static bool gpsNewFrameNMEA(char c)
{
static gpsDataNmea_t gps_Msg;
uint8_t frameOK = 0;
static uint8_t param = 0, offset = 0, parity = 0;
static char string[15];
static uint8_t checksum_param, gps_frame = NO_FRAME;
static uint8_t svMessageNum = 0;
uint8_t svSatNum = 0, svPacketIdx = 0, svSatParam = 0;
switch (c) {
case '$':
param = 0;
offset = 0;
parity = 0;
break;
case ',':
case '*':
string[offset] = 0;
if (param == 0) { //frame identification
gps_frame = NO_FRAME;
if (string[0] == 'G' && string[1] == 'P' && string[2] == 'G' && string[3] == 'G' && string[4] == 'A')
gps_frame = FRAME_GGA;
if (string[0] == 'G' && string[1] == 'P' && string[2] == 'R' && string[3] == 'M' && string[4] == 'C')
gps_frame = FRAME_RMC;
if (string[0] == 'G' && string[1] == 'P' && string[2] == 'G' && string[3] == 'S' && string[4] == 'V')
gps_frame = FRAME_GSV;
}
switch (gps_frame) {
case FRAME_GGA: //************* GPGGA FRAME parsing
switch(param) {
// case 1: // Time information
// break;
case 2:
gps_Msg.latitude = GPS_coord_to_degrees(string);
break;
case 3:
if (string[0] == 'S')
gps_Msg.latitude *= -1;
break;
case 4:
gps_Msg.longitude = GPS_coord_to_degrees(string);
break;
case 5:
if (string[0] == 'W')
gps_Msg.longitude *= -1;
break;
case 6:
if (string[0] > '0') {
ENABLE_STATE(GPS_FIX);
} else {
DISABLE_STATE(GPS_FIX);
}
break;
case 7:
gps_Msg.numSat = grab_fields(string, 0);
break;
case 9:
gps_Msg.altitude = grab_fields(string, 0); // altitude in meters added by Mis
break;
}
break;
case FRAME_RMC: //************* GPRMC FRAME parsing
switch(param) {
case 7:
gps_Msg.speed = ((grab_fields(string, 1) * 5144L) / 1000L); // speed in cm/s added by Mis
break;
case 8:
gps_Msg.ground_course = (grab_fields(string, 1)); // ground course deg * 10
break;
}
break;
case FRAME_GSV:
switch(param) {
/*case 1:
// Total number of messages of this type in this cycle
break; */
case 2:
// Message number
svMessageNum = grab_fields(string, 0);
break;
case 3:
// Total number of SVs visible
GPS_numCh = grab_fields(string, 0);
break;
}
if(param < 4)
break;
svPacketIdx = (param - 4) / 4 + 1; // satellite number in packet, 1-4
svSatNum = svPacketIdx + (4 * (svMessageNum - 1)); // global satellite number
svSatParam = param - 3 - (4 * (svPacketIdx - 1)); // parameter number for satellite
if(svSatNum > GPS_SV_MAXSATS)
break;
switch(svSatParam) {
case 1:
// SV PRN number
GPS_svinfo_chn[svSatNum - 1] = svSatNum;
GPS_svinfo_svid[svSatNum - 1] = grab_fields(string, 0);
break;
/*case 2:
// Elevation, in degrees, 90 maximum
break;
case 3:
// Azimuth, degrees from True North, 000 through 359
break; */
case 4:
// SNR, 00 through 99 dB (null when not tracking)
GPS_svinfo_cno[svSatNum - 1] = grab_fields(string, 0);
GPS_svinfo_quality[svSatNum - 1] = 0; // only used by ublox
break;
}
GPS_svInfoReceivedCount++;
break;
}
param++;
offset = 0;
if (c == '*')
checksum_param = 1;
else
parity ^= c;
break;
case '\r':
case '\n':
if (checksum_param) { //parity checksum
shiftPacketLog();
uint8_t checksum = 16 * ((string[0] >= 'A') ? string[0] - 'A' + 10 : string[0] - '0') + ((string[1] >= 'A') ? string[1] - 'A' + 10 : string[1] - '0');
if (checksum == parity) {
*gpsPacketLogChar = LOG_IGNORED;
GPS_packetCount++;
switch (gps_frame) {
case FRAME_GGA:
*gpsPacketLogChar = LOG_NMEA_GGA;
frameOK = 1;
if (STATE(GPS_FIX)) {
GPS_coord[LAT] = gps_Msg.latitude;
GPS_coord[LON] = gps_Msg.longitude;
GPS_numSat = gps_Msg.numSat;
GPS_altitude = gps_Msg.altitude;
}
break;
case FRAME_RMC:
*gpsPacketLogChar = LOG_NMEA_RMC;
GPS_speed = gps_Msg.speed;
GPS_ground_course = gps_Msg.ground_course;
break;
} // end switch
} else {
*gpsPacketLogChar = LOG_ERROR;
}
}
checksum_param = 0;
break;
default:
if (offset < 15)
string[offset++] = c;
if (!checksum_param)
parity ^= c;
}
return frameOK;
}
static bool gpsNewFrameUBLOX(uint8_t data)
{
bool parsed = false;
switch (_step) {
case 0: // Sync char 1 (0xB5)
if (PREAMBLE1 == data) {
_skip_packet = false;
_step++;
} else {
GPS_garbageByteCount++;
}
break;
case 1: // Sync char 2 (0x62)
if (PREAMBLE2 != data) {
_step = 0;
break;
}
_step++;
break;
case 2: // Class
_step++;
_class = data;
_ck_b = _ck_a = data; // reset the checksum accumulators
break;
case 3: // Id
_step++;
_ck_b += (_ck_a += data); // checksum byte
_msg_id = data;
break;
case 4: // Payload length (part 1)
_step++;
_ck_b += (_ck_a += data); // checksum byte
_payload_length = data; // payload length low byte
break;
case 5: // Payload length (part 2)
_step++;
_ck_b += (_ck_a += data); // checksum byte
_payload_length |= (uint16_t)(data << 8);
if (_payload_length > MAX_UBLOX_PAYLOAD_SIZE ) {
// we can't receive the whole packet, just log the error and start searching for the next packet.
shiftPacketLog();
*gpsPacketLogChar = LOG_SKIPPED;
gpsData.errors++;
_step = 0;
break;
}
if (_payload_length > UBLOX_BUFFER_SIZE) {
_skip_packet = true;
}
// prepare to receive payload
_payload_counter = 0;
if (_payload_length == 0) {
_step = 7;
}
break;
case 6:
_ck_b += (_ck_a += data); // checksum byte
if (_payload_counter < UBLOX_BUFFER_SIZE) {
_buffer.bytes[_payload_counter] = data;
}
// NOTE: check counter BEFORE increasing so that a payload_size of 65535 is correctly handled. This can happen if garbage data is received.
if (_payload_counter == _payload_length - 1) {
_step++;
}
_payload_counter++;
break;
case 7:
_step++;
if (_ck_a != data) {
_skip_packet = true; // bad checksum
gpsData.errors++;
}
break;
case 8:
_step = 0;
shiftPacketLog();
if (_ck_b != data) {
*gpsPacketLogChar = LOG_ERROR;
gpsData.errors++;
break; // bad checksum
}
GPS_packetCount++;
if (_skip_packet) {
*gpsPacketLogChar = LOG_SKIPPED;
break;
}
if (UBLOX_parse_gps()) {
parsed = true;
}
}
return parsed;
}
static bool gpsNewFrameUBLOX(uint8_t data)
{
bool parsed = false;
switch (_step) {
case 0: // Sync char 1 (0xB5)
if (PREAMBLE1 == data) {
_skip_packet = false;
_step++;
}
break;
case 1: // Sync char 2 (0x62)
if (PREAMBLE2 != data) {
_step = 0;
break;
}
_step++;
break;
case 2: // Class
_step++;
_class = data;
_ck_b = _ck_a = data; // reset the checksum accumulators
break;
case 3: // Id
_step++;
_ck_b += (_ck_a += data); // checksum byte
_msg_id = data;
break;
case 4: // Payload length (part 1)
_step++;
_ck_b += (_ck_a += data); // checksum byte
_payload_length = data; // payload length low byte
break;
case 5: // Payload length (part 2)
_step++;
_ck_b += (_ck_a += data); // checksum byte
_payload_length += (uint16_t)(data << 8);
if (_payload_length > UBLOX_PAYLOAD_SIZE) {
_skip_packet = true;
}
_payload_counter = 0; // prepare to receive payload
if (_payload_length == 0) {
_step = 7;
}
break;
case 6:
_ck_b += (_ck_a += data); // checksum byte
if (_payload_counter < UBLOX_PAYLOAD_SIZE) {
_buffer.bytes[_payload_counter] = data;
}
if (++_payload_counter >= _payload_length) {
_step++;
}
break;
case 7:
_step++;
if (_ck_a != data) {
_skip_packet = true; // bad checksum
gpsData.errors++;
}
break;
case 8:
_step = 0;
shiftPacketLog();
if (_ck_b != data) {
*gpsPacketLogChar = LOG_ERROR;
gpsData.errors++;
break; // bad checksum
}
GPS_packetCount++;
if (_skip_packet) {
*gpsPacketLogChar = LOG_SKIPPED;
break;
}
if (UBLOX_parse_gps()) {
parsed = true;
}
}
return parsed;
}
