24,9 → 24,9 |
|
// days per month in normal and leap years |
const uint32_t Leap[ 13 ] = { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }; |
const uint32_t Normal[ 13 ] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 }; |
const uint32_t Normal[ 13 ] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 }; |
|
#define LEAP_SECONDS_FROM_1980 15 // the last one was on the Dec 31th 2008 |
#define LEAP_SECONDS_FROM_1980 16 |
|
// message sync bytes |
#define UBX_SYNC1_CHAR 0xB5 |
35,7 → 35,7 |
#define UBX_CLASS_NAV 0x01 |
// message id |
#define UBX_ID_POSLLH 0x02 |
#define UBX_ID_SOL 0x06 |
#define UBX_ID_SOL 0x06 |
#define UBX_ID_VELNED 0x12 |
|
// ------------------------------------------------------------------------------------------------ |
105,8 → 105,6 |
uint8_t Status; // invalid/newdata/processed |
} __attribute__((packed)) ubx_nav_posllh_t; |
|
|
|
//------------------------------------------------------------------------------------ |
// global variables |
|
114,19 → 112,25 |
volatile ubx_nav_sol_t UbxSol = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, INVALID}; |
volatile ubx_nav_posllh_t UbxPosLlh = {0,0,0,0,0,0,0, INVALID}; |
volatile ubx_nav_velned_t UbxVelNed = {0,0,0,0,0,0,0,0,0, INVALID}; |
ubxmsg_t UbxMsg; |
|
uint16_t CheckGPSOkay = 0; |
|
|
// shared buffer |
gps_data_t GPSData = {{0,0,0,INVALID},0,0,0,0,0,0,0, INVALID}; |
gps_data_t GPSData = {200,{0,0,0,INVALID},0,0,0,0,0,0,0, INVALID}; |
DateTime_t GPSDateTime = {0,0,0,0,0,0,0, INVALID}; |
|
#define UBX_TIMEOUT 500 // 500 ms |
uint16_t UBX_Timeout = 0; |
|
|
//------------------------------------------------------------------------------------ |
// functions |
|
uint8_t IsLeapYear(uint16_t year) |
{ |
if((year%400 == 0) || ( (year%4 == 0) && (year%100 != 0) ) ) return 1; |
else return 0; |
if((year%400 == 0) || ( (year%4 == 0) && (year%100 != 0) ) ) return 1; |
else return 0; |
} |
|
/********************************************************/ |
134,74 → 138,72 |
/********************************************************/ |
void SetGPSTime(DateTime_t * pTimeStruct) |
{ |
uint32_t Days, Seconds, Week; |
uint16_t YearPart; |
uint32_t * MonthDayTab = 0; |
uint8_t i; |
uint32_t Days, Seconds, Week; |
uint16_t YearPart; |
uint32_t * MonthDayTab = 0; |
uint8_t i; |
|
|
|
// if GPS data show valid time data |
if((UbxSol.Status != INVALID) && (UbxSol.Flags & FLAG_WKNSET) && (UbxSol.Flags & FLAG_TOWSET) ) |
{ |
Seconds = UbxSol.itow / 1000L; |
Week = (uint32_t)UbxSol.week; |
// correct leap seconds since 1980 |
if(Seconds < LEAP_SECONDS_FROM_1980) |
{ |
Week--; |
Seconds = SECONDS_PER_WEEK - LEAP_SECONDS_FROM_1980 + Seconds; |
} |
else Seconds -= LEAP_SECONDS_FROM_1980; |
// if GPS data show valid time data |
if((UbxSol.Status != INVALID) && (UbxSol.Flags & FLAG_WKNSET) && (UbxSol.Flags & FLAG_TOWSET) ) |
{ |
Seconds = UbxSol.itow / 1000L; |
Week = (uint32_t)UbxSol.week; |
// correct leap seconds since 1980 |
if(Seconds < LEAP_SECONDS_FROM_1980) |
{ |
Week--; |
Seconds = SECONDS_PER_WEEK - LEAP_SECONDS_FROM_1980 + Seconds; |
} |
else Seconds -= LEAP_SECONDS_FROM_1980; |
|
Days = DAYS_FROM_JAN01YEAR0001_TO_JAN6_1980; |
Days += (Week * DAYS_PER_WEEK); |
Days += Seconds / SECONDS_PER_DAY; // seperate days from GPS seconds of week |
Days = DAYS_FROM_JAN01YEAR0001_TO_JAN6_1980; |
Days += (Week * DAYS_PER_WEEK); |
Days += Seconds / SECONDS_PER_DAY; // seperate days from GPS seconds of week |
|
pTimeStruct->Year = 1; |
YearPart = (uint16_t)(Days / DAYS_PER_400YEARS); |
pTimeStruct->Year += YearPart * 400; |
Days = Days % DAYS_PER_400YEARS; |
YearPart = (uint16_t)(Days / DAYS_PER_100YEARS); |
pTimeStruct->Year += YearPart * 100; |
Days = Days % DAYS_PER_100YEARS; |
YearPart = (uint16_t)(Days / DAYS_PER_4YEARS); |
pTimeStruct->Year += YearPart * 4; |
Days = Days % DAYS_PER_4YEARS; |
if(Days < (3* DAYS_PER_YEAR)) YearPart = (uint16_t)(Days / DAYS_PER_YEAR); |
else YearPart = 3; |
pTimeStruct->Year += YearPart; |
// calculate remaining days of year |
Days -= (uint32_t)(YearPart * DAYS_PER_YEAR); |
Days += 1; |
// check if current year is a leap year |
if(IsLeapYear(pTimeStruct->Year)) MonthDayTab = (uint32_t*)Leap; |
else MonthDayTab = (uint32_t*)Normal; |
// seperate month and day from days of year |
for ( i = 0; i < 12; i++ ) |
{ |
if ( (MonthDayTab[i]< Days) && (Days <= MonthDayTab[i+1]) ) |
{ |
pTimeStruct->Month = i+1; |
pTimeStruct->Day = Days - MonthDayTab[i]; |
i = 12; |
} |
} |
Seconds = Seconds % SECONDS_PER_DAY; // remaining seconds of current day |
pTimeStruct->Hour = (uint8_t)(Seconds / SECONDS_PER_HOUR); |
Seconds = Seconds % SECONDS_PER_HOUR; // remaining seconds of current hour |
pTimeStruct->Min = (uint8_t)(Seconds / SECONDS_PER_MINUTE); |
Seconds = Seconds % SECONDS_PER_MINUTE; // remaining seconds of current minute |
pTimeStruct->Sec = (uint8_t)(Seconds); |
pTimeStruct->mSec = (uint16_t)(UbxSol.itow % 1000L); |
pTimeStruct->Valid = 1; |
} |
else |
{ |
pTimeStruct->Valid = 0; |
} |
DebugOut.Analog[0]++; |
|
pTimeStruct->Year = 1; |
YearPart = (uint16_t)(Days / DAYS_PER_400YEARS); |
pTimeStruct->Year += YearPart * 400; |
Days = Days % DAYS_PER_400YEARS; |
YearPart = (uint16_t)(Days / DAYS_PER_100YEARS); |
pTimeStruct->Year += YearPart * 100; |
Days = Days % DAYS_PER_100YEARS; |
YearPart = (uint16_t)(Days / DAYS_PER_4YEARS); |
pTimeStruct->Year += YearPart * 4; |
Days = Days % DAYS_PER_4YEARS; |
if(Days < (3* DAYS_PER_YEAR)) YearPart = (uint16_t)(Days / DAYS_PER_YEAR); |
else YearPart = 3; |
pTimeStruct->Year += YearPart; |
// calculate remaining days of year |
Days -= (uint32_t)(YearPart * DAYS_PER_YEAR); |
Days += 1; |
// check if current year is a leap year |
if(IsLeapYear(pTimeStruct->Year)) MonthDayTab = (uint32_t*)Leap; |
else MonthDayTab = (uint32_t*)Normal; |
// seperate month and day from days of year |
for ( i = 0; i < 12; i++ ) |
{ |
if ( (MonthDayTab[i]< Days) && (Days <= MonthDayTab[i+1]) ) |
{ |
pTimeStruct->Month = i+1; |
pTimeStruct->Day = Days - MonthDayTab[i]; |
i = 12; |
} |
} |
Seconds = Seconds % SECONDS_PER_DAY; // remaining seconds of current day |
pTimeStruct->Hour = (uint8_t)(Seconds / SECONDS_PER_HOUR); |
Seconds = Seconds % SECONDS_PER_HOUR; // remaining seconds of current hour |
pTimeStruct->Min = (uint8_t)(Seconds / SECONDS_PER_MINUTE); |
Seconds = Seconds % SECONDS_PER_MINUTE; // remaining seconds of current minute |
pTimeStruct->Sec = (uint8_t)(Seconds); |
pTimeStruct->mSec = (uint16_t)(UbxSol.itow % 1000L); |
pTimeStruct->Valid = 1; |
} |
else |
{ |
pTimeStruct->Valid = 0; |
} |
} |
|
|
211,209 → 213,243 |
/********************************************************/ |
void UBX_Init(void) |
{ |
// mark msg buffers invalid |
UbxSol.Status = INVALID; |
UbxPosLlh.Status = INVALID; |
UbxVelNed.Status = INVALID; |
GPSData.Status = INVALID; |
// mark msg buffers invalid |
UbxSol.Status = INVALID; |
UbxPosLlh.Status = INVALID; |
UbxVelNed.Status = INVALID; |
UbxMsg.Status = INVALID; |
GPSData.Status = INVALID; |
|
UBX_Setup(); |
|
UBX_Timeout = SetDelay(2 * UBX_Timeout); |
} |
|
/********************************************************/ |
/* Upate GPS data stcructure */ |
/********************************************************/ |
void Update_GPSData (void) |
void Update_GPSData(void) |
{ |
static uint16_t Ubx_Timeout = 0; |
static uint8_t Msg_Count = 0; |
static uint32_t last_itow = 0; |
|
// the timeout is used to detect the delay between two message sets |
// and is used for synchronisation so that always a set is collected |
// that belongs together |
// _______NAVSOL|POSLLH|VELNED|___________________NAVSOL|POSLLH|VELNED|_____________ |
// | 8ms | 8ms | 184 ms | | | |
// msg_count: 0 1 2 0 1 2 |
|
if(CheckDelay(Ubx_Timeout)) Msg_Count = 0; |
else Msg_Count++; |
Ubx_Timeout = SetDelay(100); // reset ubx msg timeout |
// if a new set of ubx messages was collected |
if((UbxSol.Status == NEWDATA) && (UbxPosLlh.Status == NEWDATA) && (UbxVelNed.Status == NEWDATA)) |
{ // and the itow is equal (same time base) |
if((UbxSol.itow == UbxPosLlh.itow) && (UbxPosLlh.itow == UbxVelNed.itow)) |
{ |
UBX_Timeout = SetDelay(UBX_TIMEOUT); |
DebugOut.Analog[11]++; |
// update GPS data only if the status is INVALID or PROCESSED |
if(GPSData.Status != NEWDATA) |
{ // wait for new data at all neccesary ubx messages |
GPSData.Status = INVALID; |
// update message cycle time |
GPSData.MsgCycleTime = (uint16_t)(UbxSol.itow-last_itow); |
last_itow = UbxSol.itow; // update last itow |
// NAV SOL |
GPSData.Flags = (GPSData.Flags & 0xf0) | (UbxSol.Flags & 0x0f); // we take only the lower bits |
GPSData.NumOfSats = UbxSol.numSV; |
GPSData.SatFix = UbxSol.GPSfix; |
GPSData.Position_Accuracy = UbxSol.PAcc; // in steps of 1cm |
GPSData.Speed_Accuracy = UbxSol.SAcc; // in steps of 1cm/s |
SetGPSTime(&SystemTime); // update system time |
// NAV POSLLH |
GPSData.Position.Status = INVALID; |
GPSData.Position.Longitude = UbxPosLlh.LON; // in steps of 1E-7 deg |
GPSData.Position.Latitude = UbxPosLlh.LAT; // in steps of 1E-7 deg |
GPSData.Position.Altitude = UbxPosLlh.HMSL; // in steps of 1 mm |
GPSData.Position.Status = NEWDATA; |
// NAV VELNED |
GPSData.Speed_East = UbxVelNed.VEL_E; // in steps of 1cm/s |
GPSData.Speed_North = UbxVelNed.VEL_N; // in steps of 1cm/s |
GPSData.Speed_Top = -UbxVelNed.VEL_D; // in steps of 1cm/s |
GPSData.Speed_Ground = UbxVelNed.GSpeed; // in steps of 1cm/s |
GPSData.Heading = UbxVelNed.Heading; //in steps of 1E-5 deg |
|
// if a new set of ubx messages was collected |
if((Msg_Count >= 2)) |
{ // if set is complete |
if((UbxSol.Status == NEWDATA) && (UbxPosLlh.Status == NEWDATA) && (UbxVelNed.Status == NEWDATA)) |
{ |
CheckGPSOkay++; |
CountNewGpsDataIn5Sec++; |
// update GPS data only if the status is INVALID or PROCESSED and the last ubx message was received within less than 100 ms |
if(GPSData.Status != NEWDATA) // if last data were processed |
{ // wait for new data at all neccesary ubx messages |
GPSData.Status = INVALID; |
// NAV SOL |
GPSData.Flags = UbxSol.Flags; |
GPSData.NumOfSats = UbxSol.numSV; |
GPSData.SatFix = UbxSol.GPSfix; |
GPSData.Position_Accuracy = UbxSol.PAcc; |
GPSData.Speed_Accuracy = UbxSol.SAcc; |
SetGPSTime(&SystemTime); // update system time |
// NAV POSLLH |
GPSData.Position.Status = INVALID; |
GPSData.Position.Longitude = UbxPosLlh.LON; |
GPSData.Position.Latitude = UbxPosLlh.LAT; |
GPSData.Position.Altitude = UbxPosLlh.HMSL; |
GPSData.Position.Status = NEWDATA; |
// NAV VELNED |
GPSData.Speed_East = UbxVelNed.VEL_E; |
GPSData.Speed_North = UbxVelNed.VEL_N; |
GPSData.Speed_Top = -UbxVelNed.VEL_D; |
GPSData.Speed_Ground = UbxVelNed.GSpeed; |
GPSData.Heading = UbxVelNed.Heading; |
|
GPSData.Status = NEWDATA; // new data available |
|
GPSData.Status = PROCESSED; // TODO: |
} // EOF if(GPSData.Status != NEWDATA) |
} // EOF all ubx messages received |
// set state to collect new data |
UbxSol.Status = PROCESSED; // ready for new data |
UbxPosLlh.Status = PROCESSED; // ready for new data |
UbxVelNed.Status = PROCESSED; // ready for new data |
} |
GPSData.Status = NEWDATA; // new data available |
} // EOF if(GPSData.Status != NEWDATA) |
// set state to collect new data |
UbxSol.Status = PROCESSED; // ready for new data |
UbxPosLlh.Status = PROCESSED; // ready for new data |
UbxVelNed.Status = PROCESSED; // ready for new data |
} // EOF all itow are equal |
} // EOF all ubx messages received |
} |
|
|
/********************************************************/ |
/* UBX Parser */ |
/********************************************************/ |
void UBX_Parser(uint8_t c) |
{ |
static ubxState_t ubxState = UBXSTATE_IDLE; |
static uint16_t msglen; |
static uint8_t cka, ckb; |
static uint8_t *ubxP, *ubxEp, *ubxSp; // pointers to data currently transfered |
static ubxState_t ubxState = UBXSTATE_IDLE; |
static ubxmsghdr_t RxHdr; |
static uint8_t RxData[UBX_MSG_DATA_SIZE]; |
static uint16_t RxBytes = 0; |
static uint8_t cka, ckb; |
|
|
//state machine |
switch (ubxState) // ubx message parser |
{ |
case UBXSTATE_IDLE: // check 1st sync byte |
if (c == UBX_SYNC1_CHAR) ubxState = UBXSTATE_SYNC1; |
else ubxState = UBXSTATE_IDLE; // out of synchronization |
break; |
//state machine |
switch (ubxState) // ubx message parser |
{ |
case UBXSTATE_IDLE: // check 1st sync byte |
if (c == UBX_SYNC1_CHAR) ubxState = UBXSTATE_SYNC1; |
else ubxState = UBXSTATE_IDLE; // out of synchronization |
break; |
|
case UBXSTATE_SYNC1: // check 2nd sync byte |
if (c == UBX_SYNC2_CHAR) ubxState = UBXSTATE_SYNC2; |
else ubxState = UBXSTATE_IDLE; // out of synchronization |
break; |
case UBXSTATE_SYNC1: // check 2nd sync byte |
if (c == UBX_SYNC2_CHAR) ubxState = UBXSTATE_SYNC2; |
else ubxState = UBXSTATE_IDLE; // out of synchronization |
break; |
|
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; |
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; |
|
case UBXSTATE_CLASS: // check message identifier |
switch(c) |
{ |
case UBX_ID_POSLLH: // geodetic position |
ubxP = (uint8_t *)&UbxPosLlh; // data start pointer |
ubxEp = (uint8_t *)(&UbxPosLlh + 1); // data end pointer |
ubxSp = (uint8_t *)&UbxPosLlh.Status; // status pointer |
break; |
case UBXSTATE_CLASS: // check message identifier |
RxHdr.Id = c; |
ubxState = UBXSTATE_LEN1; |
cka = RxHdr.Class + RxHdr.Id; |
ckb = RxHdr.Class + cka; |
break; |
|
case UBX_ID_SOL: // navigation solution |
ubxP = (uint8_t *)&UbxSol; // data start pointer |
ubxEp = (uint8_t *)(&UbxSol + 1); // data end pointer |
ubxSp = (uint8_t *)&UbxSol.Status; // status pointer |
break; |
case UBXSTATE_LEN1: // 1st message length byte |
RxHdr.Length = (uint16_t)c; // lowbyte first |
cka += c; |
ckb += cka; |
ubxState = UBXSTATE_LEN2; |
break; |
|
case UBX_ID_VELNED: // velocity vector in tangent plane |
ubxP = (uint8_t *)&UbxVelNed; // data start pointer |
ubxEp = (uint8_t *)(&UbxVelNed + 1); // data end pointer |
ubxSp = (uint8_t *)&UbxVelNed.Status; // status pointer |
break; |
case UBXSTATE_LEN2: // 2nd message length byte |
RxHdr.Length += ((uint16_t)c)<<8; // high byte last |
if (RxHdr.Length >= UBX_MSG_DATA_SIZE) |
{ |
ubxState = UBXSTATE_IDLE; |
} |
else |
{ |
cka += c; |
ckb += cka; |
RxBytes = 0; // reset data byte counter |
ubxState = UBXSTATE_DATA; |
} |
break; |
|
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; |
case UBXSTATE_DATA: // collecting data |
if (RxBytes < UBX_MSG_DATA_SIZE) |
{ |
RxData[RxBytes++] = c; // copy curent data byte if any space is left |
cka += c; |
ckb += cka; |
if (RxBytes >= RxHdr.Length) ubxState = UBXSTATE_CKA; // switch to next state if all data have been received |
} |
else // rx buffer overrun |
{ |
ubxState = UBXSTATE_IDLE; |
} |
break; |
|
case UBXSTATE_LEN1: // 1st message length byte |
msglen = (uint16_t)c; // lowbyte first |
cka += c; |
ckb += cka; |
ubxState = UBXSTATE_LEN2; |
break; |
|
case UBXSTATE_LEN2: // 2nd message length byte |
msglen += ((uint16_t)c)<<8; // high byte last |
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 == NEWDATA ) |
{ |
ubxState = UBXSTATE_IDLE; |
Update_GPSData(); //update GPS info respectively |
} |
else // data invalid or allready processd |
{ |
*ubxSp = INVALID; // mark invalid during buffer filling |
ubxState = UBXSTATE_DATA; |
} |
break; |
case UBXSTATE_CKA: |
if (c == cka) ubxState = UBXSTATE_CKB; |
else |
{ |
ubxState = UBXSTATE_IDLE; |
} |
break; |
|
case UBXSTATE_DATA: // collecting 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 |
} |
else // rx buffer overrun |
{ |
ubxState = UBXSTATE_IDLE; |
} |
break; |
case UBXSTATE_CKB: |
if (c == ckb) |
{ // checksum is ok |
|
case UBXSTATE_CKA: |
if (c == cka) ubxState = UBXSTATE_CKB; |
else |
{ |
*ubxSp = INVALID; |
ubxState = UBXSTATE_IDLE; |
} |
break; |
switch(RxHdr.Class) |
{ |
case UBX_CLASS_NAV: |
switch(RxHdr.Id) |
{ |
case UBX_ID_POSLLH: // geodetic position |
memcpy((uint8_t*)&UbxPosLlh, RxData, RxHdr.Length); |
UbxPosLlh.Status = NEWDATA; |
break; |
|
case UBXSTATE_CKB: |
if (c == ckb) |
{ |
*ubxSp = NEWDATA; // new data are valid |
Update_GPSData(); //update GPS info respectively |
} |
else |
{ // if checksum not match then set data invalid |
*ubxSp = INVALID; |
} |
ubxState = UBXSTATE_IDLE; // ready to parse new data |
break; |
case UBX_ID_VELNED: // velocity vector in tangent plane |
memcpy((uint8_t*)&UbxVelNed, RxData, RxHdr.Length); |
UbxVelNed.Status = NEWDATA; |
break; |
|
default: // unknown ubx state |
ubxState = UBXSTATE_IDLE; |
break; |
case UBX_ID_SOL: // navigation solution |
memcpy((uint8_t*)&UbxSol, RxData, RxHdr.Length); |
UbxSol.Status = NEWDATA; |
break; |
|
} |
DebugOut.Analog[6] = GPSData.NumOfSats; |
/* DebugOut.Analog[10] = GPSData.Speed_East; |
DebugOut.Analog[9] = GPSData.Speed_North; |
DebugOut.Analog[11] = GPSData.Speed_Top; |
DebugOut.Analog[13] = GPSData.Position.Longitude; |
DebugOut.Analog[14] = GPSData.Position.Latitude; |
DebugOut.Analog[15] = GPSData.Position.Altitude;*/ |
default: |
break; |
} // EOF switch(Id) |
Update_GPSData(); |
break; |
|
default: // any other class |
break; |
} // EOF switch(class) |
|
// check generic msg filter |
if(UbxMsg.Status != NEWDATA) |
{ // msg buffer is free |
if(((UbxMsg.Hdr.Class & UbxMsg.ClassMask) == (RxHdr.Class & UbxMsg.ClassMask)) && ((UbxMsg.Hdr.Id & UbxMsg.IdMask) == (RxHdr.Id & UbxMsg.IdMask))) |
{ // msg matches to the filter criteria |
UbxMsg.Status = INVALID; |
UbxMsg.Hdr.Class = RxHdr.Class; |
UbxMsg.Hdr.Id = RxHdr.Id; |
UbxMsg.Hdr.Length = RxHdr.Length; |
if(UbxMsg.Hdr.Length <= UBX_MSG_DATA_SIZE) |
{ // copy data block |
memcpy(UbxMsg.Data, RxData, RxHdr.Length); |
UbxMsg.Status = NEWDATA; |
} |
} // EOF filter matches |
} // EOF != INVALID |
}// EOF crc ok |
ubxState = UBXSTATE_IDLE; // ready to parse new data |
break; |
|
default: // unknown ubx state |
ubxState = UBXSTATE_IDLE; |
break; |
|
} |
} |
|
/**************************************************************/ |
/* Create a UBX Message */ |
/**************************************************************/ |
uint8_t UBX_CreateMsg(Buffer_t* pBuff, uint8_t* pData, uint16_t Len) |
{ |
uint16_t i; |
uint8_t cka = 0, ckb = 0; |
// check if buffer is available |
if(pBuff->Locked) return(0); |
// check if buffer size is sufficient |
if(pBuff->Size < 8 + Len) return(0); |
// lock the buffer |
pBuff->Locked = 1; |
// start at begin |
pBuff->Position = 0; |
pBuff->pData[pBuff->Position++] = UBX_SYNC1_CHAR; |
pBuff->pData[pBuff->Position++] = UBX_SYNC2_CHAR; |
for(i=0;i<Len;i++) |
{ |
pBuff->pData[pBuff->Position++] = pData[i]; |
} |
// calculate checksum |
for(i=2;i<pBuff->Position;i++) |
{ |
cka += pBuff->pData[i]; |
ckb += cka; |
} |
pBuff->pData[pBuff->Position++] = cka; |
pBuff->pData[pBuff->Position++] = ckb; |
pBuff->DataBytes = pBuff->Position; |
pBuff->Position = 0; // reset buffer position for transmision |
return(1); |
} |
|