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AP_Frsky_Telem: prevent SPort frame fragmentation #14328

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merged 2 commits into from
May 26, 2020
Merged

AP_Frsky_Telem: prevent SPort frame fragmentation #14328

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de2e88f
AP_Frsky_Telem: prevent SPort frame fragmentation by writing whole 8b…
yaapu May 9, 2020
a1a28e1
AP_Frsky_Telem: removed time constraint to allow SITL regression testing
yaapu May 10, 2020
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173 changes: 88 additions & 85 deletions libraries/AP_Frsky_Telem/AP_Frsky_Telem.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -148,44 +148,44 @@ void AP_Frsky_Telem::process_packet(uint8_t idx)
switch (idx) {
case TEXT: // 0x5000 status text
if (get_next_msg_chunk()) {
send_uint32(SPORT_DATA_FRAME, DIY_FIRST_ID, _msg_chunk.chunk);
send_sport_frame(SPORT_DATA_FRAME, DIY_FIRST_ID, _msg_chunk.chunk);
}
break;
case ATTITUDE: // 0x5006 Attitude and range
send_uint32(SPORT_DATA_FRAME, DIY_FIRST_ID+6, calc_attiandrng());
send_sport_frame(SPORT_DATA_FRAME, DIY_FIRST_ID+6, calc_attiandrng());
break;
case GPS_LAT: // 0x800 GPS lat
// sample both lat and lon at the same time
send_uint32(SPORT_DATA_FRAME, GPS_LONG_LATI_FIRST_ID, calc_gps_latlng(&_passthrough.send_latitude)); // gps latitude or longitude
send_sport_frame(SPORT_DATA_FRAME, GPS_LONG_LATI_FIRST_ID, calc_gps_latlng(&_passthrough.send_latitude)); // gps latitude or longitude
_passthrough.gps_lng_sample = calc_gps_latlng(&_passthrough.send_latitude);
// force the scheduler to select GPS lon as packet that's been waiting the most
// this guarantees that gps coords are sent at max
// _scheduler.avg_polling_period*number_of_downlink_sensors time separation
_scheduler.packet_timer[GPS_LON] = _scheduler.packet_timer[GPS_LAT] - 10000;
break;
case GPS_LON: // 0x800 GPS lon
send_uint32(SPORT_DATA_FRAME, GPS_LONG_LATI_FIRST_ID, _passthrough.gps_lng_sample); // gps longitude
send_sport_frame(SPORT_DATA_FRAME, GPS_LONG_LATI_FIRST_ID, _passthrough.gps_lng_sample); // gps longitude
break;
case VEL_YAW: // 0x5005 Vel and Yaw
send_uint32(SPORT_DATA_FRAME, DIY_FIRST_ID+5, calc_velandyaw());
send_sport_frame(SPORT_DATA_FRAME, DIY_FIRST_ID+5, calc_velandyaw());
break;
case AP_STATUS: // 0x5001 AP status
send_uint32(SPORT_DATA_FRAME, DIY_FIRST_ID+1, calc_ap_status());
send_sport_frame(SPORT_DATA_FRAME, DIY_FIRST_ID+1, calc_ap_status());
break;
case GPS_STATUS: // 0x5002 GPS Status
send_uint32(SPORT_DATA_FRAME, DIY_FIRST_ID+2, calc_gps_status());
send_sport_frame(SPORT_DATA_FRAME, DIY_FIRST_ID+2, calc_gps_status());
break;
case HOME: // 0x5004 Home
send_uint32(SPORT_DATA_FRAME, DIY_FIRST_ID+4, calc_home());
send_sport_frame(SPORT_DATA_FRAME, DIY_FIRST_ID+4, calc_home());
break;
case BATT_2: // 0x5008 Battery 2 status
send_uint32(SPORT_DATA_FRAME, DIY_FIRST_ID+8, calc_batt(1));
send_sport_frame(SPORT_DATA_FRAME, DIY_FIRST_ID+8, calc_batt(1));
break;
case BATT_1: // 0x5003 Battery 1 status
send_uint32(SPORT_DATA_FRAME, DIY_FIRST_ID+3, calc_batt(0));
send_sport_frame(SPORT_DATA_FRAME, DIY_FIRST_ID+3, calc_batt(0));
break;
case PARAM: // 0x5007 parameters
send_uint32(SPORT_DATA_FRAME, DIY_FIRST_ID+7, calc_param());
send_sport_frame(SPORT_DATA_FRAME, DIY_FIRST_ID+7, calc_param());
break;
}
}
Expand Down Expand Up @@ -214,8 +214,8 @@ void AP_Frsky_Telem::send_SPort_Passthrough(void)
prev_byte = _passthrough.new_byte;
_passthrough.new_byte = _port->read();
}
if (prev_byte == START_STOP_SPORT) {
if (_passthrough.new_byte == SENSOR_ID_28) { // byte 0x7E is the header of each poll request
if (prev_byte == FRAME_HEAD) {
if (_passthrough.new_byte == SENSOR_ID_27) { // byte 0x7E is the header of each poll request
run_wfq_scheduler();
}
}
Expand Down Expand Up @@ -256,7 +256,7 @@ void AP_Frsky_Telem::send_SPort(void)
for (int16_t i = 0; i < numc; i++) {
int16_t readbyte = _port->read();
if (_SPort.sport_status == false) {
if (readbyte == START_STOP_SPORT) {
if (readbyte == FRAME_HEAD) {
_SPort.sport_status = true;
}
} else {
Expand All @@ -265,13 +265,13 @@ void AP_Frsky_Telem::send_SPort(void)
case SENSOR_ID_VARIO: // Sensor ID 0
switch (_SPort.vario_call) {
case 0:
send_uint32(SPORT_DATA_FRAME, DATA_ID_BARO_ALT_BP, _SPort_data.alt_nav_meters); // send altitude integer part
send_sport_frame(SPORT_DATA_FRAME, DATA_ID_BARO_ALT_BP, _SPort_data.alt_nav_meters); // send altitude integer part
break;
case 1:
send_uint32(SPORT_DATA_FRAME, DATA_ID_BARO_ALT_AP, _SPort_data.alt_nav_cm); // send altitude decimal part
send_sport_frame(SPORT_DATA_FRAME, DATA_ID_BARO_ALT_AP, _SPort_data.alt_nav_cm); // send altitude decimal part
break;
case 2:
send_uint32(SPORT_DATA_FRAME, DATA_ID_VARIO, _SPort_data.vario_vspd); // send vspeed m/s
send_sport_frame(SPORT_DATA_FRAME, DATA_ID_VARIO, _SPort_data.vario_vspd); // send vspeed m/s
_SPort.vario_refresh = true;
break;
}
Expand All @@ -282,18 +282,18 @@ void AP_Frsky_Telem::send_SPort(void)
case SENSOR_ID_FAS: // Sensor ID 2
switch (_SPort.fas_call) {
case 0:
send_uint32(SPORT_DATA_FRAME, DATA_ID_FUEL, (uint16_t)roundf(_battery.capacity_remaining_pct())); // send battery remaining
send_sport_frame(SPORT_DATA_FRAME, DATA_ID_FUEL, (uint16_t)roundf(_battery.capacity_remaining_pct())); // send battery remaining
break;
case 1:
send_uint32(SPORT_DATA_FRAME, DATA_ID_VFAS, (uint16_t)roundf(_battery.voltage() * 10.0f)); // send battery voltage
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_uint32(SPORT_DATA_FRAME, DATA_ID_CURRENT, (uint16_t)roundf(current * 10.0f)); // send current consumption
send_sport_frame(SPORT_DATA_FRAME, DATA_ID_CURRENT, (uint16_t)roundf(current * 10.0f)); // send current consumption
break;
}
break;
Expand All @@ -305,25 +305,25 @@ void AP_Frsky_Telem::send_SPort(void)
case SENSOR_ID_GPS: // Sensor ID 3
switch (_SPort.gps_call) {
case 0:
send_uint32(SPORT_DATA_FRAME, GPS_LONG_LATI_FIRST_ID, calc_gps_latlng(&_passthrough.send_latitude)); // gps latitude or longitude
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_uint32(SPORT_DATA_FRAME, GPS_LONG_LATI_FIRST_ID, calc_gps_latlng(&_passthrough.send_latitude)); // gps latitude or longitude
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_uint32(SPORT_DATA_FRAME, DATA_ID_GPS_SPEED_BP, _SPort_data.speed_in_meter); // send gps speed integer part
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_uint32(SPORT_DATA_FRAME, DATA_ID_GPS_SPEED_AP, _SPort_data.speed_in_centimeter); // send gps speed decimal part
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_uint32(SPORT_DATA_FRAME, DATA_ID_GPS_ALT_BP, _SPort_data.alt_gps_meters); // send gps altitude integer part
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_uint32(SPORT_DATA_FRAME, DATA_ID_GPS_ALT_AP, _SPort_data.alt_gps_cm); // send gps altitude decimals
send_sport_frame(SPORT_DATA_FRAME, DATA_ID_GPS_ALT_AP, _SPort_data.alt_gps_cm); // send gps altitude decimals
break;
case 6:
send_uint32(SPORT_DATA_FRAME, DATA_ID_GPS_COURS_BP, _SPort_data.yaw); // send heading in degree based on AHRS and not GPS
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;
}
Expand All @@ -334,10 +334,10 @@ void AP_Frsky_Telem::send_SPort(void)
case SENSOR_ID_SP2UR: // Sensor ID 6
switch (_SPort.various_call) {
case 0 :
send_uint32(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)
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_uint32(SPORT_DATA_FRAME, DATA_ID_TEMP1, gcs().custom_mode()); // send flight mode
send_sport_frame(SPORT_DATA_FRAME, DATA_ID_TEMP1, gcs().custom_mode()); // send flight mode
break;
}
if (++_SPort.various_call > 1) {
Expand Down Expand Up @@ -422,79 +422,82 @@ void AP_Frsky_Telem::loop(void)
}
}

/*
* build up the frame's crc
* for FrSky SPort protocol (X-receivers)
*/
void AP_Frsky_Telem::calc_crc(uint8_t byte)
{
_crc += byte; //0-1FF
_crc += _crc >> 8; //0-100
_crc &= 0xFF;
}

/*
* send the frame's crc at the end of the frame
* for FrSky SPort protocol (X-receivers)
*/
void AP_Frsky_Telem::send_crc(void)
{
send_byte(0xFF - _crc);
_crc = 0;
}


/*
send 1 byte and do byte stuffing
*/
void AP_Frsky_Telem::send_byte(uint8_t byte)
{
if (_protocol == AP_SerialManager::SerialProtocol_FrSky_D) { // FrSky D protocol (D-receivers)
if (byte == START_STOP_D) {
_port->write(0x5D);
_port->write(0x3E);
} else if (byte == BYTESTUFF_D) {
_port->write(0x5D);
_port->write(0x3D);
} else {
_port->write(byte);
}
} else { // FrSky SPort protocol (X-receivers)
if (byte == START_STOP_SPORT) {
_port->write(0x7D);
_port->write(0x5E);
} else if (byte == BYTESTUFF_SPORT) {
_port->write(0x7D);
_port->write(0x5D);
} else {
_port->write(byte);
}
calc_crc(byte);
if (byte == START_STOP_D) {
_port->write(0x5D);
_port->write(0x3E);
} else if (byte == BYTESTUFF_D) {
_port->write(0x5D);
_port->write(0x3D);
} else {
_port->write(byte);
}
}

/*
* send one uint32 frame of FrSky data - for FrSky SPort protocol (X-receivers)
* send an 8 bytes SPort frame of FrSky data - for FrSky SPort protocol (X-receivers)
*/
void AP_Frsky_Telem::send_uint32(uint8_t frame, uint16_t id, uint32_t data)
void AP_Frsky_Telem::send_sport_frame(uint8_t frame, uint16_t appid, uint32_t data)
{
if (use_external_data) {
external_data.frame = frame;
external_data.appid = id;
external_data.appid = appid;
external_data.data = data;
external_data.pending = true;
return;
}
send_byte(frame); // frame type
uint8_t *bytes = (uint8_t*)&id;
send_byte(bytes[0]); // LSB
send_byte(bytes[1]); // MSB
bytes = (uint8_t*)&data;
send_byte(bytes[0]); // LSB
send_byte(bytes[1]);
send_byte(bytes[2]);
send_byte(bytes[3]); // MSB
send_crc();

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;
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Don't need to cast this


// 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];
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Suggested change
uint8_t c = buf[i];
const uint8_t c = buf[i];

if (c == FRAME_DLE || buf[i] == FRAME_HEAD) {
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Suggested change
if (c == FRAME_DLE || buf[i] == FRAME_HEAD) {
if (c == FRAME_DLE || c == 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);
}

/*
Expand Down
12 changes: 6 additions & 6 deletions libraries/AP_Frsky_Telem/AP_Frsky_Telem.h
View file
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Original file line number Diff line number Diff line change
Expand Up @@ -57,14 +57,16 @@ for FrSky SPort and SPort Passthrough (OpenTX) protocols (X-receivers)
#define SENSOR_ID_FAS 0x22 // Sensor ID 2
#define SENSOR_ID_GPS 0x83 // Sensor ID 3
#define SENSOR_ID_SP2UR 0xC6 // Sensor ID 6
#define SENSOR_ID_28 0x1B // Sensor ID 28
#define SENSOR_ID_27 0x1B // Sensor ID 27

// FrSky data IDs
#define GPS_LONG_LATI_FIRST_ID 0x0800
#define DIY_FIRST_ID 0x5000

#define START_STOP_SPORT 0x7E
#define BYTESTUFF_SPORT 0x7D
#define FRAME_HEAD 0x7E
#define FRAME_DLE 0x7D
#define FRAME_XOR 0x20

#define SPORT_DATA_FRAME 0x10
/*
for FrSky SPort Passthrough
Expand Down Expand Up @@ -218,11 +220,9 @@ class AP_Frsky_Telem : public AP_RCTelemetry {
// tick - main call to send updates to transmitter (called by scheduler at 1kHz)
void loop(void);
// methods related to the nuts-and-bolts of sending data
void calc_crc(uint8_t byte);
void send_crc(void);
void send_byte(uint8_t value);
void send_uint16(uint16_t id, uint16_t data);
void send_uint32(uint8_t frame, uint16_t id, uint32_t data);
void send_sport_frame(uint8_t frame, uint16_t appid, uint32_t data);

// methods to convert flight controller data to FrSky SPort Passthrough (OpenTX) format
bool get_next_msg_chunk(void) override;
Expand Down