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#include <inttypes.h> |
#include "ubx.h" |
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// ubx protocol parser state machine |
#define UBXSTATE_IDLE 0 |
#define UBXSTATE_SYNC1 1 |
#define UBXSTATE_SYNC2 2 |
#define UBXSTATE_CLASS 3 |
#define UBXSTATE_LEN1 4 |
#define UBXSTATE_LEN2 5 |
#define UBXSTATE_DATA 6 |
#define UBXSTATE_CKA 7 |
#define UBXSTATE_CKB 8 |
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// ublox protocoll identifier |
#define UBX_CLASS_NAV 0x01 |
#define UBX_ID_POSLLH 0x02 |
#define UBX_ID_POSUTM 0x08 |
#define UBX_ID_STATUS 0x03 |
#define UBX_ID_VELNED 0x12 |
#define UBX_SYNC1_CHAR 0xB5 |
#define UBX_SYNC2_CHAR 0x62 |
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typedef struct { |
uint32_t ITOW; // ms GPS Millisecond Time of Week |
uint8_t GPSfix; // GPSfix Type, range 0..6 |
uint8_t Flags; // Navigation Status Flags |
uint8_t DiffS; // Differential Status |
uint8_t res; // reserved |
uint32_t TTFF; // Time to first fix (millisecond time tag) |
uint32_t MSSS; // Milliseconds since Startup / Reset |
uint8_t packetStatus; |
} GPS_STATUS_t; |
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typedef struct { |
uint32_t ITOW; // ms GPS Millisecond Time of Week |
int32_t LON; // 1e-07 deg Longitude |
int32_t LAT; // 1e-07 deg Latitude |
int32_t HEIGHT; // mm Height above Ellipsoid |
int32_t HMSL; // mm Height above mean sea level |
uint32_t Hacc; // mm Horizontal Accuracy Estimate |
uint32_t Vacc; // mm Vertical Accuracy Estimate |
uint8_t packetStatus; |
} GPS_POSLLH_t; |
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typedef struct { |
uint32_t ITOW; // ms GPS Millisecond Time of Week |
int32_t EAST; // cm UTM Easting |
int32_t NORTH; // cm UTM Nording |
int32_t ALT; // cm altitude |
uint8_t ZONE; // UTM zone number |
uint8_t HEM; // Hemisphere Indicator (0=North, 1=South) |
uint8_t packetStatus; |
} GPS_POSUTM_t; |
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typedef struct { |
uint32_t ITOW; // ms GPS Millisecond Time of Week |
int32_t VEL_N; // cm/s NED north velocity |
int32_t VEL_E; // cm/s NED east velocity |
int32_t VEL_D; // cm/s NED down velocity |
uint32_t Speed; // cm/s Speed (3-D) |
uint32_t GSpeed; // cm/s Ground Speed (2-D) |
int32_t Heading; // 1e-05 deg Heading 2-D |
uint32_t SAcc; // cm/s Speed Accuracy Estimate |
uint32_t CAcc; // deg Course / Heading Accuracy Estimate |
uint8_t packetStatus; |
} GPS_VELNED_t; |
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GPS_STATUS_t GpsStatus; |
GPS_POSLLH_t GpsPosLlh; |
GPS_POSUTM_t GpsPosUtm; |
GPS_VELNED_t GpsVelNed; |
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GPS_INFO_t actualPos; |
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void UpdateGPSInfo (void) |
{ |
if (GpsStatus.packetStatus == VALID) // valid packet |
{ |
actualPos.satfix = GpsStatus.GPSfix; |
GpsStatus.packetStatus = PROCESSED; // never update old data |
} |
if (GpsPosLlh.packetStatus == VALID) // valid packet |
{ |
actualPos.longitude = GpsPosLlh.LON; |
actualPos.latitude = GpsPosLlh.LAT; |
actualPos.altitude = GpsPosLlh.HEIGHT; |
GpsPosLlh.packetStatus = PROCESSED; // never update old data |
} |
if (GpsPosUtm.packetStatus == VALID) // valid packet |
{ |
actualPos.utmeast = GpsPosUtm.EAST; |
actualPos.utmnorth = GpsPosUtm.NORTH; |
actualPos.utmalt = GpsPosUtm.ALT; |
GpsPosUtm.packetStatus = PROCESSED; // never update old data |
} |
if (GpsVelNed.packetStatus == VALID) // valid packet |
{ |
actualPos.veleast = GpsVelNed.VEL_E; |
actualPos.velnorth = GpsVelNed.VEL_N; |
actualPos.veltop = -GpsVelNed.VEL_D; |
GpsPosUtm.packetStatus = PROCESSED; // never update old data |
} |
} |
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// this function should be called within the UART RX ISR |
void ubx_parser(uint8_t c) |
{ |
static uint8_t ubxstate = UBXSTATE_IDLE; |
static uint8_t cka, ckb; |
static uint16_t msglen; |
static int8_t *ubxP, *ubxEp, *ubxSp; // pointers to data currently transfered |
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switch(ubxstate) |
{ |
case UBXSTATE_IDLE: // check 1st sync byte |
if (c == UBX_SYNC1_CHAR) ubxstate = UBXSTATE_SYNC1; |
else ubxstate = UBXSTATE_IDLE; // out of synchronization |
break; |
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case UBXSTATE_SYNC1: // check 2nd sync byte |
if (c == UBX_SYNC2_CHAR) ubxstate = UBXSTATE_SYNC2; |
else ubxstate = UBXSTATE_IDLE; // out of synchronization |
break; |
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case UBXSTATE_SYNC2: // check msg class to be NAV |
if (c == UBX_CLASS_NAV) ubxstate = UBXSTATE_CLASS; |
else ubxstate = UBXSTATE_IDLE; // unsupported message class |
break; |
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case UBXSTATE_CLASS: // check message identifier |
switch(c) |
{ |
case UBX_ID_POSUTM: // utm position |
ubxP = (int8_t *)&GpsPosUtm; // data start pointer |
ubxEp = (int8_t *)(&GpsPosUtm + sizeof(GPS_POSUTM_t)); // data end pointer |
ubxSp = (int8_t *)&GpsPosUtm.packetStatus; // status pointer |
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break; |
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case UBX_ID_POSLLH: // geodetic position |
ubxP = (int8_t *)&GpsStatus; // data start pointer |
ubxEp = (int8_t *)(&GpsStatus + sizeof(GPS_STATUS_t)); // data end pointer |
ubxSp = (int8_t *)&GpsStatus.packetStatus; // status pointer |
break; |
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case UBX_ID_STATUS: // receiver status |
ubxP = (int8_t *)&GpsStatus; // data start pointer |
ubxEp = (int8_t *)(&GpsStatus + sizeof(GPS_STATUS_t)); // data end pointer |
ubxSp = (int8_t *)&GpsStatus.packetStatus; // status pointer |
break; |
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case UBX_ID_VELNED: // velocity vector in tangent plane |
ubxP = (int8_t *)&GpsVelNed; // data start pointer |
ubxEp = (int8_t *)(&GpsVelNed + sizeof(GPS_VELNED_t)); // data end pointer |
ubxSp = (int8_t *)&GpsVelNed.packetStatus; // status pointer |
break; |
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default: // unsupported identifier |
ubxstate = UBXSTATE_IDLE; |
break; |
} |
if (ubxstate != UBXSTATE_IDLE) |
{ |
ubxstate = UBXSTATE_LEN1; |
cka = UBX_CLASS_NAV + c; |
ckb = UBX_CLASS_NAV + cka; |
} |
break; |
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case UBXSTATE_LEN1: // 1st message length byte |
msglen = c; |
cka += c; |
ckb += cka; |
ubxstate = UBXSTATE_LEN2; |
break; |
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case UBXSTATE_LEN2: // 2nd message length byte |
msglen += ((uint16_t)c)<<8; |
cka += c; |
ckb += cka; |
// if the old data are not processed so far then break parsing now |
// to avoid writing new data in ISR during reading by another function |
if ( *ubxSp == VALID ) ubxstate = UBXSTATE_IDLE; |
else // data invalid or allready processd |
{ |
*ubxSp = INVALID; |
ubxstate = UBXSTATE_DATA; |
} |
break; |
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case UBXSTATE_DATA: |
if (ubxP < ubxEp) *ubxP++ = c; // copy curent data byte if any space is left |
cka += c; |
ckb += cka; |
if (--msglen == 0) ubxstate = UBXSTATE_CKA; // switch to next state if all data was read |
break; |
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case UBXSTATE_CKA: |
if (c == cka) ubxstate = UBXSTATE_CKB; |
else ubxstate = UBXSTATE_IDLE; |
break; |
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case UBXSTATE_CKB: |
if (c == ckb) |
{ |
*ubxSp = VALID; // new data are availabe |
UpdateGPSInfo(); //update GPS info respectively |
} |
ubxstate = UBXSTATE_IDLE; // ready to parse new data |
break; |
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default: // unknown ubx state |
ubxstate = UBXSTATE_IDLE; |
break; |
} |
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} |
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