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IMUProtocol.h
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/* ============================================
Nav6 source code is placed under the MIT license
Copyright (c) 2013 Kauai Labs
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
===============================================
*/
#ifndef _IMU_PROTOCOL_H_
#define _IMU_PROTOCOL_H_
#define PACKET_START_CHAR '!'
#define CHECKSUM_LENGTH 2 /* 8-bit checksump, all bytes before checksum */
#define TERMINATOR_LENGTH 2 /* Carriage Return, Line Feed */
#define PROTOCOL_FLOAT_LENGTH 7
// Yaw/Pitch/Roll (YPR) Update Packet - e.g., !y[yaw][pitch][roll][compass]
// (All values as floats)
#define MSGID_YPR_UPDATE 'y'
#define YPR_UPDATE_YAW_VALUE_INDEX 2
#define YPR_UPDATE_ROLL_VALUE_INDEX 9
#define YPR_UPDATE_PITCH_VALUE_INDEX 16
#define YPR_UPDATE_COMPASS_VALUE_INDEX 23
#define YPR_UPDATE_CHECKSUM_INDEX 30
#define YPR_UPDATE_TERMINATOR_INDEX 32
#define YPR_UPDATE_MESSAGE_LENGTH 34
// Quaternion Update Packet - e.g., !r[q1][q2][q3][q4][accelx][accely][accelz][magx][magy][magz]
#define MSGID_QUATERNION_UPDATE 'q'
#define QUATERNION_UPDATE_QUAT1_VALUE_INDEX 2
#define QUATERNION_UPDATE_QUAT2_VALUE_INDEX 6
#define QUATERNION_UPDATE_QUAT3_VALUE_INDEX 10
#define QUATERNION_UPDATE_QUAT4_VALUE_INDEX 14
#define QUATERNION_UPDATE_ACCEL_X_VALUE_INDEX 18
#define QUATERNION_UPDATE_ACCEL_Y_VALUE_INDEX 22
#define QUATERNION_UPDATE_ACCEL_Z_VALUE_INDEX 26
#define QUATERNION_UPDATE_MAG_X_VALUE_INDEX 30
#define QUATERNION_UPDATE_MAG_Y_VALUE_INDEX 34
#define QUATERNION_UPDATE_MAG_Z_VALUE_INDEX 38
#define QUATERNION_UPDATE_TEMP_VALUE_INDEX 42
#define QUATERNION_UPDATE_CHECKSUM_INDEX 49
#define QUATERNION_UPDATE_TERMINATOR_INDEX 51
#define QUATERNION_UPDATE_MESSAGE_LENGTH 53
// Gyro/Raw Data Update packet - e.g., !g[gx][gy][gz][accelx][accely][accelz][magx][magy][magz][temp_c]
#define MSGID_GYRO_UPDATE 'g'
#define GYRO_UPDATE_MESSAGE_LENGTH 46
#define GYRO_UPDATE_GYRO_X_VALUE_INDEX 2
#define GYRO_UPDATE_GYRO_Y_VALUE_INDEX 6
#define GYRO_UPDATE_GYRO_Z_VALUE_INDEX 10
#define GYRO_UPDATE_ACCEL_X_VALUE_INDEX 14
#define GYRO_UPDATE_ACCEL_Y_VALUE_INDEX 18
#define GYRO_UPDATE_ACCEL_Z_VALUE_INDEX 22
#define GYRO_UPDATE_MAG_X_VALUE_INDEX 26
#define GYRO_UPDATE_MAG_Y_VALUE_INDEX 30
#define GYRO_UPDATE_MAG_Z_VALUE_INDEX 34
#define GYRO_UPDATE_TEMP_VALUE_INDEX 38
#define GYRO_UPDATE_CHECKSUM_INDEX 42
#define GYRO_UPDATE_TERMINATOR_INDEX 44
// EnableStream Command Packet - e.g., !S[stream type]
#define MSGID_STREAM_CMD 'S'
#define STREAM_CMD_STREAM_TYPE_YPR MSGID_YPR_UPDATE
#define STREAM_CMD_STREAM_TYPE_QUATERNION MSGID_QUATERNION_UPDATE
#define STREAM_CMD_STREAM_TYPE_RAW MSGID_RAW_UPDATE
#define STREAM_CMD_STREAM_TYPE_INDEX 2
#define STREAM_CMD_UPDATE_RATE_HZ_INDEX 3
#define STREAM_CMD_CHECKSUM_INDEX 5
#define STREAM_CMD_TERMINATOR_INDEX 7
#define STREAM_CMD_MESSAGE_LENGTH 9
// EnableStream Response Packet - e.g., !s[stream type][gyro full scale range][accel full scale range][update rate hz][yaw_offset_degrees][q1/2/3/4 offsets][flags][checksum][cr][lf]
#define MSG_ID_STREAM_RESPONSE 's'
#define STREAM_RESPONSE_STREAM_TYPE_INDEX 2
#define STREAM_RESPONSE_GYRO_FULL_SCALE_DPS_RANGE 3
#define STREAM_RESPONSE_ACCEL_FULL_SCALE_G_RANGE 7
#define STREAM_RESPONSE_UPDATE_RATE_HZ 11
#define STREAM_RESPONSE_YAW_OFFSET_DEGREES 15
#define STREAM_RESPONSE_QUAT1_OFFSET 22 /* Deprecated */
#define STREAM_RESPONSE_QUAT2_OFFSET 26 /* Deprecated */
#define STREAM_RESPONSE_QUAT3_OFFSET 30 /* Deprecated */
#define STREAM_RESPONSE_QUAT4_OFFSET 34 /* Deprecated */
#define STREAM_RESPONSE_FLAGS 38
#define STREAM_RESPONSE_CHECKSUM_INDEX 42
#define STREAM_RESPONSE_TERMINATOR_INDEX 44
#define STREAM_RESPONSE_MESSAGE_LENGTH 46
#define NAV6_FLAG_MASK_CALIBRATION_STATE 0x03
#define NAV6_CALIBRATION_STATE_WAIT 0x00
#define NAV6_CALIBRATION_STATE_ACCUMULATE 0x01
#define NAV6_CALIBRATION_STATE_COMPLETE 0x02
#include <stdio.h>
#include <stdlib.h>
#define IMU_PROTOCOL_MAX_MESSAGE_LENGTH QUATERNION_UPDATE_MESSAGE_LENGTH
class IMUProtocol
{
public:
struct YPRUpdate {
float yaw;
float pitch;
float roll;
float compass_heading;
};
struct GyroUpdate {
int16_t gyro_x;
int16_t gyro_y;
int16_t gyro_z;
int16_t accel_x;
int16_t accel_y;
int16_t accel_z;
int16_t mag_x;
int16_t mag_y;
int16_t mag_z;
float temp_c;
};
struct QuaternionUpdate {
int16_t q1;
int16_t q2;
int16_t q3;
int16_t q4;
int16_t accel_x;
int16_t accel_y;
int16_t accel_z;
int16_t mag_x;
int16_t mag_y;
int16_t mag_z;
float temp_c;
};
struct StreamResponse {
uint8_t stream_type;
int16_t gyro_fsr_dps;
int16_t accel_fsr_g;
int16_t update_rate_hz;
float yaw_offset_degrees;
int16_t q1_offset;
int16_t q2_offset;
int16_t q3_offset;
int16_t q4_offset;
int16_t flags;
};
public:
static int encodeYPRUpdate( char *protocol_buffer, float yaw, float pitch, float roll, float compass_heading )
{
// Header
protocol_buffer[0] = PACKET_START_CHAR;
protocol_buffer[1] = MSGID_YPR_UPDATE;
// Data
encodeProtocolFloat( yaw, &protocol_buffer[YPR_UPDATE_YAW_VALUE_INDEX] );
encodeProtocolFloat( pitch, &protocol_buffer[YPR_UPDATE_PITCH_VALUE_INDEX] );
encodeProtocolFloat( roll, &protocol_buffer[YPR_UPDATE_ROLL_VALUE_INDEX] );
encodeProtocolFloat( compass_heading, &protocol_buffer[YPR_UPDATE_COMPASS_VALUE_INDEX] );
// Footer
encodeTermination( protocol_buffer, YPR_UPDATE_MESSAGE_LENGTH, YPR_UPDATE_MESSAGE_LENGTH - 4 );
return YPR_UPDATE_MESSAGE_LENGTH;
}
static int encodeQuaternionUpdate( char *protocol_buffer,
uint16_t q1, uint16_t q2, uint16_t q3, uint16_t q4,
uint16_t accel_x, uint16_t accel_y, uint16_t accel_z,
int16_t mag_x, int16_t mag_y, int16_t mag_z,
float temp_c )
{
// Header
protocol_buffer[0] = PACKET_START_CHAR;
protocol_buffer[1] = MSGID_QUATERNION_UPDATE;
// Data
encodeProtocolUint16( q1, &protocol_buffer[QUATERNION_UPDATE_QUAT1_VALUE_INDEX] );
encodeProtocolUint16( q2, &protocol_buffer[QUATERNION_UPDATE_QUAT2_VALUE_INDEX] );
encodeProtocolUint16( q3, &protocol_buffer[QUATERNION_UPDATE_QUAT3_VALUE_INDEX] );
encodeProtocolUint16( q4, &protocol_buffer[QUATERNION_UPDATE_QUAT4_VALUE_INDEX] );
encodeProtocolUint16( accel_x, &protocol_buffer[QUATERNION_UPDATE_ACCEL_X_VALUE_INDEX] );
encodeProtocolUint16( accel_y, &protocol_buffer[QUATERNION_UPDATE_ACCEL_Y_VALUE_INDEX] );
encodeProtocolUint16( accel_z, &protocol_buffer[QUATERNION_UPDATE_ACCEL_Z_VALUE_INDEX] );
encodeProtocolUint16( (uint16_t)mag_x, &protocol_buffer[QUATERNION_UPDATE_MAG_X_VALUE_INDEX] );
encodeProtocolUint16( (uint16_t)mag_y, &protocol_buffer[QUATERNION_UPDATE_MAG_Y_VALUE_INDEX] );
encodeProtocolUint16( (uint16_t)mag_z, &protocol_buffer[QUATERNION_UPDATE_MAG_Z_VALUE_INDEX] );
encodeProtocolFloat( temp_c, &protocol_buffer[QUATERNION_UPDATE_TEMP_VALUE_INDEX] );
// Footer
encodeTermination( protocol_buffer, QUATERNION_UPDATE_MESSAGE_LENGTH, QUATERNION_UPDATE_MESSAGE_LENGTH - 4 );
return QUATERNION_UPDATE_MESSAGE_LENGTH;
}
static int encodeGyroUpdate( char *protocol_buffer,
uint16_t gyro_x, uint16_t gyro_y, uint16_t gyro_z,
uint16_t accel_x, uint16_t accel_y, uint16_t accel_z,
int16_t mag_x, int16_t mag_y, int16_t mag_z,
float temp_c )
{
// Header
protocol_buffer[0] = PACKET_START_CHAR;
protocol_buffer[1] = MSGID_GYRO_UPDATE;
// Data
encodeProtocolUint16( gyro_x, &protocol_buffer[GYRO_UPDATE_GYRO_X_VALUE_INDEX] );
encodeProtocolUint16( gyro_y, &protocol_buffer[GYRO_UPDATE_GYRO_Y_VALUE_INDEX] );
encodeProtocolUint16( gyro_z, &protocol_buffer[GYRO_UPDATE_GYRO_Z_VALUE_INDEX] );
encodeProtocolUint16( accel_x, &protocol_buffer[GYRO_UPDATE_ACCEL_X_VALUE_INDEX] );
encodeProtocolUint16( accel_y, &protocol_buffer[GYRO_UPDATE_ACCEL_Y_VALUE_INDEX] );
encodeProtocolUint16( accel_z, &protocol_buffer[GYRO_UPDATE_ACCEL_Z_VALUE_INDEX] );
encodeProtocolUint16( (uint16_t)mag_x, &protocol_buffer[GYRO_UPDATE_MAG_X_VALUE_INDEX] );
encodeProtocolUint16( (uint16_t)mag_y, &protocol_buffer[GYRO_UPDATE_MAG_Y_VALUE_INDEX] );
encodeProtocolUint16( (uint16_t)mag_z, &protocol_buffer[GYRO_UPDATE_MAG_Z_VALUE_INDEX] );
encodeProtocolUnsignedHundredthsFloat( temp_c, &protocol_buffer[GYRO_UPDATE_TEMP_VALUE_INDEX] );
// Footer
encodeTermination( protocol_buffer, GYRO_UPDATE_MESSAGE_LENGTH, GYRO_UPDATE_MESSAGE_LENGTH - 4 );
return GYRO_UPDATE_MESSAGE_LENGTH;
}
static int encodeStreamCommand( char *protocol_buffer, char stream_type, unsigned char update_rate_hz)
{
// Header
protocol_buffer[0] = PACKET_START_CHAR;
protocol_buffer[1] = MSGID_STREAM_CMD;
// Data
protocol_buffer[STREAM_CMD_STREAM_TYPE_INDEX] = stream_type;
// convert update_rate_hz to two ascii bytes
sprintf(&protocol_buffer[STREAM_CMD_UPDATE_RATE_HZ_INDEX], "%02X", update_rate_hz);
// Footer
encodeTermination( protocol_buffer, STREAM_CMD_MESSAGE_LENGTH, STREAM_CMD_MESSAGE_LENGTH - 4 );
return STREAM_CMD_MESSAGE_LENGTH;
}
static int encodeStreamResponse( char *protocol_buffer, char stream_type,
uint16_t gyro_fsr_dps, uint16_t accel_fsr_g, uint16_t update_rate_hz,
float yaw_offset_degrees,
uint16_t q1_offset, uint16_t q2_offset, uint16_t q3_offset, uint16_t q4_offset,
uint16_t flags)
{
// Header
protocol_buffer[0] = PACKET_START_CHAR;
protocol_buffer[1] = MSG_ID_STREAM_RESPONSE;
// Data
protocol_buffer[STREAM_RESPONSE_STREAM_TYPE_INDEX] = stream_type;
encodeProtocolUint16( gyro_fsr_dps, &protocol_buffer[STREAM_RESPONSE_GYRO_FULL_SCALE_DPS_RANGE] );
encodeProtocolUint16( accel_fsr_g, &protocol_buffer[STREAM_RESPONSE_ACCEL_FULL_SCALE_G_RANGE] );
encodeProtocolUint16( update_rate_hz, &protocol_buffer[STREAM_RESPONSE_UPDATE_RATE_HZ] );
encodeProtocolFloat( yaw_offset_degrees, &protocol_buffer[STREAM_RESPONSE_YAW_OFFSET_DEGREES] );
encodeProtocolUint16( q1_offset, &protocol_buffer[STREAM_RESPONSE_QUAT1_OFFSET]);
encodeProtocolUint16( q2_offset, &protocol_buffer[STREAM_RESPONSE_QUAT2_OFFSET]);
encodeProtocolUint16( q3_offset, &protocol_buffer[STREAM_RESPONSE_QUAT3_OFFSET]);
encodeProtocolUint16( q4_offset, &protocol_buffer[STREAM_RESPONSE_QUAT4_OFFSET]);
encodeProtocolUint16( flags, &protocol_buffer[STREAM_RESPONSE_FLAGS] );
// Footer
encodeTermination( protocol_buffer, STREAM_RESPONSE_MESSAGE_LENGTH, STREAM_RESPONSE_MESSAGE_LENGTH - 4 );
return STREAM_RESPONSE_MESSAGE_LENGTH;
}
static int decodeStreamResponse( char *buffer, int length, struct StreamResponse& rsp )
{
if ( length < STREAM_RESPONSE_MESSAGE_LENGTH ) return 0;
if ( ( buffer[0] == PACKET_START_CHAR ) && ( buffer[1] == MSG_ID_STREAM_RESPONSE ) )
{
if ( !verifyChecksum( buffer, STREAM_RESPONSE_CHECKSUM_INDEX ) ) return 0;
rsp.stream_type = buffer[2];
rsp.gyro_fsr_dps = decodeProtocolUint16( &buffer[STREAM_RESPONSE_GYRO_FULL_SCALE_DPS_RANGE] );
rsp.accel_fsr_g = decodeProtocolUint16( &buffer[STREAM_RESPONSE_ACCEL_FULL_SCALE_G_RANGE] );
rsp.update_rate_hz = decodeProtocolUint16( &buffer[STREAM_RESPONSE_UPDATE_RATE_HZ] );
rsp.yaw_offset_degrees = decodeProtocolFloat( &buffer[STREAM_RESPONSE_YAW_OFFSET_DEGREES] );
rsp.q1_offset = decodeProtocolUint16( &buffer[STREAM_RESPONSE_QUAT1_OFFSET]);
rsp.q2_offset = decodeProtocolUint16( &buffer[STREAM_RESPONSE_QUAT2_OFFSET]);
rsp.q3_offset = decodeProtocolUint16( &buffer[STREAM_RESPONSE_QUAT3_OFFSET]);
rsp.q4_offset = decodeProtocolUint16( &buffer[STREAM_RESPONSE_QUAT4_OFFSET]);
rsp.flags = decodeProtocolUint16( &buffer[STREAM_RESPONSE_FLAGS] );
return STREAM_RESPONSE_MESSAGE_LENGTH;
}
return 0;
}
static int decodeStreamCommand( char *buffer, int length, char& stream_type, unsigned char& update_rate_hz )
{
if ( length < STREAM_CMD_MESSAGE_LENGTH ) return 0;
if ( ( buffer[0] == '!' ) && ( buffer[1] == MSGID_STREAM_CMD ) )
{
if ( !verifyChecksum( buffer, STREAM_CMD_CHECKSUM_INDEX ) ) return 0;
stream_type = buffer[STREAM_CMD_STREAM_TYPE_INDEX];
update_rate_hz = decodeUint8( &buffer[STREAM_CMD_UPDATE_RATE_HZ_INDEX] );
return STREAM_CMD_MESSAGE_LENGTH;
}
return 0;
}
static int decodeYPRUpdate( char *buffer, int length, struct YPRUpdate& update )
{
if ( length < YPR_UPDATE_MESSAGE_LENGTH ) return 0;
if ( ( buffer[0] == '!' ) && ( buffer[1] == 'y' ) )
{
if ( !verifyChecksum( buffer, YPR_UPDATE_CHECKSUM_INDEX ) ) return 0;
update.yaw = decodeProtocolFloat( &buffer[YPR_UPDATE_YAW_VALUE_INDEX] );
update.pitch = decodeProtocolFloat( &buffer[YPR_UPDATE_PITCH_VALUE_INDEX] );
update.roll = decodeProtocolFloat( &buffer[YPR_UPDATE_ROLL_VALUE_INDEX] );
update.compass_heading = decodeProtocolFloat( &buffer[YPR_UPDATE_COMPASS_VALUE_INDEX] );
return YPR_UPDATE_MESSAGE_LENGTH;
}
return 0;
}
static int decodeQuaternionUpdate( char *buffer, int length, struct QuaternionUpdate& update )
{
if ( length < QUATERNION_UPDATE_MESSAGE_LENGTH ) return 0;
if ( ( buffer[0] == PACKET_START_CHAR ) && ( buffer[1] == MSGID_QUATERNION_UPDATE ) )
{
if ( !verifyChecksum( buffer, QUATERNION_UPDATE_CHECKSUM_INDEX ) ) return 0;
update.q1 = (int16_t)decodeProtocolUint16( &buffer[QUATERNION_UPDATE_QUAT1_VALUE_INDEX] );
update.q2 = (int16_t)decodeProtocolUint16( &buffer[QUATERNION_UPDATE_QUAT2_VALUE_INDEX] );
update.q3 = (int16_t)decodeProtocolUint16( &buffer[QUATERNION_UPDATE_QUAT3_VALUE_INDEX] );
update.q4 = (int16_t)decodeProtocolUint16( &buffer[QUATERNION_UPDATE_QUAT4_VALUE_INDEX] );
update.accel_x = (int16_t)decodeProtocolUint16( &buffer[QUATERNION_UPDATE_ACCEL_X_VALUE_INDEX] );
update.accel_y = (int16_t)decodeProtocolUint16( &buffer[QUATERNION_UPDATE_ACCEL_Y_VALUE_INDEX] );
update.accel_z = (int16_t)decodeProtocolUint16( &buffer[QUATERNION_UPDATE_ACCEL_Z_VALUE_INDEX] );
update.mag_x = (int16_t)decodeProtocolUint16( &buffer[QUATERNION_UPDATE_MAG_X_VALUE_INDEX] );
update.mag_y = (int16_t)decodeProtocolUint16( &buffer[QUATERNION_UPDATE_MAG_Y_VALUE_INDEX] );
update.mag_z = (int16_t)decodeProtocolUint16( &buffer[QUATERNION_UPDATE_MAG_Z_VALUE_INDEX] );
update.temp_c = decodeProtocolFloat( &buffer[QUATERNION_UPDATE_TEMP_VALUE_INDEX] );
return QUATERNION_UPDATE_MESSAGE_LENGTH;
}
return 0;
}
static int decodeGyroUpdate( char *buffer, int length, struct GyroUpdate& update )
{
if ( length < GYRO_UPDATE_MESSAGE_LENGTH ) return 0;
if ( ( buffer[0] == PACKET_START_CHAR ) && ( buffer[1] == MSGID_GYRO_UPDATE ) )
{
if ( !verifyChecksum( buffer, GYRO_UPDATE_CHECKSUM_INDEX ) ) return 0;
update.gyro_x = decodeProtocolUint16( &buffer[GYRO_UPDATE_GYRO_X_VALUE_INDEX] );
update.gyro_y = decodeProtocolUint16( &buffer[GYRO_UPDATE_GYRO_Y_VALUE_INDEX] );
update.gyro_z = decodeProtocolUint16( &buffer[GYRO_UPDATE_GYRO_Z_VALUE_INDEX] );
update.accel_x = decodeProtocolUint16( &buffer[GYRO_UPDATE_ACCEL_X_VALUE_INDEX] );
update.accel_y = decodeProtocolUint16( &buffer[GYRO_UPDATE_ACCEL_Y_VALUE_INDEX] );
update.accel_z = decodeProtocolUint16( &buffer[GYRO_UPDATE_ACCEL_Z_VALUE_INDEX] );
update.mag_x = (int16_t)decodeProtocolUint16( &buffer[GYRO_UPDATE_MAG_X_VALUE_INDEX] );
update.mag_y = (int16_t)decodeProtocolUint16( &buffer[GYRO_UPDATE_MAG_Y_VALUE_INDEX] );
update.mag_z = (int16_t)decodeProtocolUint16( &buffer[GYRO_UPDATE_MAG_Z_VALUE_INDEX] );
update.temp_c = decodeProtocolUnsignedHundredthsFloat( &buffer[GYRO_UPDATE_TEMP_VALUE_INDEX] );
return GYRO_UPDATE_MESSAGE_LENGTH;
}
return 0;
}
protected:
static void encodeTermination( char *buffer, int total_length, int content_length )
{
if ( ( total_length >= (CHECKSUM_LENGTH + TERMINATOR_LENGTH) ) && ( total_length >= content_length + (CHECKSUM_LENGTH + TERMINATOR_LENGTH) ) )
{
// Checksum
unsigned char checksum = 0;
for ( int i = 0; i < content_length; i++ )
{
checksum += buffer[i];
}
// convert checksum to two ascii bytes
sprintf(&buffer[content_length], "%02X", checksum);
// Message Terminator
sprintf(&buffer[content_length + CHECKSUM_LENGTH], "%s","\r\n");
}
}
// Formats a float as follows
//
// e.g., -129.235
//
// "-129.24"
//
// e.g., 23.4
//
// "+023.40"
static void encodeProtocolFloat( float f, char* buff )
{
char work_buffer[PROTOCOL_FLOAT_LENGTH + 1];
int i;
int temp1 = abs((int)((f - (int)f) * 100));
if ( f < 0 ) buff[0] = '-'; else buff[0] = ' ';
sprintf(work_buffer,"%03d.%02d", abs((int)f), temp1);
for ( i = 0; i < (PROTOCOL_FLOAT_LENGTH-1); i++ ) {
buff[1 + i] = work_buffer[i];
}
}
static void encodeProtocolUint16( uint16_t value, char* buff )
{
sprintf(&buff[0],"%04X", value );
}
static uint16_t decodeProtocolUint16( char *uint16_string )
{
uint16_t decoded_uint16 = 0;
unsigned int shift_left = 12;
for ( int i = 0; i < 4; i++ )
{
unsigned char digit = uint16_string[i] <= '9' ? uint16_string[i] - '0' : ((uint16_string[i] - 'A') + 10);
decoded_uint16 += (((uint16_t)digit) << shift_left);
shift_left -= 4;
}
return decoded_uint16;
}
/* 0 to 655.35 */
static inline float decodeProtocolUnsignedHundredthsFloat( char *uint8_unsigned_hundredths_float ) {
float unsigned_float = (float)decodeProtocolUint16(uint8_unsigned_hundredths_float);
unsigned_float /= 100;
return unsigned_float;
}
static inline void encodeProtocolUnsignedHundredthsFloat( float input, char *uint8_unsigned_hundredths_float) {
uint16_t input_as_uint = (uint16_t)(input * 100.0f);
encodeProtocolUint16(input_as_uint,uint8_unsigned_hundredths_float);
}
static bool verifyChecksum( char *buffer, int content_length )
{
// Calculate Checksum
unsigned char checksum = 0;
for ( int i = 0; i < content_length; i++ )
{
checksum += buffer[i];
}
// Decode Checksum
unsigned char decoded_checksum = decodeUint8( &buffer[content_length] );
return ( checksum == decoded_checksum );
}
static unsigned char decodeUint8( char *checksum )
{
unsigned char first_digit = checksum[0] <= '9' ? checksum[0] - '0' : ((checksum[0] - 'A') + 10);
unsigned char second_digit = checksum[1] <= '9' ? checksum[1] - '0' : ((checksum[1] - 'A') + 10);
unsigned char decoded_checksum = (first_digit * 16) + second_digit;
return decoded_checksum;
}
static float decodeProtocolFloat( char *buffer )
{
char temp[PROTOCOL_FLOAT_LENGTH+1];
for ( int i = 0; i < PROTOCOL_FLOAT_LENGTH; i++ )
{
temp[i] = buffer[i];
}
temp[PROTOCOL_FLOAT_LENGTH] = 0;
return atof(temp);
}
};
#endif // _IMU_PROTOCOL_H_