main.c File Reference

Application entry point for the GPS tracking device. More...

#include <stdbool.h>
#include <stdint.h>
#include <string.h>
#include "arm_cortex_m4_systick.h"
#include "button.h"
#include "common.h"
#include "err.h"
#include "io.h"
#include "neo6.h"
#include "menu.h"
#include "stm32f401re.h"
#include "stm32f401re_gpio.h"
#include "console.h"
#include "ssd1309.h"
#include "datalog.h"

Include dependency graph for main.c:

Go to the source code of this file.

Functions
static void	init_all (void)
	Initializes all subsystems and hardware peripherals.
static void	run_all (void)
	Runs all subsystems for one iteration of the main loop.
static ERR_te	acquire_neo6_location (uint8_t index, char **value_o)
	Data-view callback for the location menu.
static ERR_te	acquire_datetime (uint8_t index, char **value_o)
	Data-view callback for the date/time menu.
static ERR_te	acquire_movement (uint8_t index, char **value_o)
	Data-view callback for the movement menu.
static ERR_te	acquire_accuracy (uint8_t index, char **value_o)
	Data-view callback for the accuracy menu.
static ERR_te	acquire_satellites (uint8_t index, char **value_o)
	Data-view callback for the satellites menu.
int	main (void)

Variables
SSD1309_HANDLE_ts *	ssd1309_handle
BUTTON_HANDLE_ts *	lbtn
BUTTON_HANDLE_ts *	mbtn
BUTTON_HANDLE_ts *	rbtn
MENU_HANDLE_ts *	current_menu
MENU_HANDLE_ts *	main_menu
MENU_HANDLE_ts *	location_menu
MENU_HANDLE_ts *	datetime_menu
MENU_HANDLE_ts *	movement_menu
MENU_HANDLE_ts *	accuracy_menu
MENU_HANDLE_ts *	satellites_menu
NEO6_HANDLE_ts *	neo6_handle
DATALOG_HANDLE_ts *	datalog_handle
bool	lbtn_pushed = false
bool	mbtn_pushed = false
bool	rbtn_pushed = false
bool	can_toggle_lbtn = true
bool	can_toggle_mbtn = true
bool	can_toggle_rbtn = true
bool	mbtn_held = false
bool	can_hold_mbtn = true
bool	refresh = true
char	selected_option [SSD1309_MAX_CHARS_IN_LINE]
uint32_t	refreshed_ms

Detailed Description

Application entry point for the GPS tracking device.

Author

github.com/Baksi675

This file contains the top-level application logic for a GPS tracking device built on the STM32F401RE microcontroller. It ties together all subsystems and drives the main loop.

The device provides:

• Real-time GPS data display on an SSD1309 OLED via a scrollable menu system
• Three-button navigation (left scroll, middle select/back-hold, right scroll)
• Periodic GPS data logging to SD card via the datalog module
• A USART console for runtime command dispatch and log level control

Subsystem initialization order in init_all:

1. IO (test LED)
2. Console (USART1, log dependency initialized internally)
3. SSD1309 OLED display
4. Buttons (left, middle, right)
5. NEO-6 GPS module
6. Menu system (main, location, date/time, movement, accuracy, satellites)
7. Datalog (SD card, 10-second interval)

Attention

On the prototype hardware, the FatFs diskio.c CS pin must be configured as GPIOB pin 6.

Version

0.1

Date

2026-01-01

Copyright

Copyright (c) 2026

Definition in file main.c.

Function Documentation

init_all()

void init_all ( void )

static

Initializes all subsystems and hardware peripherals.

Called once at startup. Configures every subsystem in dependency order and sets current_menu to the top-level main menu. See the main.c file description for the full initialization sequence.

Definition at line 117 of file main.c.

                           {
    GPIO_CFG_ts test_led = { 0 };
    test_led.mode = GPIO_MODE_OUTPUT;
    test_led.pin = GPIO_PIN_15;
    test_led.port = GPIOB;
    gpio_init(&test_led);
    IO_CFG_ts io_test_led_conf = { 0 };
    IO_HANDLE_ts *io_test_led_handle = { 0 };
    io_test_led_conf.gpio_handle = &test_led;
    str_cpy(io_test_led_conf.name, "test_led", get_str_len("test_led") + 1);
    io_init_subsys();
    io_init_handle(&io_test_led_conf, &io_test_led_handle);
    io_start_subsys();
 
    CONSOLE_HANDLE_ts console_handle = { 0 };
    console_handle.usart_instance = USART1;
    console_handle.usart_baud_rate = USART_BAUD_RATE_115200;
    console_handle.gpio_port = GPIOA;
    console_handle.gpio_pin = GPIO_PIN_10;
    console_handle.gpio_alternate_function = GPIO_ALTERNATE_FUNCTION_AF7;
    console_init(&console_handle);
 
    SSD1309_CFG_ts ssd1309_conf = { 0 };
    ssd1309_get_def_cfg(&ssd1309_conf);
    ssd1309_conf.i2c_instance = I2C1;
    ssd1309_conf.gpio_alternate_function = GPIO_ALTERNATE_FUNCTION_AF4;
    ssd1309_conf.scl_gpio_pin = GPIO_PIN_8;
    ssd1309_conf.scl_gpio_port = GPIOB;
    ssd1309_conf.sda_gpio_pin = GPIO_PIN_9;
    ssd1309_conf.sda_gpio_port = GPIOB;
    ssd1309_init_subsys();
    ssd1309_init_handle(&ssd1309_conf, &ssd1309_handle);
    ssd1309_start_subsys();
 
    BUTTON_CFG_ts lbtn_cfg = { 0 };
    lbtn_cfg.gpio_port = GPIOB;
    lbtn_cfg.gpio_pin = GPIO_PIN_5;
    lbtn_cfg.debounce_limit_ms = 50;
    lbtn_cfg.held_limit_ms = 1000;
    lbtn_cfg.pushed_type = BUTTON_PUSHED_TYPE_HIGH;
    str_cpy(lbtn_cfg.name, "leftbtn", get_str_len("leftbtn") + 1);
 
    BUTTON_CFG_ts mbtn_cfg = { 0 };
    mbtn_cfg.gpio_port = GPIOB;
    mbtn_cfg.gpio_pin = GPIO_PIN_4;
    mbtn_cfg.debounce_limit_ms = 50;
    mbtn_cfg.held_limit_ms = 1000;
    mbtn_cfg.pushed_type = BUTTON_PUSHED_TYPE_HIGH;
    str_cpy(mbtn_cfg.name, "midbtn", get_str_len("midbtn") + 1);
 
    BUTTON_CFG_ts rbtn_cfg = { 0 };
    rbtn_cfg.gpio_port = GPIOB;
    rbtn_cfg.gpio_pin = GPIO_PIN_10;
    rbtn_cfg.debounce_limit_ms = 50;
    rbtn_cfg.held_limit_ms = 1000;
    rbtn_cfg.pushed_type = BUTTON_PUSHED_TYPE_HIGH;
    str_cpy(rbtn_cfg.name, "rightbtn", get_str_len("rightbtn") + 1);
 
    button_init_subsys();
    button_init_handle(&lbtn_cfg, &lbtn);
    button_init_handle(&mbtn_cfg, &mbtn);
    button_init_handle(&rbtn_cfg, &rbtn);
    button_start_subsys();
 
    NEO6_CFG_ts neo6_cfg = { 0 };
    neo6_cfg.usart_instance = USART6;
    neo6_cfg.usart_baud_rate = 9600;
    neo6_cfg.rx_gpio_port = GPIOA;
    neo6_cfg.rx_gpio_pin = GPIO_PIN_12;
    neo6_cfg.tx_gpio_port = GPIOA;
    neo6_cfg.tx_gpio_pin = GPIO_PIN_11;
    neo6_cfg.gpio_alternate_function = GPIO_ALTERNATE_FUNCTION_AF8;
    neo6_init_subsys();
    neo6_init_handle(&neo6_cfg, &neo6_handle);
    neo6_start_subsys();
 
    MENU_CFG_ts main_menu_cfg = { 0 };
    txt_cpy(main_menu_cfg.name, "main", get_str_len("main"));
    txt_cpy(main_menu_cfg.title, "      MENU      ", 16);
    txt_cpy(main_menu_cfg.options[0], "LOCATION", get_str_len("LOCATION"));
    txt_cpy(main_menu_cfg.options[1], "DATE/TIME", get_str_len("DATE/TIME"));
    txt_cpy(main_menu_cfg.options[2], "MOVEMENT", get_str_len("MOVEMENT"));
    txt_cpy(main_menu_cfg.options[3], "ACCURACY", get_str_len("ACCURACY"));
    txt_cpy(main_menu_cfg.options[4], "SATELLITES", get_str_len("SATELLITES"));
    main_menu_cfg.type = MENU_TYPE_SELECTABLE;
 
    MENU_CFG_ts location_menu_cfg = { 0 };
    txt_cpy(location_menu_cfg.name, "loc", get_str_len("loc"));
    txt_cpy(location_menu_cfg.title, "    LOCATION    ", 16);
    txt_cpy(location_menu_cfg.options[0], "Latitude:", get_str_len("Latitude:"));
    txt_cpy(location_menu_cfg.options[1], "Longitude:", get_str_len("Longitude:"));
    txt_cpy(location_menu_cfg.options[2], "Orthometric h.:", get_str_len("Orthometric h.:"));
    txt_cpy(location_menu_cfg.options[3], "Geoid sep.:", get_str_len("Geoid sep.:"));
    location_menu_cfg.type = MENU_TYPE_DATA_VIEW;
    location_menu_cfg.get_value_fn = acquire_neo6_location;
 
    MENU_CFG_ts datetime_menu_cfg = { 0 };
    txt_cpy(datetime_menu_cfg.name, "dt", get_str_len("dt"));
    txt_cpy(datetime_menu_cfg.title, "   DATE/TIME    ", 16);
    txt_cpy(datetime_menu_cfg.options[0], "Current date:", get_str_len("Current date:"));
    txt_cpy(datetime_menu_cfg.options[1], "Current time:", get_str_len("Current time:"));
    datetime_menu_cfg.type = MENU_TYPE_DATA_VIEW;
    datetime_menu_cfg.get_value_fn = acquire_datetime;
 
    MENU_CFG_ts movement_menu_cfg = { 0 };
    txt_cpy(movement_menu_cfg.name, "mov", get_str_len("mov"));
    txt_cpy(movement_menu_cfg.title, "    MOVEMENT    ", 16);
    txt_cpy(movement_menu_cfg.options[0], "Movement speed:", get_str_len("Movement speed:"));
    txt_cpy(movement_menu_cfg.options[1], "Movement dir.:", get_str_len("Movement dir.:"));
    movement_menu_cfg.type = MENU_TYPE_DATA_VIEW;
    movement_menu_cfg.get_value_fn = acquire_movement;
 
    MENU_CFG_ts accuracy_menu_cfg = { 0 };
    txt_cpy(accuracy_menu_cfg.name, "acc", get_str_len("acc"));
    txt_cpy(accuracy_menu_cfg.title, "    ACCURACY    ", 16);
    txt_cpy(accuracy_menu_cfg.options[0], "Fix status:", get_str_len("Fix status:"));
    txt_cpy(accuracy_menu_cfg.options[1], "Fix type:", get_str_len("Fix type:"));
    txt_cpy(accuracy_menu_cfg.options[2], "PDOP:", get_str_len("PDOP:"));
    txt_cpy(accuracy_menu_cfg.options[3], "HDOP:", get_str_len("HDOP:"));
    txt_cpy(accuracy_menu_cfg.options[4], "VDOP:", get_str_len("VDOP:"));
    accuracy_menu_cfg.type = MENU_TYPE_DATA_VIEW;
    accuracy_menu_cfg.get_value_fn = acquire_accuracy;
 
    MENU_CFG_ts satellites_menu_cfg = { 0 };
    txt_cpy(satellites_menu_cfg.name, "sats", get_str_len("sats"));
    txt_cpy(satellites_menu_cfg.title, "   SATELLITES   ", 16);
    txt_cpy(satellites_menu_cfg.options[0], "Num sats:", get_str_len("Num sats:"));
    txt_cpy(satellites_menu_cfg.options[1], "Num sats used:", get_str_len("Num sats used:"));
    satellites_menu_cfg.type = MENU_TYPE_DATA_VIEW;
    satellites_menu_cfg.get_value_fn = acquire_satellites;
 
    menu_init_subsys();
    menu_init_handle(&main_menu_cfg, &main_menu);
    menu_init_handle(&location_menu_cfg, &location_menu);
    menu_init_handle(&datetime_menu_cfg, &datetime_menu);
    menu_init_handle(&movement_menu_cfg, &movement_menu);
    menu_init_handle(&accuracy_menu_cfg, &accuracy_menu);
    menu_init_handle(&satellites_menu_cfg, &satellites_menu);
    menu_start_subsys();
 
    current_menu = main_menu;
 
    DATALOG_CFG_ts datalog_cfg = { 0 };
    str_cpy(datalog_cfg.name, "datalog", get_str_len("datalog") + 1);
    datalog_cfg.datalog_time = DATALOG_TIME_10S;
    datalog_init_subsys();
    datalog_init_handle(&datalog_cfg, &datalog_handle);
    datalog_start_subsys();
}

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run_all()

void run_all ( void )

static

Runs all subsystems for one iteration of the main loop.

Called on every iteration of the superloop in main. Performs the following steps in order:

1. Updates the NEO-6 GPS parser.
2. Processes any pending console input and dispatches commands.
3. Appends a GPS log entry if the datalog interval has elapsed.
4. Debounces and samples all three buttons.
5. Handles button events:
   • Left button: scroll down.
   • Right button: scroll up.
   • Middle button press: navigate into the selected submenu.
   • Middle button hold: navigate back to the previous menu.
6. Forces a display refresh every 1000 ms regardless of button activity.
7. Redraws current_menu if refresh is set.

Note

Button events use an edge-detect pattern (can_toggle / can_hold flags) to prevent repeated triggering while a button remains held.

Definition at line 288 of file main.c.

                          {
    neo6_run();
 
    console_run();
 
    datalog_run_handle(datalog_handle);
 
    button_run_handle_all();
 
    button_get_pushed_state(lbtn, &lbtn_pushed);
    button_get_pushed_state(mbtn, &mbtn_pushed);
    button_get_pushed_state(rbtn, &rbtn_pushed);
 
    button_get_held_state(mbtn, &mbtn_held);
 
    if(lbtn_pushed && can_toggle_lbtn) {
        menu_scroll(current_menu, DOWN);
 
        refresh = true;
        can_toggle_lbtn = false;
    }
    else if(!lbtn_pushed && !can_toggle_lbtn) {
        can_toggle_lbtn = true;
    }
 
    if(mbtn_pushed && can_toggle_mbtn) {
        menu_get_selected_option(current_menu, selected_option);
 
        if(current_menu == main_menu) {
            if(str_cmp(selected_option, "LOCATION") == true) {
                menu_set_prev_menu(location_menu, current_menu);
                current_menu = location_menu;
                refresh = true;
            }
            else if(str_cmp(selected_option, "DATE/TIME") == true) {
                menu_set_prev_menu(datetime_menu, current_menu);
                current_menu = datetime_menu;
                refresh = true;
            }
            else if(str_cmp(selected_option, "MOVEMENT") == true) {
                menu_set_prev_menu(movement_menu, current_menu);
                current_menu = movement_menu;
                refresh = true;
            }
            else if(str_cmp(selected_option, "ACCURACY") == true) {
                menu_set_prev_menu(accuracy_menu, current_menu);
                current_menu = accuracy_menu;
                refresh = true;
            }
            else if(str_cmp(selected_option, "SATELLITES") == true) {
                menu_set_prev_menu(satellites_menu, current_menu);
                current_menu = satellites_menu;
                refresh = true;
            }
        }
 
        can_toggle_mbtn = false;
    }
    else if(!mbtn_pushed && !can_toggle_mbtn) {
        can_toggle_mbtn = true;
    }
 
    if(mbtn_held && can_hold_mbtn) {
        MENU_HANDLE_ts *prev_menu = { 0 };
 
        menu_get_prev_menu(current_menu, &prev_menu);
        current_menu = prev_menu;
        refresh = true;
 
        can_hold_mbtn = false;
    }
    else if(!mbtn_held && !can_hold_mbtn) {
        can_hold_mbtn = true;
    }
 
    if(rbtn_pushed && can_toggle_rbtn) {
        menu_scroll(current_menu, UP);
 
        refresh = true;
        can_toggle_rbtn = false;
    }
    else if(!rbtn_pushed && !can_toggle_rbtn) {
        can_toggle_rbtn = true;
    }
 
    if(systick_get_ms() - refreshed_ms >= 1000) {
        refresh = true;
    }
 
    if(refresh) {
        menu_run_handle(current_menu);
        refresh = false;
        refreshed_ms = systick_get_ms();
    }
}

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acquire_neo6_location()

ERR_te acquire_neo6_location ( uint8_t index, char ** value_o )

static

Data-view callback for the location menu.

Returns GPS location fields from the NEO-6 info structure: index 0 = latitude, 1 = longitude, 2 = orthometric height, 3 = geoid separation.

Definition at line 391 of file main.c.

                                                                   {
    NEO6_INFO_ts *neo6_info = NULL;
    neo6_get_info(&neo6_info);
 
    switch(index) {
        case 0: *value_o = neo6_info->lat;        break;
        case 1: *value_o = neo6_info->lon;        break;
        case 2: *value_o = neo6_info->ort_height; break;
        case 3: *value_o = neo6_info->geoid_sep;  break;
    }
 
    return ERR_OK;
}

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acquire_datetime()

ERR_te acquire_datetime ( uint8_t index, char ** value_o )

static

Data-view callback for the date/time menu.

Returns GPS date/time fields from the NEO-6 info structure: index 0 = date, 1 = time.

Definition at line 412 of file main.c.

                                                              {
    NEO6_INFO_ts *neo6_info = NULL;
    neo6_get_info(&neo6_info);
 
    switch(index) {
        case 0: *value_o = neo6_info->date; break;
        case 1: *value_o = neo6_info->time; break;
    }
 
    return ERR_OK;
}

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acquire_movement()

ERR_te acquire_movement ( uint8_t index, char ** value_o )

static

Data-view callback for the movement menu.

Returns movement fields from the NEO-6 info structure: index 0 = movement speed, 1 = movement direction.

Definition at line 431 of file main.c.

                                                              {
    NEO6_INFO_ts *neo6_info = NULL;
    neo6_get_info(&neo6_info);
 
    switch(index) {
        case 0: *value_o = neo6_info->mov_speed; break;
        case 1: *value_o = neo6_info->mov_dir;   break;
    }
 
    return ERR_OK;
}

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acquire_accuracy()

ERR_te acquire_accuracy ( uint8_t index, char ** value_o )

static

Data-view callback for the accuracy menu.

Returns fix quality fields from the NEO-6 info structure: index 0 = fix status, 1 = fix type, 2 = PDOP, 3 = HDOP, 4 = VDOP.

Definition at line 450 of file main.c.

                                                              {
    NEO6_INFO_ts *neo6_info = NULL;
    neo6_get_info(&neo6_info);
 
    switch(index) {
        case 0: *value_o = neo6_info->fix_status; break;
        case 1: *value_o = neo6_info->fix_type;   break;
        case 2: *value_o = neo6_info->pdop;       break;
        case 3: *value_o = neo6_info->hdop;       break;
        case 4: *value_o = neo6_info->vdop;       break;
    }
 
    return ERR_OK;
}

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acquire_satellites()

ERR_te acquire_satellites ( uint8_t index, char ** value_o )

static

Data-view callback for the satellites menu.

Returns satellite count fields from the NEO-6 info structure: index 0 = total satellites in view, 1 = satellites used in fix.

Definition at line 472 of file main.c.

                                                                {
    NEO6_INFO_ts *neo6_info = NULL;
    neo6_get_info(&neo6_info);
 
    switch(index) {
        case 0: *value_o = neo6_info->num_sats_all;  break;
        case 1: *value_o = neo6_info->num_sats_used; break;
    }
 
    return ERR_OK;
}

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main()

int main

(

void

)

Definition at line 96 of file main.c.

               {
    init_all();
 
    // Delay here is needed to not crash the system
    DELAY(50);
 
    while(1) {
        run_all();
    }
 
    return 0;
}

Variable Documentation

ssd1309_handle

SSD1309_HANDLE_ts* ssd1309_handle

OLED display handle.

Definition at line 54 of file main.c.

lbtn

BUTTON_HANDLE_ts* lbtn

Left button handle.

Definition at line 55 of file main.c.

mbtn

BUTTON_HANDLE_ts* mbtn

Middle button handle (select / back-hold).

Definition at line 56 of file main.c.

rbtn

BUTTON_HANDLE_ts* rbtn

Right button handle.

Definition at line 57 of file main.c.

current_menu

MENU_HANDLE_ts* current_menu

Pointer to the menu currently displayed.

Definition at line 58 of file main.c.

main_menu

MENU_HANDLE_ts* main_menu

Top-level selectable menu.

Definition at line 59 of file main.c.

location_menu

MENU_HANDLE_ts* location_menu

Data-view menu: latitude, longitude, height, geoid.

Definition at line 60 of file main.c.

datetime_menu

MENU_HANDLE_ts* datetime_menu

Data-view menu: GPS date and time.

Definition at line 61 of file main.c.

movement_menu

MENU_HANDLE_ts* movement_menu

Data-view menu: speed and direction.

Definition at line 62 of file main.c.

accuracy_menu

MENU_HANDLE_ts* accuracy_menu

Data-view menu: fix status, fix type, DOP values.

Definition at line 63 of file main.c.

satellites_menu

MENU_HANDLE_ts* satellites_menu

Data-view menu: satellite counts.

Definition at line 64 of file main.c.

neo6_handle

NEO6_HANDLE_ts* neo6_handle

NEO-6 GPS module handle.

Definition at line 65 of file main.c.

datalog_handle

DATALOG_HANDLE_ts* datalog_handle

SD card data log handle.

Definition at line 66 of file main.c.

lbtn_pushed

bool lbtn_pushed = false

True while the left button is held down.

Definition at line 78 of file main.c.

mbtn_pushed

bool mbtn_pushed = false

True while the middle button is held down.

Definition at line 79 of file main.c.

rbtn_pushed

bool rbtn_pushed = false

True while the right button is held down.

Definition at line 80 of file main.c.

can_toggle_lbtn

bool can_toggle_lbtn = true

Edge-detect guard for the left button.

Definition at line 81 of file main.c.

can_toggle_mbtn

bool can_toggle_mbtn = true

Edge-detect guard for the middle button.

Definition at line 82 of file main.c.

can_toggle_rbtn

bool can_toggle_rbtn = true

Edge-detect guard for the right button.

Definition at line 83 of file main.c.

mbtn_held

bool mbtn_held = false

True when the middle button has been held long enough.

Definition at line 84 of file main.c.

can_hold_mbtn

bool can_hold_mbtn = true

Edge-detect guard for the middle button hold.

Definition at line 85 of file main.c.

refresh

bool refresh = true

True when the display should be redrawn on the next iteration.

Definition at line 88 of file main.c.

selected_option

char selected_option[SSD1309_MAX_CHARS_IN_LINE]

Buffer for the option string returned by menu_get_selected_option.

Definition at line 91 of file main.c.

refreshed_ms

uint32_t refreshed_ms

Systick timestamp (ms) of the most recent display refresh.

Definition at line 94 of file main.c.