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/****************************************************************************

 *   Copyright (C) 2009 by Claas Anders "CaScAdE" Rathje                    *

 *   admiralcascade@gmail.com                                               *

 *   Project-URL: http://www.mylifesucks.de/oss/c-osd/                      *

 *                                                                          *

 *   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 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.              *

 *                                                                          *

 *                                                                          *

 *   Credits to:                                                            *

 *   Holger Buss & Ingo Busker from mikrokopter.de for the MK project       *

 *   Gregor "killagreg" Stobrawa for making the MK code readable            *

 *   Klaus "akku" Buettner for the hardware                                 *

 *   Manuel "KeyOz" Schrape for explaining the MK protocol to me            *

 ****************************************************************************/

#include <avr/io.h>

#include <avr/interrupt.h>

#include <util/delay.h>

#include <avr/pgmspace.h>

#include "main.h"

#include "max7456_software_spi.h"

#include "usart1.h"

#include "osd_helpers.h"

/* TODO:

 * - verifiy correctness of values

 * - clean up code :)

 */

#if !(ALLCHARSDEBUG|(WRITECHARS != -1))

// data structs not needed for character flashin

#include "mk-data-structs.h"

/* ##########################################################################

 * global definitions and global vars

 * ##########################################################################*/

volatile uint16_t setsReceived = 0;

volatile NaviData_t naviData;

volatile DebugOut_t debugData;

// cache old vars for blinking attribute, checkup is faster than full

// attribute write each time

volatile uint8_t last_UBat = 255;

volatile uint8_t last_RC_Quality = 255;

// 16bit should be enough, normal LiPos don't last that long

volatile uint16_t uptime = 0;

volatile uint16_t timer = 0;

// remember last time data was received

volatile uint8_t seconds_since_last_data = 0;

// store stats description in progmem to save space

char stats_item_0[] PROGMEM = "max Altitude:";

char stats_item_1[] PROGMEM = "max Speed   :";

char stats_item_2[] PROGMEM = "max Distance:";

char stats_item_3[] PROGMEM = "min voltage :";

char stats_item_4[] PROGMEM = "max time    :";

char stats_item_5[] PROGMEM = "longitude   :";

char stats_item_6[] PROGMEM = "latitude    :";

char* stats_item_pointers[] PROGMEM = {stats_item_0, stats_item_1, stats_item_2,

    stats_item_3, stats_item_4, stats_item_5, stats_item_6};

// store more fixed strings in progmen

char ON[] PROGMEM = "ON ";

char OFF[] PROGMEM = "OFF";

#endif // ends !(ALLCHARSDEBUG|(WRITECHARS != -1))

// general PAL|NTSC distingiusch stuff

uint8_t top_line = 1;

uint8_t bottom_line = 14;

// battery voltages

uint8_t min_voltage = 0;

uint8_t max_voltage = 0;

// Flags

uint8_t COSD_FLAGS = 0;

/* ##########################################################################

 * debounce buttons

 * ##########################################################################*/

int s1_pressed() {

    if (S1_PRESSED) {

        _delay_ms(25);

        if (S1_PRESSED) return 1;

    }

    return 0;

}

int s2_pressed() {

    if (S2_PRESSED) {

        _delay_ms(25);

        if (S2_PRESSED) return 1;

    }

    return 0;

}

/* ##########################################################################

 * Interrupt handler

 * ##########################################################################*/

/**

 * handler for undefined Interrupts

 * if not defined AVR will reset in case any unhandled interrupts occur

 */

ISR(__vector_default) {

    asm("nop");

}

#if !(ALLCHARSDEBUG|(WRITECHARS != -1))

/* ##########################################################################

 * timer stuff

 * ##########################################################################*/

/**

 * timer kicks in every 1000uS ^= 1ms

 */

ISR(TIMER0_OVF_vect) {

    OCR0 = 15; // preload

    if (!timer--) {

        uptime++;

        timer = 999;

        seconds_since_last_data++;

    }

}

/* ##########################################################################

 * A simple config menu for the flags

 * ##########################################################################*/

/**

 * helper function for menu updating

 */

void config_menu_drawings(uint8_t chosen) {

    // clear prevoius _cursor_

    write_ascii_string(3, (chosen + 5) % 8, " ");

    // draw current _cursor_

    write_ascii_string(3, chosen + 5, ">");

    if (COSD_FLAGS & COSD_FLAG_HUD) {

        write_ascii_string_pgm(23, 5, ON);

    } else {

        write_ascii_string_pgm(23, 5, OFF);

    }

    if (COSD_FLAGS & COSD_FLAG_ARTHORIZON) {

        write_ascii_string_pgm(23, 6, ON);

    } else {

        write_ascii_string_pgm(23, 6, OFF);

    }

    if (COSD_FLAGS & COSD_FLAG_BIGVARIO) {

        write_ascii_string_pgm(23, 7, ON);

    } else {

        write_ascii_string_pgm(23, 7, OFF);

    }

    if (COSD_FLAGS & COSD_FLAG_STATS) {

        write_ascii_string_pgm(23, 8, ON);

    } else {

        write_ascii_string_pgm(23, 8, OFF);

    }

    if (COSD_FLAGS & COSD_FLAG_WARNINGS) {

        write_ascii_string_pgm(23, 9, ON);

    } else {

        write_ascii_string_pgm(23, 9, OFF);

    }

}

/**

 * some sort of clicking response in the menu

 */

void config_menu_doclick(uint8_t chosen, char** menu) {

    write_ascii_string(4, chosen + 5, "DONE              ");

    _delay_ms(1000);

    write_ascii_string(4, chosen + 5, menu[chosen]);

}

/**

 * a simple config menu tryout

 */

void config_menu(void) {

    // disable interrupts (makes the menu more smoothely)

    cli();

    // clear screen

    clear();

    char* menu[9] = {"Full HUD",

        "Art.Horizon in HUD",

        "Big Vario bar",

        "Statistics",

        "Warnings", // TODO: do it!

        "Reset uptime",

        "Request OSD-data",

        "Disable Debug-data",

        "EXIT"};

    uint8_t inmenu = 1;

    uint8_t chosen = 0;

    write_ascii_string(6, 2, "C-OSD Config Menu");

    // wait a bit before doing stuff so user has chance to release button

    _delay_ms(250);

    write_ascii_string(4, 5, menu[0]);

    write_ascii_string(4, 6, menu[1]);

    write_ascii_string(4, 7, menu[2]);

    write_ascii_string(4, 8, menu[3]);

    write_ascii_string(4, 9, menu[4]);

    write_ascii_string(4, 10, menu[5]);

    write_ascii_string(4, 11, menu[6]);

    write_ascii_string(4, 12, menu[7]);

    write_ascii_string(4, 13, menu[8]);

    config_menu_drawings(chosen);

    while (inmenu) {

        if (s2_pressed()) {

            write_ascii_string(3, chosen + 5, " ");

            chosen = (chosen + 1) % 9;

            write_ascii_string(3, chosen + 5, ">");

            _delay_ms(500);

        } else if (s1_pressed()) {

            switch (chosen) {

                case 0: // full HUD

                    COSD_FLAGS ^= COSD_FLAG_HUD;

                    config_menu_drawings(chosen);

                    break;

                case 1: // art horizon

                    COSD_FLAGS ^= COSD_FLAG_ARTHORIZON;

                    config_menu_drawings(chosen);

                    break;

                case 2: // big vario

                    COSD_FLAGS ^= COSD_FLAG_BIGVARIO;

                    config_menu_drawings(chosen);

                    break;

                case 3: // statistics

                    COSD_FLAGS ^= COSD_FLAG_STATS;

                    config_menu_drawings(chosen);

                    break;

                case 4: // warnings

                    COSD_FLAGS ^= COSD_FLAG_WARNINGS;

                    config_menu_drawings(chosen);

                    break;

                case 5: // reset uptime

                    uptime = 0;

                    config_menu_doclick(chosen, menu);

                    break;

                case 6: // re-request OSD data

#if FCONLY

                    // request data ever 100ms from FC;

                    usart1_request_mk_data(0, 'd', 100);

#else

                    // request OSD Data from NC every 100ms

                    usart1_request_mk_data(1, 'o', 100);

                    // and disable debug...

                    usart1_request_mk_data(0, 'd', 0);

#endif

                    config_menu_doclick(chosen, menu);

                    break;

                case 7: // disable debug data

                    // disable sending of debug data

                    // may result in smoother ddata display

                    usart1_request_mk_data(0, 'd', 0);

                    config_menu_doclick(chosen, menu);

                    break;

                case 8: // exit

                    inmenu = 0;

                    break;

            }

            _delay_ms(250);

        }

    }

    // clear screen up again

    clear();

    // update flags to paint display again if needed

    COSD_FLAGS &= ~COSD_ICONS_WRITTEN;

    // enable interrupts again

    sei();

}

/**

 * auto config some stuff on startup, currently only battery cells

 * TODO: this is testing stuff, strings should go progmem and so on...

 */

void auto_config(uint8_t UBat, uint8_t* min_UBat) {

    clear();

    // fix for min_bat glitch caused by data only gathered during motors up

    *min_UBat = UBat;

    write_ascii_string(2, 2, "C-OSD Initialisation");

#if FCONLY

    write_ascii_string(2, 3, "FC only Mode");

#else

    write_ascii_string(2, 3, "NaviCtrl Mode");

#endif

    uint8_t cellnum = 0;

    if (CELL_NUM == -1) {

        write_ascii_string(2, 5, "Guessing Number of Cells");

        do {

            cellnum++;

        } while (UBat > ((cellnum * CELL_VOLT_MAX) + 10));

    } else {

        cellnum = CELL_NUM;

    }

    min_voltage = cellnum * CELL_VOLT_MIN;

    max_voltage = cellnum * CELL_VOLT_MAX;

    write_ascii_string(2, 7, "Number of Cells:");

    write_ndigit_number_u(21, 7, cellnum, 1, 0);

    write_ascii_string(2, 8, "Warn Voltage   :");

    write_ndigit_number_s_10th(20, 8, min_voltage, 100, 0);

    write_ascii_string(2, 9, "Max Voltage    :");

    write_ndigit_number_s_10th(20, 9, max_voltage, 100, 0);

    _delay_ms(200);

    clear();

    // update flags to paint display again because of clear

    COSD_FLAGS &= ~COSD_ICONS_WRITTEN;

}

#endif // ends !(ALLCHARSDEBUG|(WRITECHARS != -1))

/* ##########################################################################

 * MAIN

 * ##########################################################################*/

int main(void) {

    // set up FLAGS, compiler should flatten this one

    COSD_FLAGS = (NTSC << 0);

    COSD_FLAGS |= (HUD << 1);

    COSD_FLAGS |= (ARTHORIZON << 2);

    COSD_FLAGS |= (BIGVARIO << 3);

    COSD_FLAGS |= (STATS << 4);

    COSD_FLAGS |= (WARNINGS << 5);

    // set up Atmega162 Ports

    DDRA |= (1 << PA1); // PA1 output (/CS)

    MAX_CS_HIGH

    DDRA |= (1 << PA2); // PA2 output (SDIN)

    MAX_SDIN_LOW

    DDRA |= (1 << PA3); // PA3 output (SCLK)

    MAX_SCLK_LOW

    DDRA |= (1 << PA5); // PA5 output (RESET)

    MAX_RESET_HIGH

    DDRC |= (1 << PC0); // PC0 output (LED1 gn)

    LED1_OFF

    DDRC |= (1 << PC1); // PC1 output (LED2 rt)

    LED2_OFF

    DDRC |= (1 << PC2); // PC2 output (LED3 gn)

    LED3_OFF

    DDRC |= (1 << PC3); // PC3 output (LED4 rt)

    LED4_OFF

    DDRC &= ~(1 << PC4); // PC4 input  (MODE)

    PORTC |= (1 << PC4); // pullup

    DDRC &= ~(1 << PC5); // PC5 input  (SET)

    PORTC |= (1 << PC5); // pullup

    // set up top and bottom lines

    if (COSD_FLAGS & COSD_FLAG_NTSC) {

        bottom_line = 12;

    } else {

        bottom_line = 14;

    }

    // reset the MAX7456 to be sure any undefined states do no harm

    MAX_RESET_LOW

    MAX_RESET_HIGH

    // give the FC/NC and the maxim time to come up

    LED4_ON

    _delay_ms(2000);

    LED4_OFF

    //Pushing NEW chars to the MAX7456

#if (WRITECHARS != -1)

    // DISABLE display (VM0)

    spi_send_byte(0x00, 0b00000000);

    #include "characters.c"

#endif

    // Setup Video Mode

    if (COSD_FLAGS & COSD_FLAG_NTSC) {

        // NTSC + enable display immediately (VM0)

        spi_send_byte(0x00, 0b00001000);

    } else {

        // PAL + enable display immediately (VM0)

        spi_send_byte(0x00, 0b01001000);

    }

    /*// clear all display-mem (DMM)

    spi_send_byte(0x04, 0b00000100);

    // clearing takes 12uS according to maxim so lets wait longer

    _delay_us(120);

    // 8bit mode

    spi_send_byte(0x04, 0b01000000);*/

    // clear display memory and set to 8bit mode

    clear();

#if !(ALLCHARSDEBUG|(WRITECHARS != -1))

    // init usart

    usart1_init();

    // set up timer

    TCCR0 |= (1 << CS00) | (1 << CS01); // timer0 prescaler 64

    OCR0 = 15; // preload

    TIMSK |= (1 << TOIE0); // enable overflow timer0

    // enable interrupts

    sei();

#endif

    //write_ascii_string(2,  7, "         CaScAdE          ");

    //write_ascii_string(2,  8, "is TESTING his open source");

    //write_ascii_string(2,  9, "    EPi OSD Firmware");

    // we are ready

    LED3_ON

#if ALLCHARSDEBUG | (WRITECHARS != -1)

    clear();

    write_all_chars();

#else

    // clear serial screen

    //usart1_puts("\x1B[2J\x1B[H");

    //usart1_puts("hello world!\r\n");

#if FCONLY

    // request data ever 100ms from FC;

    usart1_request_mk_data(0, 'd', 100);

#else

    // request OSD Data from NC every 100ms

    usart1_request_mk_data(1, 'o', 100);

    // and disable debug...

    usart1_request_mk_data(0, 'd', 0);

#endif

    // stats for after flight

    int16_t max_Altimeter = 0;

    uint16_t max_GroundSpeed = 0;

    int16_t max_Distance = 0;

    uint8_t min_UBat = 255;

    uint16_t max_FlyingTime = 0;

    // flags from last round to check for changes

    uint8_t old_MKFlags = 0;

    char* directions[8] = {"NE", "E ", "SE", "S ", "SW", "W ", "NW", "N "};

    //char arrowdir[8] = {218, 217, 224, 223, 222, 221, 220, 219};

    while (1) {

        // write icons at init or after menu/mode-switch

        if (!(COSD_FLAGS & COSD_ICONS_WRITTEN) && (COSD_FLAGS & COSD_FLAG_HUD)) {

#if FCONLY

            // FC Mode ICONS

            write_char_xy(10, top_line, 0xCA); // RC-transmitter

            write_char_xy(27, top_line, 0xCC); // small meters m height

            write_char_xy(7, bottom_line, 0x9E); // small v

#else

            // NAVI Mode ICONS

            write_char_xy(5, top_line, 0xCB); // km/h

            write_char_xy(10, top_line, 0xCA); // RC-transmitter

            write_char_xy(16, top_line, 0xD0); // degree symbol

            write_char_xy(27, top_line, 0xCC); // small meters m height

            write_char_xy(20, top_line + 1, 0xB0); // left circle

            write_char_xy(22, top_line + 1, 0xB2); // right circle

            write_char_xy(27, top_line + 1, 0xCC); // small meters m home

            write_char_xy(7, bottom_line, 0x9E); // small v

            write_char_xy(14, bottom_line, 0xD1); // on clock

            write_char_xy(21, bottom_line, 0xD2); // fly clock

            write_char_xy(26, bottom_line, 0xC8); // sat1

            write_char_xy(27, bottom_line, 0xC9); // sat2

            COSD_FLAGS |= COSD_ICONS_WRITTEN;

#endif

        }

        if (rxd_buffer_locked) {

            if (COSD_FLAGS & COSD_FLAG_HUD) {

#if FCONLY

                if (rxd_buffer[2] == 'D') { // FC Data

                    Decode64();

                    debugData = *((DebugOut_t*) pRxData);

                    // init on first data retrival, distinguished by last battery :)

                    if (last_UBat == 255) {

                        auto_config(debugData.Analog[9], &min_UBat);

                    }

                    write_ndigit_number_u(7, top_line, debugData.Analog[10], 100, 0);

                    if (debugData.Analog[10] <= RCLVL_WRN && last_RC_Quality > RCLVL_WRN) {

                        for (uint8_t x = 0; x < 4; x++)

                            write_char_att_xy(7 + x, top_line, BLINK);

                    } else if (debugData.Analog[10] > RCLVL_WRN && last_RC_Quality <= RCLVL_WRN) {

                        for (uint8_t x = 0; x < 4; x++)

                            write_char_att_xy(7 + x, top_line, 0);

                    }

                    last_RC_Quality = debugData.Analog[10];

                    if (debugData.Analog[5] > 300 || debugData.Analog[5] < -300) {

                        // above 10m only write full meters

                        write_ndigit_number_s(23, top_line, debugData.Analog[5] / 30, 1000, 0);

                    } else {

                        // up to 10m write meters.dm

                        write_ndigit_number_s_10th(23, top_line, debugData.Analog[5] / 3, 100, 0);

                    }

                    if (COSD_FLAGS & COSD_FLAG_ARTHORIZON) {

                        draw_artificial_horizon(top_line + 2, bottom_line - 1, debugData.Analog[0], debugData.Analog[1]);

                    }

                    draw_battery(2, bottom_line, min_voltage, debugData.Analog[9], max_voltage);

                    write_ndigit_number_u_10th(3, bottom_line, debugData.Analog[9], 100, 0);

                    if (debugData.Analog[9] <= min_voltage && last_UBat > min_voltage) {

                        for (uint8_t x = 2; x < 8; x++)

                            write_char_att_xy(x, bottom_line, BLINK);

                    } else if (debugData.Analog[9] > min_voltage && last_UBat < min_voltage) {

                        for (uint8_t x = 2; x < 8; x++)

                            write_char_att_xy(x, bottom_line, 0);

                    }

                    // remember last values

                    last_UBat = debugData.Analog[9];

                    /*

                    debugData.Analog[0]); // AngleNick

                    debugData.Analog[1]); // AngleRoll

                    debugData.Analog[5]); // Height

                    debugData.Analog[9]); // Voltage

                    debugData.Analog[10]);// RC Signal

                    debugData.Analog[11]);// Gyro compass

                     */

                    seconds_since_last_data = 0;

                }

#else

                if (rxd_buffer[2] == 'O') { // NC OSD Data

                    Decode64();

                    naviData = *((NaviData_t*) pRxData);

                    // init on first data retrival, distinguished by last battery :)

                    if (last_UBat == 255) {

                        auto_config(naviData.UBat, &min_UBat);

                    }

                    // first line

                    write_ndigit_number_u(2, top_line, (uint16_t) (((uint32_t) naviData.GroundSpeed * (uint32_t) 9) / (uint32_t) 250), 100, 0);

                    write_ndigit_number_u(7, top_line, naviData.RC_Quality, 100, 0);

                    if (naviData.RC_Quality <= RCLVL_WRN && last_RC_Quality > RCLVL_WRN) {

                        for (uint8_t x = 0; x < 4; x++)

                            write_char_att_xy(7 + x, top_line, BLINK);

                    } else if (naviData.RC_Quality > RCLVL_WRN && last_RC_Quality <= RCLVL_WRN) {

                        for (uint8_t x = 0; x < 4; x++)

                            write_char_att_xy(7 + x, top_line, 0);

                    }

                    last_RC_Quality = naviData.RC_Quality;

                    if (naviData.NCFlags & NC_FLAG_NOSERIALLINK) {

                        write_char_xy(11, top_line, 0); // clear

                    } else {

                        write_char_xy(11, top_line, 0xC6); // PC icon

                    }

                    write_ndigit_number_u(13, top_line, naviData.CompassHeading, 100, 0);

                    write_ascii_string(17, top_line, directions[heading_conv(naviData.CompassHeading)]);

                    draw_variometer(21, top_line, naviData.Variometer);

                    //note:lephisto:according to several sources it's /30

                    if (naviData.Altimeter > 300 || naviData.Altimeter < -300) {

                        // above 10m only write full meters

                        write_ndigit_number_s(23, top_line, naviData.Altimeter / 30, 1000, 0);

                    } else {

                        // up to 10m write meters.dm

                        //write_number_u_10th(21, top_line, naviData.Altimeter / 3);

                        write_ndigit_number_s_10th(23, top_line, naviData.Altimeter / 3, 100, 0);

                    }

                    // seccond line

                    draw_compass(11, top_line + 1, naviData.CompassHeading);

                    // TODO: verify correctness

                    uint16_t heading_home = (naviData.HomePositionDeviation.Bearing + 360 - naviData.CompassHeading) % 360;

                    //write_char_xy(21, top_line + 1, arrowdir[heading_conv(heading_home)]);

                    // finer resolution, 0xa0 is first character and we add the index 0 <= index < 16

                    write_char_xy(21, top_line + 1, 0xa0 + heading_fine_conv(heading_home));

                    write_ndigit_number_u(24, top_line + 1, naviData.HomePositionDeviation.Distance / 10, 100, 0);

                    // center

                    if (naviData.MKFlags & FLAG_MOTOR_RUN) { // should be engines running

                        if (!(old_MKFlags & FLAG_MOTOR_RUN)) { // motors just started, clear middle

                            clear();

                            // update flags to paint display again if needed

                            COSD_FLAGS &= ~COSD_ICONS_WRITTEN;

                        }

                        if (COSD_FLAGS & COSD_FLAG_ARTHORIZON) {

                            draw_artificial_horizon(top_line + 2, bottom_line - 1, naviData.AngleNick, naviData.AngleRoll);

                        }

                        // motors are on, assume we were/are flying

                        COSD_FLAGS |= COSD_WASFLYING;

                    } else {

                        // stats

                        if ((COSD_FLAGS & COSD_WASFLYING) && (COSD_FLAGS & COSD_FLAG_STATS)) {

                            write_ascii_string_pgm(2, 4, stats_item_pointers[0]); // max Altitude

                            write_ndigit_number_s(18, 4, max_Altimeter / 30, 1000, 0);

                            write_char_xy(22, 4, 204); // small meters m

                            write_ascii_string_pgm(2, 5, stats_item_pointers[1]); // max Speed

                            write_ndigit_number_u(19, 5, (uint16_t) (((uint32_t) max_GroundSpeed * (uint32_t) 9) / (uint32_t) 250), 100, 0);

                            write_char_xy(22, 5, 203); // km/h

                            write_ascii_string_pgm(2, 6, stats_item_pointers[2]); // max Distance

                            write_ndigit_number_u(19, 6, max_Distance / 10, 100, 0);

                            write_char_xy(22, 6, 204); // small meters m

                            write_ascii_string_pgm(2, 7, stats_item_pointers[3]); // min voltage

                            write_ndigit_number_u_10th(18, 7, min_UBat, 100, 0);

                            write_char_xy(22, 7, 0x9E); // small v

                            write_ascii_string_pgm(2, 8, stats_item_pointers[4]); // max time

                            write_time(16, 8, max_FlyingTime);

                            write_char_xy(22, 8, 210); // fly clock

                            write_ascii_string_pgm(2, 9, stats_item_pointers[5]); // longitude

                            write_gps_pos(15, 9, naviData.CurrentPosition.Longitude);

                            write_ascii_string_pgm(2, 10, stats_item_pointers[6]); // latitude

                            write_gps_pos(15, 10, naviData.CurrentPosition.Latitude);

                        } else if (COSD_FLAGS & COSD_FLAG_ARTHORIZON) { // if no stats there is space horizon

                            draw_artificial_horizon(top_line + 2, bottom_line - 1, naviData.AngleNick, naviData.AngleRoll);

                        }

                    }

                    if (COSD_FLAGS & COSD_FLAG_BIGVARIO) {

                        draw_big_variometer(27, 8, naviData.Variometer);

                    }

                    // bottom line

                    draw_battery(2, bottom_line, min_voltage, naviData.UBat, max_voltage);

                    write_ndigit_number_u_10th(3, bottom_line, naviData.UBat, 100, 0);

                    if (naviData.UBat <= min_voltage && last_UBat > min_voltage) {

                        for (uint8_t x = 2; x < 8; x++)

                            write_char_att_xy(x, bottom_line, BLINK);

                    } else if (naviData.UBat > min_voltage && last_UBat < min_voltage) {

                        for (uint8_t x = 2; x < 8; x++)

                            write_char_att_xy(x, bottom_line, 0);

                    }

                    // remember last values

                    last_UBat = naviData.UBat;

                    write_time(8, bottom_line, uptime);

                    write_time(15, bottom_line, naviData.FlyingTime);

                    write_ndigit_number_u(24, bottom_line, naviData.SatsInUse, 10, 0);

                    if (naviData.NCFlags & NC_FLAG_MANUAL_CONTROL) {

                        write_char_xy(23, bottom_line, 0xB3); // rc transmitter

                    } else {

                        write_char_xy(23, bottom_line, 0); // clear

                    }

                    if (naviData.NCFlags & NC_FLAG_CH) {

                        write_char_xy(27, bottom_line, 231); // gps ch

                    } else if (naviData.NCFlags & NC_FLAG_PH) {

                        write_char_xy(27, bottom_line, 230); // gps ph

                    } else { // (naviData.NCFlags & NC_FLAG_FREE)

                        write_char_xy(27, bottom_line, 201); // sat2 (free)

                    }

                    //write_number_s(8, 5, RxDataLen);

                    //write_number_s(16, 5, setsReceived++);

                    // remember statistics (only when engines running)

                    if (naviData.MKFlags & FLAG_MOTOR_RUN) {

                        if (naviData.Altimeter > max_Altimeter) max_Altimeter = naviData.Altimeter;

                        if (naviData.GroundSpeed > max_GroundSpeed) max_GroundSpeed = naviData.GroundSpeed;

                        if (naviData.HomePositionDeviation.Distance > max_Distance) {

                            max_Distance = naviData.HomePositionDeviation.Distance;

                        }

                        if (naviData.UBat < min_UBat) min_UBat = naviData.UBat;

                        if (naviData.FlyingTime > max_FlyingTime) max_FlyingTime = naviData.FlyingTime;

                    }

                    old_MKFlags = naviData.MKFlags;

                    seconds_since_last_data = 0;

                }

#endif

            }

            rxd_buffer_locked = 0;

        }

        // handle keypress

        if (s1_pressed()) {

            config_menu();

        }

        if (seconds_since_last_data > 2) {

#if FCONLY

            // request data ever 100ms from FC;

            usart1_request_mk_data(0, 'd', 100);