encoder.c

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/**************************************************************************/
#include "encoder.h"
#include "spi.h"
#include "gd32f1x0.h"
#include "foc.h"
#include "timer.h"
#include "system.h"
#include "config.h"
#include "filter.h"
 
volatile unsigned short machine_angle_offset = 0;
volatile static unsigned short last_mechanical_angle = 0;
volatile static long long total_machine_angle = 0;
volatile static long long systick_mechanical_angle_last = 0;
 
void encoder_delay(void) {
    /* use loop functions to delay time */
    unsigned char delay_counter = 0xff;
    while (delay_counter)
        delay_counter--;
}
 
unsigned short encoder_read_data(unsigned short TxData) {
    unsigned short data;
 
    /* pull down the CS pin and prepare to send data */
    gpio_bit_write(GPIOA, GPIO_PIN_4, RESET);
    encoder_delay();
 
    /* call SPI related functions to send and receive data */
    data = spi_readwrite_halfworld(TxData);
    encoder_delay();
 
    /* pull up CS pin to end sending data */
    gpio_bit_write(GPIOA, GPIO_PIN_4, SET);
    return data;
}
 
unsigned short encoder_get_mechanical_angle(void) {
    /* read back register raw data */
    unsigned short angle = encoder_read_data(0x0000) >> 4;
 
    /* statistical total rotation angle */
    total_machine_angle = total_machine_angle + angle - last_mechanical_angle;
    last_mechanical_angle = angle;
 
    /* returns the result of subtracting the offset. */
    return ((total_machine_angle - machine_angle_offset) % ENCODER_RESO);
}
 
float encoder_get_electronic_angle(void) {
    /* read back the mechanical angle directly from the magnetic encoder */
    unsigned short tmp_mechanical_angle = encoder_get_mechanical_angle();
 
    /* calculate and update the mechanical angle and electric angle */
    FOC_Struct.mechanical_angle = (float) tmp_mechanical_angle * MECHANGLE_COEFFICIENT;
    float electric_angle = (float) (tmp_mechanical_angle % (ENCODER_RESO / POLAR_PAIRS)) * ELECANGLE_COEFFICIENT;
    return electric_angle;
}
 
void encoder_update_speed(void) {
    /* calculate the difference between this angle and the last angle */
    short tmp_mechanical_angle_velocity = (short) (total_machine_angle - systick_mechanical_angle_last);
 
    /* send it to low-pass filter for filtering to prevent PID high-frequency oscillation */
    FOC_Struct.rotate_speed =
        filter_update_value((Filter_Structure_t *) &velocity_filter, tmp_mechanical_angle_velocity);
    systick_mechanical_angle_last = total_machine_angle;
}
 
void encoder_zeroing(void) {
    float u, v, w;
    /* delay to wait for the power supply voltage to be normal */
    delayms(1000);
 
    /* set that there is only a magnetic field on the straight axis. */
    foc_calculate_dutycycle(0, CALI_TORQUE, 0, &u, &v, &w);
    update_pwm_dutycycle(u, v, w);
    delayms(300);
    machine_angle_offset = 0;
    total_machine_angle = 0;
 
    /* read the angle at this time as the offset angle */
    machine_angle_offset = encoder_read_data(0x0000) >> 4;
 
    /* zero the torque in all directions to release the motor */
    foc_calculate_dutycycle(0, 0, 0, &u, &v, &w);
    update_pwm_dutycycle(u, v, w);
    delayms(300);
}