summaryrefslogtreecommitdiff
path: root/src/ao_gps.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/ao_gps.c')
-rw-r--r--src/ao_gps.c275
1 files changed, 275 insertions, 0 deletions
diff --git a/src/ao_gps.c b/src/ao_gps.c
new file mode 100644
index 00000000..cbde8b48
--- /dev/null
+++ b/src/ao_gps.c
@@ -0,0 +1,275 @@
+/*
+ * Copyright © 2009 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include "ao.h"
+
+#define AO_GPS_LEADER 6
+
+static const char ao_gps_header[] = "GPGGA,";
+__xdata uint8_t ao_gps_mutex;
+static __xdata char ao_gps_char;
+static __xdata uint8_t ao_gps_cksum;
+static __xdata uint8_t ao_gps_error;
+
+__xdata struct ao_gps_data ao_gps_data;
+static __xdata struct ao_gps_data ao_gps_next;
+
+const char ao_gps_config[] =
+ "$PSRF103,00,00,01,01*25\r\n" /* GGA 1 per sec */
+ "$PSRF103,01,00,00,01*25\r\n" /* GLL disable */
+ "$PSRF103,02,00,00,01*26\r\n" /* GSA disable */
+ "$PSRF103,03,00,00,01*27\r\n" /* GSV disable */
+ "$PSRF103,04,00,00,01*20\r\n" /* RMC disable */
+ "$PSRF103,05,00,00,01*21\r\n"; /* VTG disable */
+
+static void
+ao_gps_lexchar(void)
+{
+ if (ao_gps_error)
+ ao_gps_char = '\n';
+ else
+ ao_gps_char = ao_serial_getchar();
+ ao_gps_cksum ^= ao_gps_char;
+}
+
+void
+ao_gps_skip(void)
+{
+ while (ao_gps_char >= '0')
+ ao_gps_lexchar();
+}
+
+void
+ao_gps_skip_field(void)
+{
+ while (ao_gps_char != ',' && ao_gps_char != '*' && ao_gps_char != '\n')
+ ao_gps_lexchar();
+}
+
+void
+ao_gps_skip_sep(void)
+{
+ while (ao_gps_char == ',' || ao_gps_char == '.' || ao_gps_char == '*')
+ ao_gps_lexchar();
+}
+
+__xdata static uint8_t ao_gps_num_width;
+
+static int16_t
+ao_gps_decimal(uint8_t max_width)
+{
+ int16_t v;
+ __xdata uint8_t neg = 0;
+
+ ao_gps_skip_sep();
+ if (ao_gps_char == '-') {
+ neg = 1;
+ ao_gps_lexchar();
+ }
+ v = 0;
+ ao_gps_num_width = 0;
+ while (ao_gps_num_width < max_width) {
+ if (ao_gps_char < '0' || '9' < ao_gps_char)
+ break;
+ v = v * (int16_t) 10 + ao_gps_char - '0';
+ ao_gps_num_width++;
+ ao_gps_lexchar();
+ }
+ if (neg)
+ v = -v;
+ return v;
+}
+
+static uint8_t
+ao_gps_hex(uint8_t max_width)
+{
+ uint8_t v, d;
+
+ ao_gps_skip_sep();
+ v = 0;
+ ao_gps_num_width = 0;
+ while (ao_gps_num_width < max_width) {
+ if ('0' <= ao_gps_char && ao_gps_char <= '9')
+ d = ao_gps_char - '0';
+ else if ('A' <= ao_gps_char && ao_gps_char <= 'F')
+ d = ao_gps_char - 'A' + 10;
+ else if ('a' <= ao_gps_char && ao_gps_char <= 'f')
+ d = ao_gps_char - 'a' + 10;
+ else
+ break;
+ v = (v << 4) | d;
+ ao_gps_num_width++;
+ ao_gps_lexchar();
+ }
+ return v;
+}
+
+static void
+ao_gps_parse_pos(__xdata struct ao_gps_pos * pos, uint8_t deg_width) __reentrant
+{
+ pos->degrees = ao_gps_decimal(deg_width);
+ pos->minutes = ao_gps_decimal(2);
+ if (ao_gps_char == '.') {
+ pos->minutes_fraction = ao_gps_decimal(4);
+ while (ao_gps_num_width < 4) {
+ pos->minutes_fraction *= 10;
+ ao_gps_num_width++;
+ }
+ } else {
+ pos->minutes_fraction = 0;
+ if (ao_gps_char != ',')
+ ao_gps_error = 1;
+ }
+}
+
+static void
+ao_gps_parse_flag(char yes_c, uint8_t yes, char no_c, uint8_t no) __reentrant
+{
+ ao_gps_skip_sep();
+ if (ao_gps_char == yes_c)
+ ao_gps_next.flags |= yes;
+ else if (ao_gps_char == no_c)
+ ao_gps_next.flags |= no;
+ else
+ ao_gps_error = 1;
+ ao_gps_lexchar();
+}
+
+
+void
+ao_gps(void) __reentrant
+{
+ char c;
+ uint8_t i;
+
+ for (i = 0; (c = ao_gps_config[i]); i++)
+ ao_serial_putchar(c);
+ for (;;) {
+ /* Locate the begining of the next record */
+ for (;;) {
+ c = ao_serial_getchar();
+ if (c == '$')
+ break;
+ }
+
+ ao_gps_cksum = 0;
+ ao_gps_error = 0;
+
+ /* Skip anything other than GGA */
+ for (i = 0; i < AO_GPS_LEADER; i++) {
+ ao_gps_lexchar();
+ if (ao_gps_char != ao_gps_header[i])
+ break;
+ }
+ if (i != AO_GPS_LEADER)
+ continue;
+
+ /* Now read the data into the gps data record
+ *
+ * $GPGGA,025149.000,4528.1723,N,12244.2480,W,1,05,2.0,103.5,M,-19.5,M,,0000*66
+ *
+ * Essential fix data
+ *
+ * 025149.000 time (02:51:49.000 GMT)
+ * 4528.1723,N Latitude 45°28.1723' N
+ * 12244.2480,W Longitude 122°44.2480' W
+ * 1 Fix quality:
+ * 0 = invalid
+ * 1 = GPS fix (SPS)
+ * 2 = DGPS fix
+ * 3 = PPS fix
+ * 4 = Real Time Kinematic
+ * 5 = Float RTK
+ * 6 = estimated (dead reckoning)
+ * 7 = Manual input mode
+ * 8 = Simulation mode
+ * 05 Number of satellites (5)
+ * 2.0 Horizontal dilution
+ * 103.5,M Altitude, 103.5M above msl
+ * -19.5,M Height of geoid above WGS84 ellipsoid
+ * ? time in seconds since last DGPS update
+ * 0000 DGPS station ID
+ * *66 checksum
+ */
+
+ ao_gps_next.flags = 0;
+ ao_gps_next.hour = ao_gps_decimal(2);
+ ao_gps_next.minute = ao_gps_decimal(2);
+ ao_gps_next.second = ao_gps_decimal(2);
+ ao_gps_skip_field(); /* skip seconds fraction */
+
+ ao_gps_parse_pos(&ao_gps_next.latitude, 2);
+ ao_gps_parse_flag('N', AO_GPS_LATITUDE_NORTH, 'S', AO_GPS_LATITUDE_SOUTH);
+ ao_gps_parse_pos(&ao_gps_next.longitude, 3);
+ ao_gps_parse_flag('W', AO_GPS_LONGITUDE_WEST, 'E', AO_GPS_LONGITUDE_EAST);
+
+ i = ao_gps_decimal(0xff);
+ if (i == 1)
+ ao_gps_next.flags |= AO_GPS_VALID;
+
+ i = ao_gps_decimal(0xff) << AO_GPS_NUM_SAT_SHIFT;
+ if (i > AO_GPS_NUM_SAT_MASK)
+ i = AO_GPS_NUM_SAT_MASK;
+ ao_gps_next.flags |= i;
+
+ ao_gps_lexchar();
+ ao_gps_skip_field(); /* Horizontal dilution */
+
+ ao_gps_next.altitude = ao_gps_decimal(0xff);
+ ao_gps_skip_field(); /* skip any fractional portion */
+
+ /* Skip remaining fields */
+ while (ao_gps_char != '*' && ao_gps_char != '\n' && ao_gps_char != '\r') {
+ ao_gps_lexchar();
+ ao_gps_skip_field();
+ }
+ if (ao_gps_char == '*') {
+ uint8_t cksum = ao_gps_cksum ^ '*';
+ if (cksum != ao_gps_hex(2))
+ ao_gps_error = 1;
+ } else
+ ao_gps_error = 1;
+ if (!ao_gps_error) {
+ ao_mutex_get(&ao_gps_mutex);
+ memcpy(&ao_gps_data, &ao_gps_next, sizeof (struct ao_gps_data));
+ ao_mutex_put(&ao_gps_mutex);
+ ao_wakeup(&ao_gps_data);
+ }
+ }
+}
+
+__xdata struct ao_task ao_gps_task;
+
+static void
+gps_dump(void) __reentrant
+{
+ ao_mutex_get(&ao_gps_mutex);
+ ao_gps_print(&ao_gps_data);
+ ao_mutex_put(&ao_gps_mutex);
+}
+
+__code struct ao_cmds ao_gps_cmds[] = {
+ { 'g', gps_dump, "g Display current GPS values" },
+ { 0, gps_dump, NULL },
+};
+
+void
+ao_gps_init(void)
+{
+ ao_add_task(&ao_gps_task, ao_gps, "gps");
+ ao_cmd_register(&ao_gps_cmds[0]);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2025-11-04 05:58:00 +0000