Add gps_nmea from https://github.com/xMasterX/all-the-plugins

git-subtree-dir: gps_nmea
git-subtree-mainline: 99df7fbd50deff780246db6edc52b9cafbf6bff6
git-subtree-split: 3758a8da3bfea0efbc3c870fb3b9b937112cfa31

gps_nmea/.gitsubtree

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+https://github.com/xMasterX/all-the-plugins dev base_pack/gps_nmea_uart

gps_nmea/LICENSE

@@ -0,0 +1,674 @@
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
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+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+  16. Limitation of Liability.
+
+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    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, either version 3 of the License, or
+    (at your option) any later version.
+
+    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, see <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<https://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<https://www.gnu.org/licenses/why-not-lgpl.html>.

gps_nmea/README.md

@@ -0,0 +1,46 @@
+# GPS for Flipper Zero
+
+A simple Flipper Zero application for NMEA 0183 serial GPS modules, such as the
+- Adafruit Ultimate GPS Breakout.
+
+Heavy lifting (NMEA parsing) provided by minmea.
+
+## Usage
+
+This is a single-screen app, and a few interactions are provided via the
+hardware buttons:
+
+- Long press the up button to change the **baud rate**. The default baud rate
+  is 9600, but 19200, 38400, 57600, and 115200 baud are also supported.
+- Long press the right button to change **speed units** from knots to
+  kilometers per hour.
+- Press the OK button to set the **backlight** to always on mode. Press it
+  again to disable.
+- Long press the back button to **exit** the app.
+
+## Hardware Setup
+
+Connect the GPS module to power and the USART using GPIO pins 9 (3.3V), 11
+(GND), 13 (TX), and 14 (RX), as appropriate.
+
+
+See the tutorial video - https://www.youtube.com/watch?v=5vSGFzEBp-k from
+Lab401 by RocketGod - https://github.com/RocketGod-git for a visual guide to
+the hardware setup.
+
+## Confirmed Compatible Modules
+
+* Adafruit Ultimate GPS Breakout
+* Beitian BN-180
+* Royaltek RBT-2100LP
+* u-blox NEO-6M
+
+If you have verified this application working with a module not listed here,
+please submit a PR adding it to the list.
+
+## Links
+
+Original repo link - https://github.com/ezod/flipperzero-gps
+Adafruit Ultimate GPS Breakout: https://www.adafruit.com/product/746
+minmea: https://github.com/kosma/minmea
+u-blox NEO-6M: https://www.u-blox.com/en/product/neo-6-series

gps_nmea/application.fam

@@ -0,0 +1,14 @@
+App(
+    appid="gps_nmea",
+    name="[NMEA] GPS",
+    apptype=FlipperAppType.EXTERNAL,
+    entry_point="gps_app",
+    requires=["gui"],
+    stack_size=1 * 1024,
+    order=35,
+    fap_icon="gps_10px.png",
+    fap_category="GPIO",
+    fap_author="@ezod & @xMasterX",
+    fap_version="1.2",
+    fap_description="Works with GPS modules via UART, using NMEA protocol.",
+)

gps_nmea/constants.h

@@ -0,0 +1,4 @@
+#pragma once
+
+#define KNOTS_TO_KPH 1.852
+#define KNOTS_TO_MPH 1.15078

gps_nmea/gps.c

@@ -0,0 +1,212 @@
+#include "gps_uart.h"
+#include "constants.h"
+
+#include <furi.h>
+#include <furi_hal_power.h>
+#include <gui/gui.h>
+#include <string.h>
+
+typedef enum {
+    EventTypeTick,
+    EventTypeKey,
+} EventType;
+
+typedef struct {
+    EventType type;
+    InputEvent input;
+} PluginEvent;
+
+static void render_callback(Canvas* const canvas, void* context) {
+    furi_assert(context);
+    GpsUart* gps_uart = context;
+    furi_mutex_acquire(gps_uart->mutex, FuriWaitForever);
+
+    if(!gps_uart->changing_baudrate) {
+        canvas_set_font(canvas, FontPrimary);
+        canvas_draw_str_aligned(canvas, 32, 8, AlignCenter, AlignBottom, "Latitude");
+        canvas_draw_str_aligned(canvas, 96, 8, AlignCenter, AlignBottom, "Longitude");
+        canvas_draw_str_aligned(canvas, 21, 30, AlignCenter, AlignBottom, "Course");
+        canvas_draw_str_aligned(canvas, 64, 30, AlignCenter, AlignBottom, "Speed");
+        canvas_draw_str_aligned(canvas, 107, 30, AlignCenter, AlignBottom, "Altitude");
+        canvas_draw_str_aligned(canvas, 32, 52, AlignCenter, AlignBottom, "Satellites");
+        canvas_draw_str_aligned(canvas, 96, 52, AlignCenter, AlignBottom, "Last Fix");
+
+        canvas_set_font(canvas, FontSecondary);
+        char buffer[64];
+        snprintf(buffer, 64, "%f", (double)gps_uart->status.latitude);
+        canvas_draw_str_aligned(canvas, 32, 18, AlignCenter, AlignBottom, buffer);
+        snprintf(buffer, 64, "%f", (double)gps_uart->status.longitude);
+        canvas_draw_str_aligned(canvas, 96, 18, AlignCenter, AlignBottom, buffer);
+        snprintf(buffer, 64, "%.1f", (double)gps_uart->status.course);
+        canvas_draw_str_aligned(canvas, 21, 40, AlignCenter, AlignBottom, buffer);
+
+        switch(gps_uart->speed_units) {
+        case KPH:
+            snprintf(buffer, 64, "%.2f km", (double)(gps_uart->status.speed * KNOTS_TO_KPH));
+            break;
+        case MPH:
+            snprintf(buffer, 64, "%.2f mi", (double)(gps_uart->status.speed * KNOTS_TO_MPH));
+            break;
+        case KNOTS:
+        default:
+            snprintf(buffer, 64, "%.2f kn", (double)gps_uart->status.speed);
+            break;
+        }
+
+        canvas_draw_str_aligned(canvas, 64, 40, AlignCenter, AlignBottom, buffer);
+        snprintf(
+            buffer,
+            64,
+            "%.1f %c",
+            (double)gps_uart->status.altitude,
+            tolower(gps_uart->status.altitude_units));
+        canvas_draw_str_aligned(canvas, 107, 40, AlignCenter, AlignBottom, buffer);
+        snprintf(buffer, 64, "%d", gps_uart->status.satellites_tracked);
+        canvas_draw_str_aligned(canvas, 32, 62, AlignCenter, AlignBottom, buffer);
+        snprintf(
+            buffer,
+            64,
+            "%02d:%02d:%02d UTC",
+            gps_uart->status.time_hours,
+            gps_uart->status.time_minutes,
+            gps_uart->status.time_seconds);
+        canvas_draw_str_aligned(canvas, 96, 62, AlignCenter, AlignBottom, buffer);
+    } else {
+        char buffer[64];
+        canvas_set_font(canvas, FontPrimary);
+        canvas_draw_str_aligned(canvas, 64, 32, AlignCenter, AlignBottom, "Baudrate set to:");
+
+        snprintf(buffer, 64, "%ld baud", gps_uart->baudrate);
+        canvas_draw_str_aligned(canvas, 64, 47, AlignCenter, AlignBottom, buffer);
+    }
+
+    furi_mutex_release(gps_uart->mutex);
+}
+
+static void input_callback(InputEvent* input_event, FuriMessageQueue* event_queue) {
+    furi_assert(event_queue);
+
+    PluginEvent event = {.type = EventTypeKey, .input = *input_event};
+    furi_message_queue_put(event_queue, &event, FuriWaitForever);
+}
+
+int32_t gps_app(void* p) {
+    UNUSED(p);
+
+    FuriMessageQueue* event_queue = furi_message_queue_alloc(8, sizeof(PluginEvent));
+
+    uint8_t attempts = 0;
+    bool otg_was_enabled = furi_hal_power_is_otg_enabled();
+    while(!furi_hal_power_is_otg_enabled() && attempts++ < 5) {
+        furi_hal_power_enable_otg();
+        furi_delay_ms(10);
+    }
+    furi_delay_ms(200);
+
+    GpsUart* gps_uart = gps_uart_enable();
+
+    gps_uart->mutex = furi_mutex_alloc(FuriMutexTypeNormal);
+    if(!gps_uart->mutex) {
+        FURI_LOG_E("GPS", "cannot create mutex\r\n");
+        free(gps_uart);
+        return 255;
+    }
+
+    // set system callbacks
+    ViewPort* view_port = view_port_alloc();
+    view_port_draw_callback_set(view_port, render_callback, gps_uart);
+    view_port_input_callback_set(view_port, input_callback, event_queue);
+
+    // open GUI and register view_port
+    Gui* gui = furi_record_open(RECORD_GUI);
+    gui_add_view_port(gui, view_port, GuiLayerFullscreen);
+
+    PluginEvent event;
+    for(bool processing = true; processing;) {
+        FuriStatus event_status = furi_message_queue_get(event_queue, &event, 100);
+
+        furi_mutex_acquire(gps_uart->mutex, FuriWaitForever);
+
+        if(event_status == FuriStatusOk) {
+            // press events
+            if(event.type == EventTypeKey) {
+                if(event.input.type == InputTypeShort) {
+                    switch(event.input.key) {
+                    case InputKeyUp:
+                    case InputKeyDown:
+                    case InputKeyRight:
+                    case InputKeyLeft:
+                    case InputKeyBack:
+                        break;
+                    case InputKeyOk:
+                        if(!gps_uart->backlight_on) {
+                            notification_message_block(
+                                gps_uart->notifications, &sequence_display_backlight_enforce_on);
+                            gps_uart->backlight_on = true;
+                        } else {
+                            notification_message_block(
+                                gps_uart->notifications, &sequence_display_backlight_enforce_auto);
+                            notification_message(
+                                gps_uart->notifications, &sequence_display_backlight_off);
+                            gps_uart->backlight_on = false;
+                        }
+                        break;
+                    default:
+                        break;
+                    }
+                } else if(event.input.type == InputTypeLong) {
+                    switch(event.input.key) {
+                    case InputKeyUp:
+                        gps_uart_deinit_thread(gps_uart);
+                        const int baudrate_length =
+                            sizeof(gps_baudrates) / sizeof(gps_baudrates[0]);
+                        current_gps_baudrate++;
+                        if(current_gps_baudrate >= baudrate_length) {
+                            current_gps_baudrate = 0;
+                        }
+                        gps_uart->baudrate = gps_baudrates[current_gps_baudrate];
+
+                        gps_uart_init_thread(gps_uart);
+                        gps_uart->changing_baudrate = true;
+                        furi_mutex_release(gps_uart->mutex);
+                        view_port_update(view_port);
+                        break;
+                    case InputKeyRight:
+                        gps_uart->speed_units++;
+                        if(gps_uart->speed_units == INVALID) {
+                            gps_uart->speed_units = KNOTS;
+                        }
+                        break;
+                    case InputKeyBack:
+                        processing = false;
+                        break;
+                    default:
+                        break;
+                    }
+                }
+            }
+        }
+        if(!gps_uart->changing_baudrate) {
+            furi_mutex_release(gps_uart->mutex);
+            view_port_update(view_port);
+        } else {
+            furi_delay_ms(1000);
+            gps_uart->changing_baudrate = false;
+        }
+    }
+
+    notification_message_block(gps_uart->notifications, &sequence_display_backlight_enforce_auto);
+    view_port_enabled_set(view_port, false);
+    gui_remove_view_port(gui, view_port);
+    furi_record_close(RECORD_GUI);
+    view_port_free(view_port);
+    furi_message_queue_free(event_queue);
+    furi_mutex_free(gps_uart->mutex);
+    gps_uart_disable(gps_uart);
+
+    if(furi_hal_power_is_otg_enabled() && !otg_was_enabled) {
+        furi_hal_power_disable_otg();
+    }
+
+    return 0;
+}

gps_nmea/gps_uart.c

@@ -0,0 +1,220 @@
+#include <string.h>
+
+#include "minmea.h"
+#include "gps_uart.h"
+
+typedef enum {
+    WorkerEvtStop = (1 << 0),
+    WorkerEvtRxDone = (1 << 1),
+} WorkerEvtFlags;
+
+#define WORKER_ALL_RX_EVENTS (WorkerEvtStop | WorkerEvtRxDone)
+
+static void gps_uart_on_irq_cb(UartIrqEvent ev, uint8_t data, void* context) {
+    GpsUart* gps_uart = (GpsUart*)context;
+
+    if(ev == UartIrqEventRXNE) {
+        furi_stream_buffer_send(gps_uart->rx_stream, &data, 1, 0);
+        furi_thread_flags_set(furi_thread_get_id(gps_uart->thread), WorkerEvtRxDone);
+    }
+}
+
+static void gps_uart_serial_init(GpsUart* gps_uart) {
+    furi_hal_console_disable();
+    furi_hal_uart_set_irq_cb(FuriHalUartIdUSART1, gps_uart_on_irq_cb, gps_uart);
+    furi_hal_uart_set_br(FuriHalUartIdUSART1, gps_uart->baudrate);
+}
+
+static void gps_uart_serial_deinit(GpsUart* gps_uart) {
+    UNUSED(gps_uart);
+    furi_hal_uart_set_irq_cb(FuriHalUartIdUSART1, NULL, NULL);
+    furi_hal_console_enable();
+}
+
+static void gps_uart_parse_nmea(GpsUart* gps_uart, char* line) {
+    switch(minmea_sentence_id(line, false)) {
+    case MINMEA_SENTENCE_RMC: {
+        struct minmea_sentence_rmc frame;
+        if(minmea_parse_rmc(&frame, line)) {
+            gps_uart->status.valid = frame.valid;
+            gps_uart->status.latitude = minmea_tocoord(&frame.latitude);
+            gps_uart->status.longitude = minmea_tocoord(&frame.longitude);
+            gps_uart->status.speed = minmea_tofloat(&frame.speed);
+            gps_uart->status.course = minmea_tofloat(&frame.course);
+            gps_uart->status.time_hours = frame.time.hours;
+            gps_uart->status.time_minutes = frame.time.minutes;
+            gps_uart->status.time_seconds = frame.time.seconds;
+
+            notification_message_block(gps_uart->notifications, &sequence_blink_green_10);
+        }
+    } break;
+
+    case MINMEA_SENTENCE_GGA: {
+        struct minmea_sentence_gga frame;
+        if(minmea_parse_gga(&frame, line)) {
+            gps_uart->status.latitude = minmea_tocoord(&frame.latitude);
+            gps_uart->status.longitude = minmea_tocoord(&frame.longitude);
+            gps_uart->status.altitude = minmea_tofloat(&frame.altitude);
+            gps_uart->status.altitude_units = frame.altitude_units;
+            gps_uart->status.fix_quality = frame.fix_quality;
+            gps_uart->status.satellites_tracked = frame.satellites_tracked;
+            gps_uart->status.time_hours = frame.time.hours;
+            gps_uart->status.time_minutes = frame.time.minutes;
+            gps_uart->status.time_seconds = frame.time.seconds;
+
+            notification_message_block(gps_uart->notifications, &sequence_blink_magenta_10);
+        }
+    } break;
+
+    case MINMEA_SENTENCE_GLL: {
+        struct minmea_sentence_gll frame;
+        if(minmea_parse_gll(&frame, line)) {
+            gps_uart->status.latitude = minmea_tocoord(&frame.latitude);
+            gps_uart->status.longitude = minmea_tocoord(&frame.longitude);
+            gps_uart->status.time_hours = frame.time.hours;
+            gps_uart->status.time_minutes = frame.time.minutes;
+            gps_uart->status.time_seconds = frame.time.seconds;
+
+            notification_message_block(gps_uart->notifications, &sequence_blink_red_10);
+        }
+    } break;
+
+    default:
+        break;
+    }
+}
+
+static int32_t gps_uart_worker(void* context) {
+    GpsUart* gps_uart = (GpsUart*)context;
+
+    size_t rx_offset = 0;
+
+    while(1) {
+        uint32_t events =
+            furi_thread_flags_wait(WORKER_ALL_RX_EVENTS, FuriFlagWaitAny, FuriWaitForever);
+        furi_check((events & FuriFlagError) == 0);
+
+        if(events & WorkerEvtStop) {
+            break;
+        }
+
+        if(events & WorkerEvtRxDone) {
+            size_t len = 0;
+            do {
+                // receive serial bytes into rx_buf, starting at rx_offset from the start of the buffer
+                // the maximum we can receive is RX_BUF_SIZE - 1 - rx_offset
+                len = furi_stream_buffer_receive(
+                    gps_uart->rx_stream,
+                    gps_uart->rx_buf + rx_offset,
+                    RX_BUF_SIZE - 1 - rx_offset,
+                    0);
+                if(len > 0) {
+                    // increase rx_offset by the number of bytes received, and null-terminate rx_buf
+                    rx_offset += len;
+                    gps_uart->rx_buf[rx_offset] = '\0';
+
+                    // look for strings ending in newlines, starting at the start of rx_buf
+                    char* line_current = (char*)gps_uart->rx_buf;
+                    while(1) {
+                        // skip null characters
+                        while(*line_current == '\0' &&
+                              line_current < (char*)gps_uart->rx_buf + rx_offset - 1) {
+                            line_current++;
+                        }
+
+                        // find the next newline
+                        char* newline = strchr(line_current, '\n');
+                        if(newline) // newline found
+                        {
+                            // put a null terminator in place of the newline, to delimit the line string
+                            *newline = '\0';
+
+                            // attempt to parse the line as a NMEA sentence
+                            gps_uart_parse_nmea(gps_uart, line_current);
+
+                            // move the cursor to the character after the newline
+                            line_current = newline + 1;
+                        } else // no more newlines found
+                        {
+                            if(line_current >
+                               (char*)gps_uart->rx_buf) // at least one line was found
+                            {
+                                // clear parsed lines, and move any leftover bytes to the start of rx_buf
+                                rx_offset = 0;
+                                while(
+                                    *line_current) // stop when the original rx_offset terminator is reached
+                                {
+                                    gps_uart->rx_buf[rx_offset++] = *(line_current++);
+                                }
+                            }
+                            break; // go back to receiving bytes from the serial stream
+                        }
+                    }
+                }
+            } while(len > 0);
+        }
+    }
+
+    gps_uart_serial_deinit(gps_uart);
+    furi_stream_buffer_free(gps_uart->rx_stream);
+
+    return 0;
+}
+
+void gps_uart_init_thread(GpsUart* gps_uart) {
+    furi_assert(gps_uart);
+    gps_uart->status.valid = false;
+    gps_uart->status.latitude = 0.0;
+    gps_uart->status.longitude = 0.0;
+    gps_uart->status.speed = 0.0;
+    gps_uart->status.course = 0.0;
+    gps_uart->status.altitude = 0.0;
+    gps_uart->status.altitude_units = ' ';
+    gps_uart->status.fix_quality = 0;
+    gps_uart->status.satellites_tracked = 0;
+    gps_uart->status.time_hours = 0;
+    gps_uart->status.time_minutes = 0;
+    gps_uart->status.time_seconds = 0;
+
+    gps_uart->rx_stream = furi_stream_buffer_alloc(RX_BUF_SIZE * 5, 1);
+
+    gps_uart->thread = furi_thread_alloc();
+    furi_thread_set_name(gps_uart->thread, "GpsUartWorker");
+    furi_thread_set_stack_size(gps_uart->thread, 1024);
+    furi_thread_set_context(gps_uart->thread, gps_uart);
+    furi_thread_set_callback(gps_uart->thread, gps_uart_worker);
+
+    furi_thread_start(gps_uart->thread);
+
+    gps_uart_serial_init(gps_uart);
+}
+
+void gps_uart_deinit_thread(GpsUart* gps_uart) {
+    furi_assert(gps_uart);
+    furi_thread_flags_set(furi_thread_get_id(gps_uart->thread), WorkerEvtStop);
+    furi_thread_join(gps_uart->thread);
+    furi_thread_free(gps_uart->thread);
+}
+
+GpsUart* gps_uart_enable() {
+    GpsUart* gps_uart = malloc(sizeof(GpsUart));
+
+    gps_uart->notifications = furi_record_open(RECORD_NOTIFICATION);
+
+    gps_uart->baudrate = gps_baudrates[current_gps_baudrate];
+    gps_uart->changing_baudrate = false;
+    gps_uart->backlight_on = false;
+    gps_uart->speed_units = KNOTS;
+
+    gps_uart_init_thread(gps_uart);
+
+    return gps_uart;
+}
+
+void gps_uart_disable(GpsUart* gps_uart) {
+    furi_assert(gps_uart);
+    gps_uart_deinit_thread(gps_uart);
+    furi_record_close(RECORD_NOTIFICATION);
+
+    free(gps_uart);
+}

gps_nmea/gps_uart.h

@@ -0,0 +1,48 @@
+#pragma once
+
+#include <furi_hal.h>
+#include <notification/notification_messages.h>
+
+#define RX_BUF_SIZE 1024
+
+static const int gps_baudrates[6] = {4800, 9600, 19200, 38400, 57600, 115200};
+static int current_gps_baudrate = 1;
+
+typedef struct {
+    bool valid;
+    float latitude;
+    float longitude;
+    float speed;
+    float course;
+    float altitude;
+    char altitude_units;
+    int fix_quality;
+    int satellites_tracked;
+    int time_hours;
+    int time_minutes;
+    int time_seconds;
+} GpsStatus;
+
+typedef enum { KNOTS, KPH, MPH, INVALID } SpeedUnit;
+
+typedef struct {
+    FuriMutex* mutex;
+    FuriThread* thread;
+    FuriStreamBuffer* rx_stream;
+    uint8_t rx_buf[RX_BUF_SIZE];
+
+    NotificationApp* notifications;
+    uint32_t baudrate;
+    bool changing_baudrate;
+    bool backlight_on;
+    SpeedUnit speed_units;
+
+    GpsStatus status;
+} GpsUart;
+
+void gps_uart_init_thread(GpsUart* gps_uart);
+void gps_uart_deinit_thread(GpsUart* gps_uart);
+
+GpsUart* gps_uart_enable();
+
+void gps_uart_disable(GpsUart* gps_uart);

gps_nmea/minmea.c

@@ -0,0 +1,640 @@
+/*
+ * Copyright © 2014 Kosma Moczek <kosma@cloudyourcar.com>
+ * This program is free software. It comes without any warranty, to the extent
+ * permitted by applicable law. You can redistribute it and/or modify it under
+ * the terms of the Do What The Fuck You Want To Public License, Version 2, as
+ * published by Sam Hocevar. See the COPYING file for more details.
+ */
+
+#include "minmea.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdarg.h>
+
+#define boolstr(s) ((s) ? "true" : "false")
+
+static int hex2int(char c) {
+    if(c >= '0' && c <= '9') return c - '0';
+    if(c >= 'A' && c <= 'F') return c - 'A' + 10;
+    if(c >= 'a' && c <= 'f') return c - 'a' + 10;
+    return -1;
+}
+
+uint8_t minmea_checksum(const char* sentence) {
+    // Support senteces with or without the starting dollar sign.
+    if(*sentence == '$') sentence++;
+
+    uint8_t checksum = 0x00;
+
+    // The optional checksum is an XOR of all bytes between "$" and "*".
+    while(*sentence && *sentence != '*') checksum ^= *sentence++;
+
+    return checksum;
+}
+
+bool minmea_check(const char* sentence, bool strict) {
+    uint8_t checksum = 0x00;
+
+    // A valid sentence starts with "$".
+    if(*sentence++ != '$') return false;
+
+    // The optional checksum is an XOR of all bytes between "$" and "*".
+    while(*sentence && *sentence != '*' && isprint((unsigned char)*sentence))
+        checksum ^= *sentence++;
+
+    // If checksum is present...
+    if(*sentence == '*') {
+        // Extract checksum.
+        sentence++;
+        int upper = hex2int(*sentence++);
+        if(upper == -1) return false;
+        int lower = hex2int(*sentence++);
+        if(lower == -1) return false;
+        int expected = upper << 4 | lower;
+
+        // Check for checksum mismatch.
+        if(checksum != expected) return false;
+    } else if(strict) {
+        // Discard non-checksummed frames in strict mode.
+        return false;
+    }
+
+    // The only stuff allowed at this point is a newline.
+    while(*sentence == '\r' || *sentence == '\n') {
+        sentence++;
+    }
+
+    if(*sentence) {
+        return false;
+    }
+
+    return true;
+}
+
+bool minmea_scan(const char* sentence, const char* format, ...) {
+    bool result = false;
+    bool optional = false;
+
+    if(sentence == NULL) return false;
+
+    va_list ap;
+    va_start(ap, format);
+
+    const char* field = sentence;
+#define next_field()                                 \
+    do {                                             \
+        /* Progress to the next field. */            \
+        while(minmea_isfield(*sentence)) sentence++; \
+        /* Make sure there is a field there. */      \
+        if(*sentence == ',') {                       \
+            sentence++;                              \
+            field = sentence;                        \
+        } else {                                     \
+            field = NULL;                            \
+        }                                            \
+    } while(0)
+
+    while(*format) {
+        char type = *format++;
+
+        if(type == ';') {
+            // All further fields are optional.
+            optional = true;
+            continue;
+        }
+
+        if(!field && !optional) {
+            // Field requested but we ran out if input. Bail out.
+            goto parse_error;
+        }
+
+        switch(type) {
+        case 'c': { // Single character field (char).
+            char value = '\0';
+
+            if(field && minmea_isfield(*field)) value = *field;
+
+            *va_arg(ap, char*) = value;
+        } break;
+
+        case 'd': { // Single character direction field (int).
+            int value = 0;
+
+            if(field && minmea_isfield(*field)) {
+                switch(*field) {
+                case 'N':
+                case 'E':
+                    value = 1;
+                    break;
+                case 'S':
+                case 'W':
+                    value = -1;
+                    break;
+                default:
+                    goto parse_error;
+                }
+            }
+
+            *va_arg(ap, int*) = value;
+        } break;
+
+        case 'f': { // Fractional value with scale (struct minmea_float).
+            int sign = 0;
+            int_least32_t value = -1;
+            int_least32_t scale = 0;
+
+            if(field) {
+                while(minmea_isfield(*field)) {
+                    if(*field == '+' && !sign && value == -1) {
+                        sign = 1;
+                    } else if(*field == '-' && !sign && value == -1) {
+                        sign = -1;
+                    } else if(isdigit((unsigned char)*field)) {
+                        int digit = *field - '0';
+                        if(value == -1) value = 0;
+                        if(value > (INT_LEAST32_MAX - digit) / 10) {
+                            /* we ran out of bits, what do we do? */
+                            if(scale) {
+                                /* truncate extra precision */
+                                break;
+                            } else {
+                                /* integer overflow. bail out. */
+                                goto parse_error;
+                            }
+                        }
+                        value = (10 * value) + digit;
+                        if(scale) scale *= 10;
+                    } else if(*field == '.' && scale == 0) {
+                        scale = 1;
+                    } else if(*field == ' ') {
+                        /* Allow spaces at the start of the field. Not NMEA
+                             * conformant, but some modules do this. */
+                        if(sign != 0 || value != -1 || scale != 0) goto parse_error;
+                    } else {
+                        goto parse_error;
+                    }
+                    field++;
+                }
+            }
+
+            if((sign || scale) && value == -1) goto parse_error;
+
+            if(value == -1) {
+                /* No digits were scanned. */
+                value = 0;
+                scale = 0;
+            } else if(scale == 0) {
+                /* No decimal point. */
+                scale = 1;
+            }
+            if(sign) value *= sign;
+
+            *va_arg(ap, struct minmea_float*) = (struct minmea_float){value, scale};
+        } break;
+
+        case 'i': { // Integer value, default 0 (int).
+            int value = 0;
+
+            if(field) {
+                char* endptr;
+                value = strtol(field, &endptr, 10);
+                if(minmea_isfield(*endptr)) goto parse_error;
+            }
+
+            *va_arg(ap, int*) = value;
+        } break;
+
+        case 's': { // String value (char *).
+            char* buf = va_arg(ap, char*);
+
+            if(field) {
+                while(minmea_isfield(*field)) *buf++ = *field++;
+            }
+
+            *buf = '\0';
+        } break;
+
+        case 't': { // NMEA talker+sentence identifier (char *).
+            // This field is always mandatory.
+            if(!field) goto parse_error;
+
+            if(field[0] != '$') goto parse_error;
+            for(int f = 0; f < 5; f++)
+                if(!minmea_isfield(field[1 + f])) goto parse_error;
+
+            char* buf = va_arg(ap, char*);
+            memcpy(buf, field + 1, 5);
+            buf[5] = '\0';
+        } break;
+
+        case 'D': { // Date (int, int, int), -1 if empty.
+            struct minmea_date* date = va_arg(ap, struct minmea_date*);
+
+            int d = -1, m = -1, y = -1;
+
+            if(field && minmea_isfield(*field)) {
+                // Always six digits.
+                for(int f = 0; f < 6; f++)
+                    if(!isdigit((unsigned char)field[f])) goto parse_error;
+
+                char dArr[] = {field[0], field[1], '\0'};
+                char mArr[] = {field[2], field[3], '\0'};
+                char yArr[] = {field[4], field[5], '\0'};
+                d = strtol(dArr, NULL, 10);
+                m = strtol(mArr, NULL, 10);
+                y = strtol(yArr, NULL, 10);
+            }
+
+            date->day = d;
+            date->month = m;
+            date->year = y;
+        } break;
+
+        case 'T': { // Time (int, int, int, int), -1 if empty.
+            struct minmea_time* time_ = va_arg(ap, struct minmea_time*);
+
+            int h = -1, i = -1, s = -1, u = -1;
+
+            if(field && minmea_isfield(*field)) {
+                // Minimum required: integer time.
+                for(int f = 0; f < 6; f++)
+                    if(!isdigit((unsigned char)field[f])) goto parse_error;
+
+                char hArr[] = {field[0], field[1], '\0'};
+                char iArr[] = {field[2], field[3], '\0'};
+                char sArr[] = {field[4], field[5], '\0'};
+                h = strtol(hArr, NULL, 10);
+                i = strtol(iArr, NULL, 10);
+                s = strtol(sArr, NULL, 10);
+                field += 6;
+
+                // Extra: fractional time. Saved as microseconds.
+                if(*field++ == '.') {
+                    uint32_t value = 0;
+                    uint32_t scale = 1000000LU;
+                    while(isdigit((unsigned char)*field) && scale > 1) {
+                        value = (value * 10) + (*field++ - '0');
+                        scale /= 10;
+                    }
+                    u = value * scale;
+                } else {
+                    u = 0;
+                }
+            }
+
+            time_->hours = h;
+            time_->minutes = i;
+            time_->seconds = s;
+            time_->microseconds = u;
+        } break;
+
+        case '_': { // Ignore the field.
+        } break;
+
+        default: { // Unknown.
+            goto parse_error;
+        }
+        }
+
+        next_field();
+    }
+
+    result = true;
+
+parse_error:
+    va_end(ap);
+    return result;
+}
+
+bool minmea_talker_id(char talker[3], const char* sentence) {
+    char type[6];
+    if(!minmea_scan(sentence, "t", type)) return false;
+
+    talker[0] = type[0];
+    talker[1] = type[1];
+    talker[2] = '\0';
+
+    return true;
+}
+
+enum minmea_sentence_id minmea_sentence_id(const char* sentence, bool strict) {
+    if(!minmea_check(sentence, strict)) return MINMEA_INVALID;
+
+    char type[6];
+    if(!minmea_scan(sentence, "t", type)) return MINMEA_INVALID;
+
+    if(!strcmp(type + 2, "GBS")) return MINMEA_SENTENCE_GBS;
+    if(!strcmp(type + 2, "GGA")) return MINMEA_SENTENCE_GGA;
+    if(!strcmp(type + 2, "GLL")) return MINMEA_SENTENCE_GLL;
+    if(!strcmp(type + 2, "GSA")) return MINMEA_SENTENCE_GSA;
+    if(!strcmp(type + 2, "GST")) return MINMEA_SENTENCE_GST;
+    if(!strcmp(type + 2, "GSV")) return MINMEA_SENTENCE_GSV;
+    if(!strcmp(type + 2, "RMC")) return MINMEA_SENTENCE_RMC;
+    if(!strcmp(type + 2, "VTG")) return MINMEA_SENTENCE_VTG;
+    if(!strcmp(type + 2, "ZDA")) return MINMEA_SENTENCE_ZDA;
+
+    return MINMEA_UNKNOWN;
+}
+
+bool minmea_parse_gbs(struct minmea_sentence_gbs* frame, const char* sentence) {
+    // $GNGBS,170556.00,3.0,2.9,8.3,,,,*5C
+    char type[6];
+    if(!minmea_scan(
+           sentence,
+           "tTfffifff",
+           type,
+           &frame->time,
+           &frame->err_latitude,
+           &frame->err_longitude,
+           &frame->err_altitude,
+           &frame->svid,
+           &frame->prob,
+           &frame->bias,
+           &frame->stddev))
+        return false;
+    if(strcmp(type + 2, "GBS")) return false;
+
+    return true;
+}
+
+bool minmea_parse_rmc(struct minmea_sentence_rmc* frame, const char* sentence) {
+    // $GPRMC,081836,A,3751.65,S,14507.36,E,000.0,360.0,130998,011.3,E*62
+    char type[6];
+    char validity;
+    int latitude_direction;
+    int longitude_direction;
+    int variation_direction;
+    if(!minmea_scan(
+           sentence,
+           "tTcfdfdffDfd",
+           type,
+           &frame->time,
+           &validity,
+           &frame->latitude,
+           &latitude_direction,
+           &frame->longitude,
+           &longitude_direction,
+           &frame->speed,
+           &frame->course,
+           &frame->date,
+           &frame->variation,
+           &variation_direction))
+        return false;
+    if(strcmp(type + 2, "RMC")) return false;
+
+    frame->valid = (validity == 'A');
+    frame->latitude.value *= latitude_direction;
+    frame->longitude.value *= longitude_direction;
+    frame->variation.value *= variation_direction;
+
+    return true;
+}
+
+bool minmea_parse_gga(struct minmea_sentence_gga* frame, const char* sentence) {
+    // $GPGGA,123519,4807.038,N,01131.000,E,1,08,0.9,545.4,M,46.9,M,,*47
+    char type[6];
+    int latitude_direction;
+    int longitude_direction;
+
+    if(!minmea_scan(
+           sentence,
+           "tTfdfdiiffcfcf_",
+           type,
+           &frame->time,
+           &frame->latitude,
+           &latitude_direction,
+           &frame->longitude,
+           &longitude_direction,
+           &frame->fix_quality,
+           &frame->satellites_tracked,
+           &frame->hdop,
+           &frame->altitude,
+           &frame->altitude_units,
+           &frame->height,
+           &frame->height_units,
+           &frame->dgps_age))
+        return false;
+    if(strcmp(type + 2, "GGA")) return false;
+
+    frame->latitude.value *= latitude_direction;
+    frame->longitude.value *= longitude_direction;
+
+    return true;
+}
+
+bool minmea_parse_gsa(struct minmea_sentence_gsa* frame, const char* sentence) {
+    // $GPGSA,A,3,04,05,,09,12,,,24,,,,,2.5,1.3,2.1*39
+    char type[6];
+
+    if(!minmea_scan(
+           sentence,
+           "tciiiiiiiiiiiiifff",
+           type,
+           &frame->mode,
+           &frame->fix_type,
+           &frame->sats[0],
+           &frame->sats[1],
+           &frame->sats[2],
+           &frame->sats[3],
+           &frame->sats[4],
+           &frame->sats[5],
+           &frame->sats[6],
+           &frame->sats[7],
+           &frame->sats[8],
+           &frame->sats[9],
+           &frame->sats[10],
+           &frame->sats[11],
+           &frame->pdop,
+           &frame->hdop,
+           &frame->vdop))
+        return false;
+    if(strcmp(type + 2, "GSA")) return false;
+
+    return true;
+}
+
+bool minmea_parse_gll(struct minmea_sentence_gll* frame, const char* sentence) {
+    // $GPGLL,3723.2475,N,12158.3416,W,161229.487,A,A*41$;
+    char type[6];
+    int latitude_direction;
+    int longitude_direction;
+
+    if(!minmea_scan(
+           sentence,
+           "tfdfdTc;c",
+           type,
+           &frame->latitude,
+           &latitude_direction,
+           &frame->longitude,
+           &longitude_direction,
+           &frame->time,
+           &frame->status,
+           &frame->mode))
+        return false;
+    if(strcmp(type + 2, "GLL")) return false;
+
+    frame->latitude.value *= latitude_direction;
+    frame->longitude.value *= longitude_direction;
+
+    return true;
+}
+
+bool minmea_parse_gst(struct minmea_sentence_gst* frame, const char* sentence) {
+    // $GPGST,024603.00,3.2,6.6,4.7,47.3,5.8,5.6,22.0*58
+    char type[6];
+
+    if(!minmea_scan(
+           sentence,
+           "tTfffffff",
+           type,
+           &frame->time,
+           &frame->rms_deviation,
+           &frame->semi_major_deviation,
+           &frame->semi_minor_deviation,
+           &frame->semi_major_orientation,
+           &frame->latitude_error_deviation,
+           &frame->longitude_error_deviation,
+           &frame->altitude_error_deviation))
+        return false;
+    if(strcmp(type + 2, "GST")) return false;
+
+    return true;
+}
+
+bool minmea_parse_gsv(struct minmea_sentence_gsv* frame, const char* sentence) {
+    // $GPGSV,3,1,11,03,03,111,00,04,15,270,00,06,01,010,00,13,06,292,00*74
+    // $GPGSV,3,3,11,22,42,067,42,24,14,311,43,27,05,244,00,,,,*4D
+    // $GPGSV,4,2,11,08,51,203,30,09,45,215,28*75
+    // $GPGSV,4,4,13,39,31,170,27*40
+    // $GPGSV,4,4,13*7B
+    char type[6];
+
+    if(!minmea_scan(
+           sentence,
+           "tiii;iiiiiiiiiiiiiiii",
+           type,
+           &frame->total_msgs,
+           &frame->msg_nr,
+           &frame->total_sats,
+           &frame->sats[0].nr,
+           &frame->sats[0].elevation,
+           &frame->sats[0].azimuth,
+           &frame->sats[0].snr,
+           &frame->sats[1].nr,
+           &frame->sats[1].elevation,
+           &frame->sats[1].azimuth,
+           &frame->sats[1].snr,
+           &frame->sats[2].nr,
+           &frame->sats[2].elevation,
+           &frame->sats[2].azimuth,
+           &frame->sats[2].snr,
+           &frame->sats[3].nr,
+           &frame->sats[3].elevation,
+           &frame->sats[3].azimuth,
+           &frame->sats[3].snr)) {
+        return false;
+    }
+    if(strcmp(type + 2, "GSV")) return false;
+
+    return true;
+}
+
+bool minmea_parse_vtg(struct minmea_sentence_vtg* frame, const char* sentence) {
+    // $GPVTG,054.7,T,034.4,M,005.5,N,010.2,K*48
+    // $GPVTG,156.1,T,140.9,M,0.0,N,0.0,K*41
+    // $GPVTG,096.5,T,083.5,M,0.0,N,0.0,K,D*22
+    // $GPVTG,188.36,T,,M,0.820,N,1.519,K,A*3F
+    char type[6];
+    char c_true, c_magnetic, c_knots, c_kph, c_faa_mode;
+
+    if(!minmea_scan(
+           sentence,
+           "t;fcfcfcfcc",
+           type,
+           &frame->true_track_degrees,
+           &c_true,
+           &frame->magnetic_track_degrees,
+           &c_magnetic,
+           &frame->speed_knots,
+           &c_knots,
+           &frame->speed_kph,
+           &c_kph,
+           &c_faa_mode))
+        return false;
+    if(strcmp(type + 2, "VTG")) return false;
+    // values are only valid with the accompanying characters
+    if(c_true != 'T') frame->true_track_degrees.scale = 0;
+    if(c_magnetic != 'M') frame->magnetic_track_degrees.scale = 0;
+    if(c_knots != 'N') frame->speed_knots.scale = 0;
+    if(c_kph != 'K') frame->speed_kph.scale = 0;
+    frame->faa_mode = (enum minmea_faa_mode)c_faa_mode;
+
+    return true;
+}
+
+bool minmea_parse_zda(struct minmea_sentence_zda* frame, const char* sentence) {
+    // $GPZDA,201530.00,04,07,2002,00,00*60
+    char type[6];
+
+    if(!minmea_scan(
+           sentence,
+           "tTiiiii",
+           type,
+           &frame->time,
+           &frame->date.day,
+           &frame->date.month,
+           &frame->date.year,
+           &frame->hour_offset,
+           &frame->minute_offset))
+        return false;
+    if(strcmp(type + 2, "ZDA")) return false;
+
+    // check offsets
+    if(abs(frame->hour_offset) > 13 || frame->minute_offset > 59 || frame->minute_offset < 0)
+        return false;
+
+    return true;
+}
+
+int minmea_getdatetime(
+    struct tm* tm,
+    const struct minmea_date* date,
+    const struct minmea_time* time_) {
+    if(date->year == -1 || time_->hours == -1) return -1;
+
+    memset(tm, 0, sizeof(*tm));
+    if(date->year < 80) {
+        tm->tm_year = 2000 + date->year - 1900; // 2000-2079
+    } else if(date->year >= 1900) {
+        tm->tm_year = date->year - 1900; // 4 digit year, use directly
+    } else {
+        tm->tm_year = date->year; // 1980-1999
+    }
+    tm->tm_mon = date->month - 1;
+    tm->tm_mday = date->day;
+    tm->tm_hour = time_->hours;
+    tm->tm_min = time_->minutes;
+    tm->tm_sec = time_->seconds;
+
+    return 0;
+}
+
+int minmea_gettime(
+    struct timespec* ts,
+    const struct minmea_date* date,
+    const struct minmea_time* time_) {
+    struct tm tm;
+    if(minmea_getdatetime(&tm, date, time_)) return -1;
+
+    time_t timestamp = mktime(&tm); /* See README.md if your system lacks timegm(). */
+    if(timestamp != (time_t)-1) {
+        ts->tv_sec = timestamp;
+        ts->tv_nsec = time_->microseconds * 1000;
+        return 0;
+    } else {
+        return -1;
+    }
+}
+
+/* vim: set ts=4 sw=4 et: */

gps_nmea/minmea.h

@@ -0,0 +1,295 @@
+/*
+ * Copyright © 2014 Kosma Moczek <kosma@cloudyourcar.com>
+ * This program is free software. It comes without any warranty, to the extent
+ * permitted by applicable law. You can redistribute it and/or modify it under
+ * the terms of the Do What The Fuck You Want To Public License, Version 2, as
+ * published by Sam Hocevar. See the COPYING file for more details.
+ */
+
+#ifndef MINMEA_H
+#define MINMEA_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <ctype.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <time.h>
+#include <math.h>
+#ifdef MINMEA_INCLUDE_COMPAT
+#include <minmea_compat.h>
+#endif
+
+#ifndef MINMEA_MAX_SENTENCE_LENGTH
+#define MINMEA_MAX_SENTENCE_LENGTH 80
+#endif
+
+enum minmea_sentence_id {
+    MINMEA_INVALID = -1,
+    MINMEA_UNKNOWN = 0,
+    MINMEA_SENTENCE_GBS,
+    MINMEA_SENTENCE_GGA,
+    MINMEA_SENTENCE_GLL,
+    MINMEA_SENTENCE_GSA,
+    MINMEA_SENTENCE_GST,
+    MINMEA_SENTENCE_GSV,
+    MINMEA_SENTENCE_RMC,
+    MINMEA_SENTENCE_VTG,
+    MINMEA_SENTENCE_ZDA,
+};
+
+struct minmea_float {
+    int_least32_t value;
+    int_least32_t scale;
+};
+
+struct minmea_date {
+    int day;
+    int month;
+    int year;
+};
+
+struct minmea_time {
+    int hours;
+    int minutes;
+    int seconds;
+    int microseconds;
+};
+
+struct minmea_sentence_gbs {
+    struct minmea_time time;
+    struct minmea_float err_latitude;
+    struct minmea_float err_longitude;
+    struct minmea_float err_altitude;
+    int svid;
+    struct minmea_float prob;
+    struct minmea_float bias;
+    struct minmea_float stddev;
+};
+
+struct minmea_sentence_rmc {
+    struct minmea_time time;
+    bool valid;
+    struct minmea_float latitude;
+    struct minmea_float longitude;
+    struct minmea_float speed;
+    struct minmea_float course;
+    struct minmea_date date;
+    struct minmea_float variation;
+};
+
+struct minmea_sentence_gga {
+    struct minmea_time time;
+    struct minmea_float latitude;
+    struct minmea_float longitude;
+    int fix_quality;
+    int satellites_tracked;
+    struct minmea_float hdop;
+    struct minmea_float altitude;
+    char altitude_units;
+    struct minmea_float height;
+    char height_units;
+    struct minmea_float dgps_age;
+};
+
+enum minmea_gll_status {
+    MINMEA_GLL_STATUS_DATA_VALID = 'A',
+    MINMEA_GLL_STATUS_DATA_NOT_VALID = 'V',
+};
+
+// FAA mode added to some fields in NMEA 2.3.
+enum minmea_faa_mode {
+    MINMEA_FAA_MODE_AUTONOMOUS = 'A',
+    MINMEA_FAA_MODE_DIFFERENTIAL = 'D',
+    MINMEA_FAA_MODE_ESTIMATED = 'E',
+    MINMEA_FAA_MODE_MANUAL = 'M',
+    MINMEA_FAA_MODE_SIMULATED = 'S',
+    MINMEA_FAA_MODE_NOT_VALID = 'N',
+    MINMEA_FAA_MODE_PRECISE = 'P',
+};
+
+struct minmea_sentence_gll {
+    struct minmea_float latitude;
+    struct minmea_float longitude;
+    struct minmea_time time;
+    char status;
+    char mode;
+};
+
+struct minmea_sentence_gst {
+    struct minmea_time time;
+    struct minmea_float rms_deviation;
+    struct minmea_float semi_major_deviation;
+    struct minmea_float semi_minor_deviation;
+    struct minmea_float semi_major_orientation;
+    struct minmea_float latitude_error_deviation;
+    struct minmea_float longitude_error_deviation;
+    struct minmea_float altitude_error_deviation;
+};
+
+enum minmea_gsa_mode {
+    MINMEA_GPGSA_MODE_AUTO = 'A',
+    MINMEA_GPGSA_MODE_FORCED = 'M',
+};
+
+enum minmea_gsa_fix_type {
+    MINMEA_GPGSA_FIX_NONE = 1,
+    MINMEA_GPGSA_FIX_2D = 2,
+    MINMEA_GPGSA_FIX_3D = 3,
+};
+
+struct minmea_sentence_gsa {
+    char mode;
+    int fix_type;
+    int sats[12];
+    struct minmea_float pdop;
+    struct minmea_float hdop;
+    struct minmea_float vdop;
+};
+
+struct minmea_sat_info {
+    int nr;
+    int elevation;
+    int azimuth;
+    int snr;
+};
+
+struct minmea_sentence_gsv {
+    int total_msgs;
+    int msg_nr;
+    int total_sats;
+    struct minmea_sat_info sats[4];
+};
+
+struct minmea_sentence_vtg {
+    struct minmea_float true_track_degrees;
+    struct minmea_float magnetic_track_degrees;
+    struct minmea_float speed_knots;
+    struct minmea_float speed_kph;
+    enum minmea_faa_mode faa_mode;
+};
+
+struct minmea_sentence_zda {
+    struct minmea_time time;
+    struct minmea_date date;
+    int hour_offset;
+    int minute_offset;
+};
+
+/**
+ * Calculate raw sentence checksum. Does not check sentence integrity.
+ */
+uint8_t minmea_checksum(const char* sentence);
+
+/**
+ * Check sentence validity and checksum. Returns true for valid sentences.
+ */
+bool minmea_check(const char* sentence, bool strict);
+
+/**
+ * Determine talker identifier.
+ */
+bool minmea_talker_id(char talker[3], const char* sentence);
+
+/**
+ * Determine sentence identifier.
+ */
+enum minmea_sentence_id minmea_sentence_id(const char* sentence, bool strict);
+
+/**
+ * Scanf-like processor for NMEA sentences. Supports the following formats:
+ * c - single character (char *)
+ * d - direction, returned as 1/-1, default 0 (int *)
+ * f - fractional, returned as value + scale (struct minmea_float *)
+ * i - decimal, default zero (int *)
+ * s - string (char *)
+ * t - talker identifier and type (char *)
+ * D - date (struct minmea_date *)
+ * T - time stamp (struct minmea_time *)
+ * _ - ignore this field
+ * ; - following fields are optional
+ * Returns true on success. See library source code for details.
+ */
+bool minmea_scan(const char* sentence, const char* format, ...);
+
+/*
+ * Parse a specific type of sentence. Return true on success.
+ */
+bool minmea_parse_gbs(struct minmea_sentence_gbs* frame, const char* sentence);
+bool minmea_parse_rmc(struct minmea_sentence_rmc* frame, const char* sentence);
+bool minmea_parse_gga(struct minmea_sentence_gga* frame, const char* sentence);
+bool minmea_parse_gsa(struct minmea_sentence_gsa* frame, const char* sentence);
+bool minmea_parse_gll(struct minmea_sentence_gll* frame, const char* sentence);
+bool minmea_parse_gst(struct minmea_sentence_gst* frame, const char* sentence);
+bool minmea_parse_gsv(struct minmea_sentence_gsv* frame, const char* sentence);
+bool minmea_parse_vtg(struct minmea_sentence_vtg* frame, const char* sentence);
+bool minmea_parse_zda(struct minmea_sentence_zda* frame, const char* sentence);
+
+/**
+ * Convert GPS UTC date/time representation to a UNIX calendar time.
+ */
+int minmea_getdatetime(
+    struct tm* tm,
+    const struct minmea_date* date,
+    const struct minmea_time* time_);
+
+/**
+ * Convert GPS UTC date/time representation to a UNIX timestamp.
+ */
+int minmea_gettime(
+    struct timespec* ts,
+    const struct minmea_date* date,
+    const struct minmea_time* time_);
+
+/**
+ * Rescale a fixed-point value to a different scale. Rounds towards zero.
+ */
+static inline int_least32_t minmea_rescale(const struct minmea_float* f, int_least32_t new_scale) {
+    if(f->scale == 0) return 0;
+    if(f->scale == new_scale) return f->value;
+    if(f->scale > new_scale)
+        return (f->value + ((f->value > 0) - (f->value < 0)) * f->scale / new_scale / 2) /
+               (f->scale / new_scale);
+    else
+        return f->value * (new_scale / f->scale);
+}
+
+/**
+ * Convert a fixed-point value to a floating-point value.
+ * Returns NaN for "unknown" values.
+ */
+static inline float minmea_tofloat(const struct minmea_float* f) {
+    if(f->scale == 0) return NAN;
+    return (float)f->value / (float)f->scale;
+}
+
+/**
+ * Convert a raw coordinate to a floating point DD.DDD... value.
+ * Returns NaN for "unknown" values.
+ */
+static inline float minmea_tocoord(const struct minmea_float* f) {
+    if(f->scale == 0) return NAN;
+    if(f->scale > (INT_LEAST32_MAX / 100)) return NAN;
+    if(f->scale < (INT_LEAST32_MIN / 100)) return NAN;
+    int_least32_t degrees = f->value / (f->scale * 100);
+    int_least32_t minutes = f->value % (f->scale * 100);
+    return (float)degrees + (float)minutes / (60 * f->scale);
+}
+
+/**
+ * Check whether a character belongs to the set of characters allowed in a
+ * sentence data field.
+ */
+static inline bool minmea_isfield(char c) {
+    return isprint((unsigned char)c) && c != ',' && c != '*';
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* MINMEA_H */
+
+/* vim: set ts=4 sw=4 et: */