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#include <inttypes.h> |
#include "ubx.h" |
#include "main.h" |
#include <avr/io.h> |
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#include "uart.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 |
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#define UBX_ID_POSLLH 0x02 |
#define UBX_ID_SOL 0x06 |
#define UBX_ID_VELNED 0x12 |
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#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 |
int32_t Frac; // ns remainder of rounded ms above |
int16_t week; // GPS week |
uint8_t GPSfix; // GPSfix Type, range 0..6 |
uint8_t Flags; // Navigation Status Flags |
int32_t ECEF_X; // cm ECEF X coordinate |
int32_t ECEF_Y; // cm ECEF Y coordinate |
int32_t ECEF_Z; // cm ECEF Z coordinate |
uint32_t PAcc; // cm 3D Position Accuracy Estimate |
int32_t ECEFVX; // cm/s ECEF X velocity |
int32_t ECEFVY; // cm/s ECEF Y velocity |
int32_t ECEFVZ; // cm/s ECEF Z velocity |
uint32_t SAcc; // cm/s Speed Accuracy Estimate |
uint16_t PDOP; // 0.01 Position DOP |
uint8_t res1; // reserved |
uint8_t numSV; // Number of SVs used in navigation solution |
uint32_t res2; // reserved |
uint8_t Status; |
} GPS_SOL_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 Status; |
} GPS_POSLLH_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 Status; |
} GPS_VELNED_t; |
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GPS_SOL_t GpsSol = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, INVALID}; |
GPS_POSLLH_t GpsPosLlh = {0,0,0,0,0,0,0, INVALID}; |
GPS_VELNED_t GpsVelNed = {0,0,0,0,0,0,0,0,0, INVALID}; |
GPS_INFO_t GPSInfo = {0,0,0,0,0,0,0,0,0,0, INVALID}; |
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volatile uint8_t GPSTimeout = 0; |
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void UpdateGPSInfo (void) |
{ |
static uint32_t lasttime; |
if (GpsSol.Status == VALID) // valid packet |
{ |
GPSInfo.satfix = GpsSol.GPSfix; |
GPSInfo.satnum = GpsSol.numSV; |
GPSInfo.PAcc = GpsSol.PAcc; |
GPSInfo.VAcc = GpsSol.SAcc; |
GpsSol.Status = PROCESSED; // never update old data |
} |
if (GpsPosLlh.Status == VALID) // valid packet |
{ |
GPSInfo.updatetime = GpsPosLlh.ITOW - lasttime; |
lasttime = GpsPosLlh.ITOW; |
GPSInfo.longitude = GpsPosLlh.LON; |
GPSInfo.latitude = GpsPosLlh.LAT; |
GPSInfo.altitude = GpsPosLlh.HEIGHT; |
GpsPosLlh.Status = PROCESSED; // never update old data |
} |
if (GpsVelNed.Status == VALID) // valid packet |
{ |
GPSInfo.veleast = GpsVelNed.VEL_E; |
GPSInfo.velnorth = GpsVelNed.VEL_N; |
GPSInfo.veltop = -GpsVelNed.VEL_D; |
GPSInfo.velground = GpsVelNed.GSpeed; |
GpsVelNed.Status = PROCESSED; // never update old data |
} |
if ((GpsSol.Status != INVALID) && (GpsPosLlh.Status != INVALID) && (GpsVelNed.Status != INVALID)) |
{ |
GPSInfo.status = VALID; // set valid if data are updated |
} |
} |
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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_POSLLH: // geodetic position |
ubxP = (int8_t *)&GpsPosLlh; // data start pointer |
ubxEp = (int8_t *)(&GpsPosLlh + 1); // data end pointer |
ubxSp = (int8_t *)&GpsPosLlh.Status; // status pointer |
break; |
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case UBX_ID_SOL: // navigation solution |
ubxP = (int8_t *)&GpsSol; // data start pointer |
ubxEp = (int8_t *)(&GpsSol + 1); // data end pointer |
ubxSp = (int8_t *)&GpsSol.Status; // 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 + 1); // data end pointer |
ubxSp = (int8_t *)&GpsVelNed.Status; // 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 ) |
{ |
UpdateGPSInfo(); //update GPS info respectively |
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 |
{ |
*ubxSp = INVALID; |
ubxstate = UBXSTATE_IDLE; |
} |
break; |
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case UBXSTATE_CKB: |
if (c == ckb) |
{ |
*ubxSp = VALID; // new data are valid |
ROT_FLASH; |
UpdateGPSInfo(); //update GPS info respectively |
GPSTimeout = 255; |
} |
else |
{ // if checksum not fit then set data invalid |
*ubxSp = INVALID; |
} |
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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