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/**
* @file st24.h
*
* RC protocol definition for Yuneec ST24 transmitter
*
* @author Lorenz Meier <lm@inf.ethz.ch>
*/
#pragma once
#include <stdint.h>
__BEGIN_DECLS
#define ST24_DATA_LEN_MAX 64
#define ST24_STX1 0x55
#define ST24_STX2 0x55
enum ST24_PACKET_TYPE {
ST24_PACKET_TYPE_CHANNELDATA12 = 0,
ST24_PACKET_TYPE_CHANNELDATA24,
ST24_PACKET_TYPE_TRANSMITTERGPSDATA
};
#pragma pack(push, 1)
typedef struct {
uint8_t header1; ///< 0x55 for a valid packet
uint8_t header2; ///< 0x55 for a valid packet
uint8_t length; ///< length includes type, data, and crc = sizeof(type)+sizeof(data[payload_len])+sizeof(crc8)
uint8_t type; ///< from enum ST24_PACKET_TYPE
uint8_t st24_data[ST24_DATA_LEN_MAX];
uint8_t crc8; ///< crc8 checksum, calculated by st24_common_crc8 and including fields length, type and st24_data
} ReceiverFcPacket;
/**
* RC Channel data (12 channels).
*
* This is incoming from the ST24
*/
typedef struct {
uint16_t t; ///< packet counter or clock
uint8_t rssi; ///< signal strength
uint8_t packet_count; ///< Number of UART packets sent since reception of last RF frame (this tells something about age / rate)
uint8_t channel[18]; ///< channel data, 12 channels (12 bit numbers)
} ChannelData12;
/**
* RC Channel data (12 channels).
*
*/
typedef struct {
uint16_t t; ///< packet counter or clock
uint8_t rssi; ///< signal strength
uint8_t packet_count; ///< Number of UART packets sent since reception of last RF frame (this tells something about age / rate)
uint8_t channel[36]; ///< channel data, 24 channels (12 bit numbers)
} ChannelData24;
/**
* Telemetry packet
*
* This is outgoing to the ST24
*
* imuStatus:
* 8 bit total
* bits 0-2 for status
* - value 0 is FAILED
* - value 1 is INITIALIZING
* - value 2 is RUNNING
* - values 3 through 7 are reserved
* bits 3-7 are status for sensors (0 or 1)
* - mpu6050
* - accelerometer
* - primary gyro x
* - primary gyro y
* - primary gyro z
*
* pressCompassStatus
* 8 bit total
* bits 0-3 for compass status
* - value 0 is FAILED
* - value 1 is INITIALIZING
* - value 2 is RUNNING
* - value 3 - 15 are reserved
* bits 4-7 for pressure status
* - value 0 is FAILED
* - value 1 is INITIALIZING
* - value 2 is RUNNING
* - value 3 - 15 are reserved
*
*/
typedef struct {
uint16_t t; ///< packet counter or clock
int32_t lat; ///< lattitude (degrees) +/- 90 deg
int32_t lon; ///< longitude (degrees) +/- 180 deg
int32_t alt; ///< 0.01m resolution, altitude (meters)
int16_t vx, vy, vz; ///< velocity 0.01m res, +/-320.00 North-East- Down
uint8_t nsat; ///<number of satellites
uint8_t voltage; ///< 25.4V voltage = 5 + 255*0.1 = 30.5V, min=5V
uint8_t current; ///< 0.5A resolution
int16_t roll, pitch, yaw; ///< 0.01 degree resolution
uint8_t motorStatus; ///< 1 bit per motor for status 1=good, 0= fail
uint8_t imuStatus; ///< inertial measurement unit status
uint8_t pressCompassStatus; ///< baro / compass status
} TelemetryData;
#pragma pack(pop)
/**
* CRC8 implementation for ST24 protocol
*
* @param prt Pointer to the data to CRC
* @param len number of bytes to accumulate in the checksum
* @return the checksum of these bytes over len
*/
uint8_t st24_common_crc8(uint8_t *ptr, uint8_t len);
/**
* Decoder for ST24 protocol
*
* @param byte current char to read
* @param rssi pointer to a byte where the RSSI value is written back to
* @param rx_count pointer to a byte where the receive count of packets signce last wireless frame is written back to
* @param channels pointer to a datastructure of size max_chan_count where channel values (12 bit) are written back to
* @param max_chan_count maximum channels to decode - if more channels are decoded, the last n are skipped and success (0) is returned
* @return 0 for success (a decoded packet), 1 for no packet yet (accumulating), 2 for unknown packet, 3 for out of sync, 4 for checksum error
*/
__EXPORT int st24_decode(uint8_t byte, uint8_t *rssi, uint8_t *rx_count, uint16_t *channel_count,
uint16_t *channels, uint16_t max_chan_count);
__END_DECLS
