dshot.h

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#ifndef RCBENCH_DSHOT_H
#define RCBENCH_DSHOT_H
 
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
 
#ifdef __cplusplus
extern "C" {
#endif
 
/* ------------------------------------------------------------- the frame */
 
#define DSHOT_FRAME_BITS      16u   
#define DSHOT_VALUE_MAX     2047u   
#define DSHOT_CMD_MAX         47u   
#define DSHOT_THROTTLE_MIN    48u   
#define DSHOT_THROTTLE_MAX  2047u   

#define DSHOT_CMD_REPEATS     10u

typedef enum {
    DSHOT_CMD_MOTOR_STOP        = 0,
    DSHOT_CMD_BEEP1             = 1,
    DSHOT_CMD_BEEP2             = 2,
    DSHOT_CMD_BEEP3             = 3,
    DSHOT_CMD_BEEP4             = 4,
    DSHOT_CMD_BEEP5             = 5,
    DSHOT_CMD_ESC_INFO          = 6,
    DSHOT_CMD_SPIN_DIRECTION_1  = 7,
    DSHOT_CMD_SPIN_DIRECTION_2  = 8,
    DSHOT_CMD_3D_MODE_OFF       = 9,
    DSHOT_CMD_3D_MODE_ON        = 10,
    DSHOT_CMD_SETTINGS_REQUEST  = 11,
    DSHOT_CMD_SAVE_SETTINGS     = 12,
    DSHOT_CMD_EDT_ENABLE        = 13,
    DSHOT_CMD_EDT_DISABLE       = 14,
    DSHOT_CMD_SPIN_NORMAL       = 20,
    DSHOT_CMD_SPIN_REVERSED     = 21,
} dshot_cmd_t;

uint16_t dshot_frame(uint16_t value, bool telemetry, bool inverted);

uint16_t dshot_throttle(uint16_t command, uint16_t span);
 
/* ------------------------------------------------- the burst coming back */

#define DSHOT_TELEM_BITS   21u

#define DSHOT_TELEM_RATE_NUM 5u
#define DSHOT_TELEM_RATE_DEN 4u

#define DSHOT_EDT_MV_PER_COUNT      250u
#define DSHOT_EDT_A_PER_COUNT       1u
#define DSHOT_EDT_DEGC_PER_COUNT    1u

uint32_t dshot_edt_millivolts(uint16_t count);
uint32_t dshot_edt_amps(uint16_t count);
uint32_t dshot_edt_celsius(uint16_t count);

typedef enum {
    DSHOT_TELEM_ERPM = 0,     
    DSHOT_TELEM_TEMPERATURE,  
    DSHOT_TELEM_VOLTAGE,      
    DSHOT_TELEM_CURRENT,      
    DSHOT_TELEM_DEBUG1,       
    DSHOT_TELEM_DEBUG2,       
    DSHOT_TELEM_STRESS,       
    DSHOT_TELEM_STATUS,       
    DSHOT_TELEM_KINDS,
} dshot_telem_kind_t;

typedef struct {
    dshot_telem_kind_t kind;
    uint16_t payload;        
    uint32_t period_us;      
    uint32_t erpm;           
    uint8_t  value;          
} dshot_telem_t;

bool dshot_gcr_decode(uint32_t line, uint16_t *out);

uint32_t dshot_gcr_encode(uint16_t value);

bool dshot_telem_from_value(uint16_t value, bool edt, dshot_telem_t *out);

bool dshot_telem_decode(uint32_t line, bool edt, dshot_telem_t *out);

uint16_t dshot_telem_value(dshot_telem_kind_t kind, uint16_t payload);

uint32_t dshot_rpm(uint32_t erpm, uint8_t pole_pairs);
 
/* ---------------------------------------- asking for extended telemetry */

#define DSHOT_EDT_RETRY_MS  500u

#define DSHOT_EDT_ASKS       10u

typedef struct {
    uint8_t  left;      
    uint8_t  asks;      
    uint32_t due_ms;    
    bool     answered;  
    bool     asked;     
} dshot_edt_t;

void dshot_edt_bind(dshot_edt_t *e, uint32_t now_ms);

void dshot_edt_idle(dshot_edt_t *e, uint32_t now_ms);

bool dshot_edt_frame(dshot_edt_t *e, bool stopped, uint32_t now_ms);

void dshot_edt_heard(dshot_edt_t *e, dshot_telem_kind_t kind);
 
/* --------------------------------------------------- the captured samples */

bool dshot_rx_bits(const uint32_t *samples, size_t words, uint8_t oversample,
                   uint32_t *line);
 
#ifdef __cplusplus
}
#endif
 
#endif /* RCBENCH_DSHOT_H */