most functionality to splashdwon, find neutral and start mission. short timeouts still in code for testing, will adjust to go directly to sit_idle after splashdown
Dependencies: mbed MODSERIAL FATFileSystem
Diff: IMU/IMU.cpp
- Revision:
- 66:0f20870117b7
- Child:
- 74:d281aaef9766
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/IMU/IMU.cpp Tue Jun 19 20:14:23 2018 +0000 @@ -0,0 +1,244 @@ +#include "IMU.h" + +IMU::IMU(PinName Tx, PinName Rx): + _rs232(Tx,Rx) +{ +} + +void IMU::initialize() { + //set up the spi bus and frequency + _rs232.baud(115200); + + // initialize the processing state machine + state = SYNC0; + + // initialize to zeros + euler[0] = 0.0; + euler[1] = 0.0; + euler[2] = 0.0; + + // initialize to zeros + latLonAlt[0] = 0.0; + latLonAlt[1] = 0.0; + latLonAlt[2] = 0.0; + + // initialize to no GNSS fix + is2dFixValid = false; + is3dFixValid = false; + numSV = 0; +} + +// this stops an interval timer trigger of the IMU update function +void IMU::start() { + interval.attach(this, &IMU::update, .05); //this should be a 1 Hz sample rate +} + +// this stops the interval timer trigger of the IMU update function +void IMU::stop() { + interval.detach(); +} + +void IMU::runIMU() { + update(); +} + +// updated the imu update function with a state machine that doesn't hang if no data is present +void IMU::update() { + +// // DEBUGGING an example packet +// Serial pc(USBTX, USBRX); +// //char data[20] = {0x75,0x65,0x80,0x0E,0x0E,0x04,0x3E,0x7A,0x63,0xA0,0xBB,0x8E,0x3B,0x29,0x7F,0xE5,0xBF,0x7F,0x84,0xEE}; // 3d accel +// char data[20] = {0x75,0x65,0x80,0x0E,0x0E,0x0C,0xBA,0xE3,0xED,0x9B,0x3C,0x7D,0x6D,0xDF,0xBF,0x85,0x5C,0xF5,0x41,0xBB}; // euler cf +// for (int j=0; j<20; j++) { + //byte = data[j]; + + while (_rs232.readable()) { + // read a single byte + byte = _rs232.getc(); + + // state machine to process byte-by-byte + switch (state) { + case SYNC0 : + if (byte == 0x75) { + packet[0] = byte; // save into the packet + state = SYNC1; + } + break; + + case SYNC1 : + if (byte == 0x65) { + packet[1] = byte; // save into the packet + state = SET; + } + else { + state = SYNC0; + } + break; + + case SET : + descriptor = byte; // save descriptor set + packet[2] = byte; // save into the packet + state = LEN; + break; + + case LEN : + len = byte; // save payload length + packet[3] = byte; // save into the packet + state = PAY; + i = 0; // reset payload field length counter + break; + + case PAY : + if (i < len) { // keep adding until get all the payload length + packet[4+i] = byte; // add byte to the packet, skipping over the header 4-bytes + i++; // increment payload counter + } + else { + state = CRC0; + } + if (i >= len) { // not an elseif, since we want to escape when i==len + state = CRC0; + } + break; + + case CRC0 : + crc0 = byte; // save the msb of the checksum + state = CRC1; + break; + + case CRC1 : + crc1 = byte; // save the lsb of the checksum + checksum = ((unsigned int)crc0 << 8) + (unsigned int)crc1; // make checksum into a uint16 + if (checksum == calcChecksum(packet, len+4)) { // passed checksum, wahoo! + processPayload(descriptor, packet[4], &packet[4]); // process the payload part of the packet, starting at byte 4 + } + state = SYNC0; // reset to SYNC0 state + break; + + default : + state = SYNC0; + } + } + return; +} + +void IMU::processPayload(char descriptor, char length, unsigned char * payload) { + if (descriptor == IMU_DATA_SET) { // find an IMU data descriptor set + if (length > 2) { // make sure there are at least two bytes to see the field descriptor + if (payload[1] == EULER_CF_DESCRIPTOR) { // find an euler CF field descriptor + processEulerCfPacket(length, payload); + } + } + } + else if (descriptor == GNSS_DATA_SET) { // find a GNSS data descriptor set + if (length > 2) { // make sure there are at least two bytes to see the field descriptor + if (payload[1] == LLH_POSITION_DESCRIPTOR) { // find a lat-lon-alt field descriptor + processLatLonAltPacket(length, payload); + } + else if (payload[1] == GNSS_FIX_INFO_DESCRIPTOR) { // find a gnss fix field descriptor + processGnssFixInformation(length, payload); + } + } + } +} + +void IMU::processEulerCfPacket(char length, unsigned char * payload) { + if (length >= EULER_CF_LENGTH) { // make sure correct field length + if (payload[0] == EULER_CF_LENGTH) { // make sure field length is as expected + euler[0] = floatFromChar(&payload[ROLL_OFFSET+2])*180/_PI; // roll Euler angle convert in degrees + euler[1] = floatFromChar(&payload[PITCH_OFFSET+2])*180/_PI; // pitch Euler angle convert in degrees + euler[2] = floatFromChar(&payload[YAW_OFFSET+2])*180/_PI; // yaw Euler angle convert in degrees + } + } +} + +void IMU::processLatLonAltPacket(char length, unsigned char * payload) { + if (length >= LLH_POSITION_LENGTH) { // make sure correct field length + if (payload[0] == LLH_POSITION_LENGTH) { // make sure field length is as expected + latLonAlt[0] = doubleFromChar(&payload[LATITUDE_OFFSET+2]); // latitude in decimal degrees + latLonAlt[1] = doubleFromChar(&payload[LONGITUDE_OFFSET+2]); // longitude in decimal degrees + latLonAlt[2] = doubleFromChar(&payload[HEIGHT_MSL_OFFSET+2]); // altitude above mean sea level in meters + } + } +} + +void IMU::processGnssFixInformation(char length, unsigned char * payload) { + if (length >= GNSS_FIX_INFO_LENGTH) { // make sure field length is as expected + if (payload[0] == GNSS_FIX_INFO_LENGTH) { // make sure field length is as expected + is2dFixValid = char(payload[FIX_TYPE_OFFSET+2]) & 0x01; // bitand on LSB to see 2d fix flag + is3dFixValid = char(payload[FIX_TYPE_OFFSET+2]) & 0x02; // bitand on LSB to see 3d fix flag + numSV = char(payload[NUM_SV_OFFSET+2]); // number of GNSS satellite vehicles + } + } +} + +float IMU::floatFromChar(unsigned char * value) { + unsigned char temp[4]; + temp[0] = value[3]; + temp[1] = value[2]; + temp[2] = value[1]; + temp[3] = value[0]; + return *(float *) temp; +} + +double IMU::doubleFromChar(unsigned char * value) { + unsigned char temp[8]; + temp[0] = value[7]; + temp[1] = value[6]; + temp[2] = value[5]; + temp[3] = value[4]; + temp[4] = value[3]; + temp[5] = value[2]; + temp[6] = value[1]; + temp[7] = value[0]; + return *(double *) temp; +} + +float IMU::getRoll() { + return euler[0]; +} + +float IMU::getPitch() { + return euler[1]; +} + +float IMU::getHeading() { + return euler[2]; +} + +bool IMU::getIsValid2dFix() { + return is2dFixValid; +} + +bool IMU::getIsValid3dFix() { + return is3dFixValid; +} + +char IMU::getNumSV() { + return numSV; +} + +double IMU::getLatitude() { + return latLonAlt[0]; +} + +double IMU::getLongitude() { + return latLonAlt[1]; +} + +double IMU::getAltitudeMSL() { + return latLonAlt[2]; +} + +unsigned int IMU::calcChecksum(unsigned char * mip_packet, char checksum_range) { + unsigned char checksum_byte1 = 0; + unsigned char checksum_byte2 = 0; + unsigned int myChecksum = 0; + + for (int i=0; i<checksum_range; i++) { + checksum_byte1 += mip_packet[i]; + checksum_byte2 += checksum_byte1; + } + myChecksum = ((unsigned int)checksum_byte1 << 8) + (unsigned int)checksum_byte2; + return myChecksum; +} \ No newline at end of file