betaflight/src/telemetry_hott.c

/*
 * telemetry_hott.c
 *
 *  Created on: 6 Apr 2014
 *      Authors:
 *      Dominic Clifton - Hydra - Software Serial, Electronics, Hardware Integration and debugging, HoTT Code cleanup and fixes, general telemetry improvements.
 *      Carsten Giesen - cGiesen - Baseflight port
 *      Oliver Bayer - oBayer - MultiWii-HoTT, HoTT reverse engineering
 *
 * It should be noted that the initial cut of code that deals with the handling of requests and formatting and
 * sending of responses comes from the MultiWii-Meets-HoTT and MultiHoTT-module projects
 *
 * https://github.com/obayer/MultiWii-HoTT
 * https://github.com/oBayer/MultiHoTT-Module
 *
 * HoTT is implemented in Graupner equipment using a bi-directional protocol over a single wire.
 *
 * Generally the receiver sends a single request byte out using normal uart signals, then waits a short period for a
 * multiple byte response and checksum byte before it sends out the next request byte.
 * Each response byte must be send with a protocol specific delay between them.
 *
 * Serial ports use two wires but HoTT uses a single wire so some electronics are required so that
 * the signals don't get mixed up.  When baseflight transmits it should not receive it's own transmission.
 *
 * Connect as follows:
 * HoTT TX/RX -> Serial RX (connect directly)
 * Serial TX -> 1N4148 Diode -(|  )-> HoTT TX/RX (connect via diode)
 *
 * The diode should be arranged to allow the data signals to flow the right way
 * -(|  )- == Diode, | indicates cathode marker.
 *
 * As noticed by Skrebber the GR-12 (and probably GR-16/24, too) are based on a PIC 24FJ64GA-002, which digitals pins are 5V tolerant.
 *
 * Note: The softserial ports are not listed as 5V tolerant in the STM32F103xx data sheet pinouts and pin description
 * section.  Verify if you require a 5v/3.3v level shifters.  The softserial port should not be inverted.
 *
 * Technically it is possible to use less components and disable softserial RX when transmitting but that is
 * not currently supported.
 *
 * There is a technical discussion (in German) about HoTT here
 * http://www.rc-network.de/forum/showthread.php/281496-Graupner-HoTT-Telemetrie-Sensoren-Eigenbau-DIY-Telemetrie-Protokoll-entschl%C3%BCsselt/page21
 */

#include "board.h"
#include "mw.h"

#include "drivers/serial_common.h"
#include "serial_common.h"

#include "gps_common.h"

#include "telemetry_hott.h"


const uint8_t kHoTTv4BinaryPacketSize = 45;
const uint8_t kHoTTv4TextPacketSize = 173;
static HoTTV4GPSModule_t HoTTV4GPSModule;
static HoTTV4ElectricAirModule_t HoTTV4ElectricAirModule;

static void hottV4SerialWrite(uint8_t c);

static void hottV4Respond(uint8_t *data, uint8_t size);
static void hottV4FormatAndSendGPSResponse(void);
static void hottV4GPSUpdate(void);
static void hottV4FormatAndSendEAMResponse(void);
static void hottV4EAMUpdateBattery(void);
static void hottV4EAMUpdateTemperatures(void);
bool batteryWarning;

/*
 * Sends HoTTv4 capable GPS telemetry frame.
 */

void hottV4FormatAndSendGPSResponse(void)
{
    memset(&HoTTV4GPSModule, 0, sizeof(HoTTV4GPSModule));

    // Minimum data set for EAM
    HoTTV4GPSModule.startByte = 0x7C;
    HoTTV4GPSModule.sensorID = HOTTV4_GPS_SENSOR_ID;
    HoTTV4GPSModule.sensorTextID = HOTTV4_GPS_SENSOR_TEXT_ID;
    HoTTV4GPSModule.endByte = 0x7D;

    // Reset alarms
    HoTTV4GPSModule.alarmTone = 0x0;
    HoTTV4GPSModule.alarmInverse1 = 0x0;

    hottV4GPSUpdate();

    hottV4Respond((uint8_t*)&HoTTV4GPSModule, sizeof(HoTTV4GPSModule));
}

void hottV4GPSUpdate(void)
{
    // Number of Satelites
    HoTTV4GPSModule.GPSNumSat=GPS_numSat;
    if (f.GPS_FIX > 0) {
        // GPS fix
        HoTTV4GPSModule.GPS_fix = 0x66; // Displays a 'f' for fix

        // latitude
        HoTTV4GPSModule.LatitudeNS=(GPS_coord[LAT]<0);
        uint8_t deg = GPS_coord[LAT] / 100000;
        uint32_t sec = (GPS_coord[LAT] - (deg * 100000)) * 6;
        uint8_t min = sec / 10000;
        sec = sec % 10000;
        uint16_t degMin = (deg * 100) + min;
        HoTTV4GPSModule.LatitudeMinLow = degMin;
        HoTTV4GPSModule.LatitudeMinHigh = degMin >> 8;
        HoTTV4GPSModule.LatitudeSecLow = sec;
        HoTTV4GPSModule.LatitudeSecHigh = sec >> 8;

        // longitude
        HoTTV4GPSModule.longitudeEW=(GPS_coord[LON]<0);
        deg = GPS_coord[LON] / 100000;
        sec = (GPS_coord[LON] - (deg * 100000)) * 6;
        min = sec / 10000;
        sec = sec % 10000;
        degMin = (deg * 100) + min;
        HoTTV4GPSModule.longitudeMinLow = degMin;
        HoTTV4GPSModule.longitudeMinHigh = degMin >> 8;
        HoTTV4GPSModule.longitudeSecLow = sec;
        HoTTV4GPSModule.longitudeSecHigh = sec >> 8;

        // GPS Speed in km/h
        uint16_t speed = (GPS_speed / 100) * 36; // 0.1m/s * 0.36 = km/h
        HoTTV4GPSModule.GPSSpeedLow = speed & 0x00FF;
        HoTTV4GPSModule.GPSSpeedHigh = speed >> 8;

        // Distance to home
        HoTTV4GPSModule.distanceLow = GPS_distanceToHome & 0x00FF;
        HoTTV4GPSModule.distanceHigh = GPS_distanceToHome >> 8;

        // Altitude
        HoTTV4GPSModule.altitudeLow = GPS_altitude & 0x00FF;
        HoTTV4GPSModule.altitudeHigh = GPS_altitude >> 8;

        // Direction to home
        HoTTV4GPSModule.HomeDirection = GPS_directionToHome;
    } else {
        HoTTV4GPSModule.GPS_fix = 0x20; // Displays a ' ' to show nothing or clear the old value
    }
}

/**
 * Writes cell 1-4 high, low values and if not available
 * calculates vbat.
 */
static void hottV4EAMUpdateBattery(void)
{
#if 0
    HoTTV4ElectricAirModule.cell1L = 4.2f * 10 * 5; // 2mv step
    HoTTV4ElectricAirModule.cell1H = 0;

    HoTTV4ElectricAirModule.cell2L = 0;
    HoTTV4ElectricAirModule.cell2H = 0;

    HoTTV4ElectricAirModule.cell3L = 0;
    HoTTV4ElectricAirModule.cell3H = 0;

    HoTTV4ElectricAirModule.cell4L = 0;
    HoTTV4ElectricAirModule.cell4H = 0;
#endif

    HoTTV4ElectricAirModule.driveVoltageLow = vbat & 0xFF;
    HoTTV4ElectricAirModule.driveVoltageHigh = vbat >> 8;
    HoTTV4ElectricAirModule.battery1Low = vbat & 0xFF;
    HoTTV4ElectricAirModule.battery1High = vbat >> 8;

#if 0
    HoTTV4ElectricAirModule.battery2Low = 0 & 0xFF;
    HoTTV4ElectricAirModule.battery2High = 0 >> 8;

    if (batteryWarning) {
        HoTTV4ElectricAirModule.alarmTone = HoTTv4NotificationUndervoltage;
        HoTTV4ElectricAirModule.alarmInverse1 |= 0x80; // Invert Voltage display
    }
#endif
}

static void hottV4EAMUpdateTemperatures(void)
{
    HoTTV4ElectricAirModule.temp1 = 20 + 0;
    HoTTV4ElectricAirModule.temp2 = 20;

#if 0
    if (HoTTV4ElectricAirModule.temp1 >= (20 + MultiHoTTModuleSettings.alarmTemp1)) {
        HoTTV4ElectricAirModule.alarmTone = HoTTv4NotificationMaxTemperature;
        HoTTV4ElectricAirModule.alarmInverse |= 0x8; // Invert Temp1 display
    }
#endif
}


/**
 * Sends HoTTv4 capable EAM telemetry frame.
 */
void hottV4FormatAndSendEAMResponse(void)
{
    memset(&HoTTV4ElectricAirModule, 0, sizeof(HoTTV4ElectricAirModule));

    // Minimum data set for EAM
    HoTTV4ElectricAirModule.startByte = 0x7C;
    HoTTV4ElectricAirModule.sensorID = HOTTV4_ELECTRICAL_AIR_SENSOR_ID;
    HoTTV4ElectricAirModule.sensorTextID = HOTTV4_ELECTRICAL_AIR_SENSOR_TEXT_ID;
    HoTTV4ElectricAirModule.endByte = 0x7D;

    // Reset alarms
    HoTTV4ElectricAirModule.alarmTone = 0x0;
    HoTTV4ElectricAirModule.alarmInverse1 = 0x0;

    hottV4EAMUpdateBattery();
    hottV4EAMUpdateTemperatures();

    HoTTV4ElectricAirModule.current = 0 / 10;
    HoTTV4ElectricAirModule.height = OFFSET_HEIGHT + 0;
    HoTTV4ElectricAirModule.m2s = OFFSET_M2S;
    HoTTV4ElectricAirModule.m3s = OFFSET_M3S;

    hottV4Respond((uint8_t*)&HoTTV4ElectricAirModule, sizeof(HoTTV4ElectricAirModule));
}

static void hottV4Respond(uint8_t *data, uint8_t size)
{
    serialSetMode(serialPorts.telemport, MODE_TX);

    uint16_t crc = 0;
    uint8_t i;

    for (i = 0; i < size - 1; i++) {
        crc += data[i];
        hottV4SerialWrite(data[i]);

        // Protocol specific delay between each transmitted byte
        delayMicroseconds(HOTTV4_TX_DELAY);
    }

    hottV4SerialWrite(crc & 0xFF);

    delayMicroseconds(HOTTV4_TX_DELAY);

    serialSetMode(serialPorts.telemport, MODE_RX);
}

static void hottV4SerialWrite(uint8_t c)
{
    serialWrite(serialPorts.telemport, c);
}

void configureHoTTTelemetryPort(void)
{
    // TODO set speed here to 19200?
    serialSetMode(serialPorts.telemport, MODE_RX);
}

void freeHoTTTelemetryPort(void)
{
    serialSetMode(serialPorts.telemport, MODE_RXTX);
}

void handleHoTTTelemetry(void)
{
    uint8_t c;

    while (serialTotalBytesWaiting(serialPorts.telemport) > 0) {
        c = serialRead(serialPorts.telemport);

        // Protocol specific waiting time to avoid collisions
        delay(5);

        switch (c) {
        case 0x8A:
            if (sensors(SENSOR_GPS)) hottV4FormatAndSendGPSResponse();
            break;
        case 0x8E:
            hottV4FormatAndSendEAMResponse();
            break;
        }
    }
}