118                 if ('0' <= ao_gps_char && ao_gps_char <= '9')
 119                         d = ao_gps_char - '0';
 120                 else if ('A' <= ao_gps_char && ao_gps_char <= 'F')
 121                         d = ao_gps_char - 'A' + 10;
 122                 else if ('a' <= ao_gps_char && ao_gps_char <= 'f')
 123                         d = ao_gps_char - 'a' + 10;
 124                 else
 125                         break;
 126                 v = (v << 4) | d;
 127                 ao_gps_num_width++;
 128                 ao_gps_lexchar();
 129         }
 130         return v;
 131 }
 132
 133 static int32_t
 134 ao_gps_parse_pos(uint8_t deg_width) __reentrant
 135 {
 136         int32_t d;
 137         int32_t m;
 138         int32_t f;
 139
 140         d = ao_gps_decimal(deg_width);
 141         m = ao_gps_decimal(2);
 142         if (ao_gps_char == '.') {
 143                 f = ao_gps_decimal(4);
 144                 while (ao_gps_num_width < 4) {
 145                         f *= 10;
 146                         ao_gps_num_width++;
 147                 }
 148         } else {
 149                 f = 0;
 150                 if (ao_gps_char != ',')
 151                         ao_gps_error = 1;
 152         }
 153         d = d * 10000000l;
 154         m = m * 10000l + f;
 155         d = d + m * 50 / 3;
 156         return d;
 157 }
 158
 159 static uint8_t
 160 ao_gps_parse_flag(char no_c, char yes_c) __reentrant
 161 {
 162         uint8_t ret = 0;
 163         ao_gps_skip_sep();
 164         if (ao_gps_char == yes_c)
 165                 ret = 1;
 166         else if (ao_gps_char == no_c)
 167                 ret = 0;
 168         else
 169                 ao_gps_error = 1;
 170         ao_gps_lexchar();
 171         return ret;
 172 }
 173
 174
 175 void
 176 ao_gps(void) __reentrant
 177 {
 178         char    c;
 179         uint8_t i;
 180
 181         ao_serial_set_speed(AO_SERIAL_SPEED_9600);
 182         for (i = 0; i < sizeof (ao_gps_config); i++)
 183                 ao_serial_putchar(ao_gps_config[i]);
 184         for (;;) {
 185                 /* Locate the begining of the next record */
 186                 for (;;) {
 187                         c = ao_serial_getchar();
 188                         if (c == '$')
 189                                 break;
 190                 }
 191
 192                 ao_gps_cksum = 0;
 193                 ao_gps_error = 0;
 194
 195                 /* Skip anything other than GPG */
 196                 for (i = 0; i < AO_GPS_LEADER; i++) {
 197                         ao_gps_lexchar();
 198                         if (ao_gps_char != ao_gps_header[i])
 199                                 break;
 200                 }
 201                 if (i != AO_GPS_LEADER)
 202                         continue;
 203
 204                 /* pull the record identifier characters off the link */
 205                 ao_gps_lexchar();
 206                 c = ao_gps_char;
 207                 ao_gps_lexchar();
 208                 i = ao_gps_char;
 209                 ao_gps_lexchar();
 210                 if (ao_gps_char != ',')
 211                         continue;
 212
 213                 if (c == (uint8_t) 'G' && i == (uint8_t) 'A') {
 214                         /* Now read the data into the gps data record
 215                          *
 216                          * $GPGGA,025149.000,4528.1723,N,12244.2480,W,1,05,2.0,103.5,M,-19.5,M,,0000*66
 217                          *
 218                          * Essential fix data
 219                          *
 220                          *         025149.000   time (02:51:49.000 GMT)
 221                          *         4528.1723,N  Latitude 45°28.1723' N
 222                          *         12244.2480,W Longitude 122°44.2480' W
 223                          *         1            Fix quality:
 224                          *                                 0 = invalid
 225                          *                                 1 = GPS fix (SPS)
 226                          *                                 2 = DGPS fix
 227                          *                                 3 = PPS fix
 228                          *                                 4 = Real Time Kinematic
 229                          *                                 5 = Float RTK
 230                          *                                 6 = estimated (dead reckoning)
 231                          *                                 7 = Manual input mode
 232                          *                                 8 = Simulation mode
 233                          *         05           Number of satellites (5)
 234                          *         2.0          Horizontal dilution
 235                          *         103.5,M              Altitude, 103.5M above msl
 236                          *         -19.5,M              Height of geoid above WGS84 ellipsoid
 237                          *         ?            time in seconds since last DGPS update
 238                          *         0000         DGPS station ID
 239                          *         *66          checksum
 240                          */
 241
 242                         ao_gps_next.flags = AO_GPS_RUNNING;
 243                         ao_gps_next.hour = ao_gps_decimal(2);
 244                         ao_gps_next.minute = ao_gps_decimal(2);
 245                         ao_gps_next.second = ao_gps_decimal(2);
 246                         ao_gps_skip_field();    /* skip seconds fraction */
 247
 248                         ao_gps_next.latitude = ao_gps_parse_pos(2);
 249                         if (ao_gps_parse_flag('N', 'S'))
 250                                 ao_gps_next.latitude = -ao_gps_next.latitude;
 251                         ao_gps_next.longitude = ao_gps_parse_pos(3);
 252                         if (ao_gps_parse_flag('E', 'W'))
 253                                 ao_gps_next.longitude = -ao_gps_next.longitude;
 254
 255                         i = ao_gps_decimal(0xff);
 256                         if (i == 1)
 257                                 ao_gps_next.flags |= AO_GPS_VALID;
 258
 259                         i = ao_gps_decimal(0xff) << AO_GPS_NUM_SAT_SHIFT;
 260                         if (i > AO_GPS_NUM_SAT_MASK)
 261                                 i = AO_GPS_NUM_SAT_MASK;
 262                         ao_gps_next.flags |= i;
 263
 264                         ao_gps_lexchar();
 265                         ao_gps_skip_field();    /* Horizontal dilution */
 266
 267                         ao_gps_next.altitude = ao_gps_decimal(0xff);
 268                         ao_gps_skip_field();    /* skip any fractional portion */
 269
 270                         /* Skip remaining fields */
 271                         while (ao_gps_char != '*' && ao_gps_char != '\n' && ao_gps_char != '\r') {
 272                                 ao_gps_lexchar();
 273                                 ao_gps_skip_field();
 274                         }
 275                         if (ao_gps_char == '*') {
 276                                 uint8_t cksum = ao_gps_cksum ^ '*';
 277                                 if (cksum != ao_gps_hex(2))
 278                                         ao_gps_error = 1;
 279                         } else
 280                                 ao_gps_error = 1;
 281                         if (!ao_gps_error) {
 282                                 ao_mutex_get(&ao_gps_mutex);
 283                                 memcpy(&ao_gps_data, &ao_gps_next, sizeof (struct ao_gps_data));
 284                                 ao_mutex_put(&ao_gps_mutex);
 285                                 ao_wakeup(&ao_gps_data);
 286                         }
 287                 } else if (c == (uint8_t) 'S' && i == (uint8_t) 'V') {
 288                         uint8_t done;
 289                         /* Now read the data into the GPS tracking data record
 290                          *
 291                          * $GPGSV,3,1,12,05,54,069,45,12,44,061,44,21,07,184,46,22,78,289,47*72<CR><LF>
 292                          *
 293                          * Satellites in view data
 294                          *
 295                          *      3               Total number of GSV messages
 296                          *      1               Sequence number of current GSV message
 297                          *      12              Total sats in view (0-12)
 298                          *      05              SVID
 299                          *      54              Elevation
 300                          *      069             Azimuth
 301                          *      45              C/N0 in dB
 302                          *      ...             other SVIDs
 303                          *      72              checksum
 304                          */
 305                         c = ao_gps_decimal(1);  /* total messages */
 306                         i = ao_gps_decimal(1);  /* message sequence */
 307                         if (i == 1) {
 308                                 ao_gps_tracking_next.channels = 0;
 309                         }
 310                         done = (uint8_t) c == i;
 311                         ao_gps_lexchar();
 312                         ao_gps_skip_field();    /* sats in view */
 313                         while (ao_gps_char != '*' && ao_gps_char != '\n' && ao_gps_char != '\r') {
 314                                 i = ao_gps_tracking_next.channels;
 315                                 ao_gps_tracking_next.sats[i].svid = ao_gps_decimal(2);  /* SVID */
 316                                 ao_gps_lexchar();
 317                                 ao_gps_skip_field();    /* elevation */
 318                                 ao_gps_lexchar();
 319                                 ao_gps_skip_field();    /* azimuth */
 320                                 if (ao_gps_tracking_next.sats[i].c_n_1 = ao_gps_decimal(2))     /* C/N0 */
 321                                         ao_gps_tracking_next.sats[i].state = 0xbf;
 322                                 else
 323                                         ao_gps_tracking_next.sats[i].state = 0;
 324                                 ao_gps_tracking_next.channels = i + 1;
 325                         }
 326                         if (ao_gps_char == '*') {
 327                                 uint8_t cksum = ao_gps_cksum ^ '*';
 328                                 if (cksum != ao_gps_hex(2))
 329                                         ao_gps_error = 1;
 330                         }
 331                         else
 332                                 ao_gps_error = 1;
 333                         if (ao_gps_error)
 334                                 ao_gps_tracking_next.channels = 0;
 335                         else if (done) {
 336                                 ao_mutex_get(&ao_gps_mutex);
 337                                 memcpy(&ao_gps_tracking_data, &ao_gps_tracking_next,
 338                                        sizeof(ao_gps_tracking_data));
 339                                 ao_mutex_put(&ao_gps_mutex);
 340                                 ao_wakeup(&ao_gps_tracking_data);
 341                         }
 342                 }
 343         }
 344 }
 345
 346 __xdata struct ao_task ao_gps_task;
 347
 348 static void
 349 gps_dump(void) __reentrant
 350 {
 351         ao_mutex_get(&ao_gps_mutex);
 352         ao_gps_print(&ao_gps_data);
 353         putchar('\n');
 354         ao_gps_tracking_print(&ao_gps_tracking_data);
 355         putchar('\n');
 356         ao_mutex_put(&ao_gps_mutex);
 357 }
 358
 359 __code struct ao_cmds ao_gps_cmds[] = {
 360         { 'g', gps_dump,        "g                                  Display current GPS values" },
 361         { 0, gps_dump, NULL },
 362 };
 363
 364 void
 365 ao_gps_init(void)
 366 {
 367         ao_add_task(&ao_gps_task, ao_gps, "gps");
 368         ao_cmd_register(&ao_gps_cmds[0]);
 369 }