#include "AP_Frsky_SPort.h"
#include <AP_BattMonitor/AP_BattMonitor.h>
#include <AP_GPS/AP_GPS.h>
#include <GCS_MAVLink/GCS.h>
/*
* send telemetry data
* for FrSky SPort protocol (X-receivers)
*/
void AP_Frsky_SPort::send(void)
{
int16_t numc;
numc = _port->available();
// check if available is negative
if (numc < 0) {
return;
}
// this is the constant for hub data frame
if (_port->txspace() < 19) {
return;
}
if (numc == 0) {
// no serial data to process do bg tasks
if (_SPort.vario_refresh) {
calc_nav_alt(); // nav altitude is not recalculated until all of it has been sent
_SPort.vario_refresh = false;
}
if (_SPort.gps_refresh) {
calc_gps_position(); // gps data is not recalculated until all of it has been sent
_SPort.gps_refresh = false;
}
return;
}
for (int16_t i = 0; i < numc; i++) {
int16_t readbyte = _port->read();
if (_SPort.sport_status == false) {
if (readbyte == FRAME_HEAD) {
_SPort.sport_status = true;
}
} else {
const AP_BattMonitor &_battery = AP::battery();
switch (readbyte) {
case SENSOR_ID_VARIO: // Sensor ID 0
switch (_SPort.vario_call) {
case 0:
send_sport_frame(SPORT_DATA_FRAME, DATA_ID_BARO_ALT_BP, _SPort_data.alt_nav_meters); // send altitude integer part
break;
case 1:
send_sport_frame(SPORT_DATA_FRAME, DATA_ID_BARO_ALT_AP, _SPort_data.alt_nav_cm); // send altitude decimal part
break;
case 2:
send_sport_frame(SPORT_DATA_FRAME, DATA_ID_VARIO, _SPort_data.vario_vspd); // send vspeed m/s
_SPort.vario_refresh = true;
break;
}
if (++_SPort.vario_call > 2) {
_SPort.vario_call = 0;
}
break;
case SENSOR_ID_FAS: // Sensor ID 2
switch (_SPort.fas_call) {
case 0:
send_sport_frame(SPORT_DATA_FRAME, DATA_ID_FUEL, (uint16_t)roundf(_battery.capacity_remaining_pct())); // send battery remaining
break;
case 1:
send_sport_frame(SPORT_DATA_FRAME, DATA_ID_VFAS, (uint16_t)roundf(_battery.voltage() * 10.0f)); // send battery voltage
break;
case 2: {
float current;
if (!_battery.current_amps(current)) {
current = 0;
}
send_sport_frame(SPORT_DATA_FRAME, DATA_ID_CURRENT, (uint16_t)roundf(current * 10.0f)); // send current consumption
break;
}
break;
}
if (++_SPort.fas_call > 2) {
_SPort.fas_call = 0;
}
break;
case SENSOR_ID_GPS: // Sensor ID 3
switch (_SPort.gps_call) {
case 0:
send_sport_frame(SPORT_DATA_FRAME, GPS_LONG_LATI_FIRST_ID, calc_gps_latlng(&_passthrough.send_latitude)); // gps latitude or longitude
break;
case 1:
send_sport_frame(SPORT_DATA_FRAME, GPS_LONG_LATI_FIRST_ID, calc_gps_latlng(&_passthrough.send_latitude)); // gps latitude or longitude
break;
case 2:
send_sport_frame(SPORT_DATA_FRAME, DATA_ID_GPS_SPEED_BP, _SPort_data.speed_in_meter); // send gps speed integer part
break;
case 3:
send_sport_frame(SPORT_DATA_FRAME, DATA_ID_GPS_SPEED_AP, _SPort_data.speed_in_centimeter); // send gps speed decimal part
break;
case 4:
send_sport_frame(SPORT_DATA_FRAME, DATA_ID_GPS_ALT_BP, _SPort_data.alt_gps_meters); // send gps altitude integer part
break;
case 5:
send_sport_frame(SPORT_DATA_FRAME, DATA_ID_GPS_ALT_AP, _SPort_data.alt_gps_cm); // send gps altitude decimals
break;
case 6:
send_sport_frame(SPORT_DATA_FRAME, DATA_ID_GPS_COURS_BP, _SPort_data.yaw); // send heading in degree based on AHRS and not GPS
_SPort.gps_refresh = true;
break;
}
if (++_SPort.gps_call > 6) {
_SPort.gps_call = 0;
}
break;
case SENSOR_ID_SP2UR: // Sensor ID 6
switch (_SPort.various_call) {
case 0 :
send_sport_frame(SPORT_DATA_FRAME, DATA_ID_TEMP2, (uint16_t)(AP::gps().num_sats() * 10 + AP::gps().status())); // send GPS status and number of satellites as num_sats*10 + status (to fit into a uint8_t)
break;
case 1:
send_sport_frame(SPORT_DATA_FRAME, DATA_ID_TEMP1, gcs().custom_mode()); // send flight mode
break;
}
if (++_SPort.various_call > 1) {
_SPort.various_call = 0;
}
break;
}
_SPort.sport_status = false;
}
}
}
/*
* prepare gps latitude/longitude data
* for FrSky SPort Passthrough (OpenTX) protocol (X-receivers)
*/
uint32_t AP_Frsky_SPort::calc_gps_latlng(bool *send_latitude)
{
uint32_t latlng;
const Location &loc = AP::gps().location(0); // use the first gps instance (same as in send_mavlink_gps_raw)
// alternate between latitude and longitude
if ((*send_latitude) == true) {
if (loc.lat < 0) {
latlng = ((labs(loc.lat)/100)*6) | 0x40000000;
} else {
latlng = ((labs(loc.lat)/100)*6);
}
(*send_latitude) = false;
} else {
if (loc.lng < 0) {
latlng = ((labs(loc.lng)/100)*6) | 0xC0000000;
} else {
latlng = ((labs(loc.lng)/100)*6) | 0x80000000;
}
(*send_latitude) = true;
}
return latlng;
}
/*
* send an 8 bytes SPort frame of FrSky data - for FrSky SPort protocol (X-receivers)
*/
void AP_Frsky_SPort::send_sport_frame(uint8_t frame, uint16_t appid, uint32_t data)
{
uint8_t buf[8];
buf[0] = frame;
buf[1] = appid & 0xFF;
buf[2] = appid >> 8;
memcpy(&buf[3], &data, 4);
uint16_t sum = 0;
for (uint8_t i=0; i<sizeof(buf)-1; i++) {
sum += buf[i];
sum += sum >> 8;
sum &= 0xFF;
}
sum = 0xff - ((sum & 0xff) + (sum >> 8));
buf[7] = (uint8_t)sum;
// perform byte stuffing per SPort spec
uint8_t len = 0;
uint8_t buf2[sizeof(buf)*2+1];
for (uint8_t i=0; i<sizeof(buf); i++) {
uint8_t c = buf[i];
if (c == FRAME_DLE || buf[i] == FRAME_HEAD) {
buf2[len++] = FRAME_DLE;
buf2[len++] = c ^ FRAME_XOR;
} else {
buf2[len++] = c;
}
}
#ifndef HAL_BOARD_SITL
/*
check that we haven't been too slow in responding to the new
UART data. If we respond too late then we will overwrite the next
polling frame.
SPort poll-to-pool period is 11.65ms, a frame takes 1.38ms
this leaves us with up to 10ms to respond but to play it safe we
allow no more than 7500us
*/
uint64_t tend = _port->receive_time_constraint_us(1);
uint64_t now = AP_HAL::micros64();
uint64_t tdelay = now - tend;
if (tdelay > 7500) {
// we've been too slow in responding
return;
}
#endif
_port->write(buf2, len);
}