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circuitpython/stmhal/servo.c

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#include <stdio.h>
#include "stm32f4xx_hal.h"
#include "nlr.h"
#include "misc.h"
#include "mpconfig.h"
#include "qstr.h"
#include "obj.h"
#include "runtime.h"
#include "timer.h"
#include "servo.h"
/// \moduleref pyb
/// \class Servo - 3-wire hobby servo driver
///
/// Servo controls standard hobby servos with 3-wires (ground, power, signal).
// this servo driver uses hardware PWM to drive servos on PA0, PA1, PA2, PA3 = X1, X2, X3, X4
// TIM2 and TIM5 have CH1, CH2, CH3, CH4 on PA0-PA3 respectively
// they are both 32-bit counters with 16-bit prescaler
// we use TIM5
#define PYB_SERVO_NUM (4)
typedef struct _pyb_servo_obj_t {
mp_obj_base_t base;
uint8_t servo_id;
uint8_t pulse_min; // units of 10us
uint8_t pulse_max; // units of 10us
uint8_t pulse_centre; // units of 10us
uint8_t pulse_angle_90; // units of 10us; pulse at 90 degrees, minus pulse_centre
uint8_t pulse_speed_100; // units of 10us; pulse at 100% forward speed, minus pulse_centre
uint16_t pulse_cur; // units of 10us
uint16_t pulse_dest; // units of 10us
int16_t pulse_accum;
uint16_t time_left;
} pyb_servo_obj_t;
STATIC pyb_servo_obj_t pyb_servo_obj[PYB_SERVO_NUM];
void servo_init(void) {
timer_tim5_init();
// reset servo objects
for (int i = 0; i < PYB_SERVO_NUM; i++) {
pyb_servo_obj[i].base.type = &pyb_servo_type;
pyb_servo_obj[i].servo_id = i + 1;
pyb_servo_obj[i].pulse_min = 64;
pyb_servo_obj[i].pulse_max = 242;
pyb_servo_obj[i].pulse_centre = 150;
pyb_servo_obj[i].pulse_angle_90 = 97;
pyb_servo_obj[i].pulse_speed_100 = 70;
pyb_servo_obj[i].pulse_cur = 150;
pyb_servo_obj[i].pulse_dest = 0;
pyb_servo_obj[i].time_left = 0;
}
}
void servo_timer_irq_callback(void) {
bool need_it = false;
for (int i = 0; i < PYB_SERVO_NUM; i++) {
pyb_servo_obj_t *s = &pyb_servo_obj[i];
if (s->pulse_cur != s->pulse_dest) {
// clamp pulse to within min/max
if (s->pulse_dest < s->pulse_min) {
s->pulse_dest = s->pulse_min;
} else if (s->pulse_dest > s->pulse_max) {
s->pulse_dest = s->pulse_max;
}
// adjust cur to get closer to dest
if (s->time_left <= 1) {
s->pulse_cur = s->pulse_dest;
s->time_left = 0;
} else {
s->pulse_accum += s->pulse_dest - s->pulse_cur;
s->pulse_cur += s->pulse_accum / s->time_left;
s->pulse_accum %= s->time_left;
s->time_left--;
need_it = true;
}
// set the pulse width
switch (s->servo_id) {
case 1: TIM5->CCR1 = s->pulse_cur; break;
case 2: TIM5->CCR2 = s->pulse_cur; break;
case 3: TIM5->CCR3 = s->pulse_cur; break;
case 4: TIM5->CCR4 = s->pulse_cur; break;
}
}
}
if (need_it) {
__HAL_TIM_ENABLE_IT(&TIM5_Handle, TIM_IT_UPDATE);
} else {
__HAL_TIM_DISABLE_IT(&TIM5_Handle, TIM_IT_UPDATE);
}
}
STATIC void servo_init_channel(pyb_servo_obj_t *s) {
uint32_t pin;
uint32_t channel;
switch (s->servo_id) {
case 1: pin = GPIO_PIN_0; channel = TIM_CHANNEL_1; break;
case 2: pin = GPIO_PIN_1; channel = TIM_CHANNEL_2; break;
case 3: pin = GPIO_PIN_2; channel = TIM_CHANNEL_3; break;
case 4: pin = GPIO_PIN_3; channel = TIM_CHANNEL_4; break;
default: return;
}
// GPIO configuration
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.Pin = pin;
GPIO_InitStructure.Mode = GPIO_MODE_AF_PP;
GPIO_InitStructure.Speed = GPIO_SPEED_FAST;
GPIO_InitStructure.Pull = GPIO_NOPULL;
GPIO_InitStructure.Alternate = GPIO_AF2_TIM5;
HAL_GPIO_Init(GPIOA, &GPIO_InitStructure);
// PWM mode configuration
TIM_OC_InitTypeDef oc_init;
oc_init.OCMode = TIM_OCMODE_PWM1;
oc_init.Pulse = s->pulse_cur; // units of 10us
oc_init.OCPolarity = TIM_OCPOLARITY_HIGH;
oc_init.OCFastMode = TIM_OCFAST_DISABLE;
HAL_TIM_PWM_ConfigChannel(&TIM5_Handle, &oc_init, channel);
// start PWM
HAL_TIM_PWM_Start(&TIM5_Handle, channel);
}
/******************************************************************************/
// Micro Python bindings
STATIC mp_obj_t pyb_servo_set(mp_obj_t port, mp_obj_t value) {
int p = mp_obj_get_int(port);
int v = mp_obj_get_int(value);
if (v < 50) { v = 50; }
if (v > 250) { v = 250; }
switch (p) {
case 1: TIM5->CCR1 = v; break;
case 2: TIM5->CCR2 = v; break;
case 3: TIM5->CCR3 = v; break;
case 4: TIM5->CCR4 = v; break;
}
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_2(pyb_servo_set_obj, pyb_servo_set);
STATIC mp_obj_t pyb_pwm_set(mp_obj_t period, mp_obj_t pulse) {
int pe = mp_obj_get_int(period);
int pu = mp_obj_get_int(pulse);
TIM5->ARR = pe;
TIM5->CCR3 = pu;
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_2(pyb_pwm_set_obj, pyb_pwm_set);
STATIC void pyb_servo_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
pyb_servo_obj_t *self = self_in;
print(env, "<Servo %lu at %luus>", self->servo_id, 10 * self->pulse_cur);
}
/// \classmethod \constructor(id)
/// Create a servo object. `id` is 1-4.
STATIC mp_obj_t pyb_servo_make_new(mp_obj_t type_in, uint n_args, uint n_kw, const mp_obj_t *args) {
// check arguments
mp_arg_check_num(n_args, n_kw, 1, 1, false);
// get servo number
machine_int_t servo_id = mp_obj_get_int(args[0]) - 1;
// check servo number
if (!(0 <= servo_id && servo_id < PYB_SERVO_NUM)) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "Servo %d does not exist", servo_id + 1));
}
// get and init servo object
pyb_servo_obj_t *s = &pyb_servo_obj[servo_id];
s->pulse_dest = s->pulse_cur;
s->time_left = 0;
servo_init_channel(s);
return s;
}
/// \method pulse_width([value])
/// Get or set the pulse width in milliseconds.
STATIC mp_obj_t pyb_servo_pulse_width(uint n_args, const mp_obj_t *args) {
pyb_servo_obj_t *self = args[0];
if (n_args == 1) {
// get pulse width, in us
return mp_obj_new_int(10 * self->pulse_cur);
} else {
// set pulse width, in us
self->pulse_dest = mp_obj_get_int(args[1]) / 10;
self->time_left = 0;
servo_timer_irq_callback();
return mp_const_none;
}
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pyb_servo_pulse_width_obj, 1, 2, pyb_servo_pulse_width);
/// \method calibration([pulse_min, pulse_max, pulse_centre, [pulse_angle_90, pulse_speed_100]])
/// Get or set the calibration of the servo timing.
STATIC mp_obj_t pyb_servo_calibration(uint n_args, const mp_obj_t *args) {
pyb_servo_obj_t *self = args[0];
if (n_args == 1) {
// get calibration values
mp_obj_t tuple[5];
tuple[0] = mp_obj_new_int(10 * self->pulse_min);
tuple[1] = mp_obj_new_int(10 * self->pulse_max);
tuple[2] = mp_obj_new_int(10 * self->pulse_centre);
tuple[3] = mp_obj_new_int(10 * (self->pulse_angle_90 + self->pulse_centre));
tuple[4] = mp_obj_new_int(10 * (self->pulse_speed_100 + self->pulse_centre));
return mp_obj_new_tuple(5, tuple);
} else if (n_args >= 4) {
// set min, max, centre
self->pulse_min = mp_obj_get_int(args[1]) / 10;
self->pulse_max = mp_obj_get_int(args[2]) / 10;
self->pulse_centre = mp_obj_get_int(args[3]) / 10;
if (n_args == 4) {
return mp_const_none;
} else if (n_args == 6) {
self->pulse_angle_90 = mp_obj_get_int(args[4]) / 10 - self->pulse_centre;
self->pulse_speed_100 = mp_obj_get_int(args[5]) / 10 - self->pulse_centre;
return mp_const_none;
}
}
// bad number of arguments
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError, "calibration expecting 1, 4 or 6 arguments, got %d", n_args));
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pyb_servo_calibration_obj, 1, 6, pyb_servo_calibration);
/// \method angle([angle, time=0])
/// Get or set the angle of the servo.
///
/// - `angle` is the angle to move to in degrees.
/// - `time` is the number of milliseconds to take to get to the specified angle.
STATIC mp_obj_t pyb_servo_angle(uint n_args, const mp_obj_t *args) {
pyb_servo_obj_t *self = args[0];
if (n_args == 1) {
// get angle
return mp_obj_new_int((self->pulse_cur - self->pulse_centre) * 90 / self->pulse_angle_90);
} else {
#if MICROPY_ENABLE_FLOAT
self->pulse_dest = self->pulse_centre + self->pulse_angle_90 * mp_obj_get_float(args[1]) / 90.0;
#else
self->pulse_dest = self->pulse_centre + self->pulse_angle_90 * mp_obj_get_int(args[1]) / 90;
#endif
if (n_args == 2) {
// set angle immediately
self->time_left = 0;
} else {
// set angle over a given time (given in milli seconds)
self->time_left = mp_obj_get_int(args[2]) / 20;
self->pulse_accum = 0;
}
servo_timer_irq_callback();
return mp_const_none;
}
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pyb_servo_angle_obj, 1, 3, pyb_servo_angle);
/// \method speed([speed, time=0])
/// Get or set the speed of a continuous rotation servo.
///
/// - `speed` is the speed to move to change to, between -100 and 100.
/// - `time` is the number of milliseconds to take to get to the specified speed.
STATIC mp_obj_t pyb_servo_speed(uint n_args, const mp_obj_t *args) {
pyb_servo_obj_t *self = args[0];
if (n_args == 1) {
// get speed
return mp_obj_new_int((self->pulse_cur - self->pulse_centre) * 100 / self->pulse_speed_100);
} else {
#if MICROPY_ENABLE_FLOAT
self->pulse_dest = self->pulse_centre + self->pulse_speed_100 * mp_obj_get_float(args[1]) / 100.0;
#else
self->pulse_dest = self->pulse_centre + self->pulse_speed_100 * mp_obj_get_int(args[1]) / 100;
#endif
if (n_args == 2) {
// set speed immediately
self->time_left = 0;
} else {
// set speed over a given time (given in milli seconds)
self->time_left = mp_obj_get_int(args[2]) / 20;
self->pulse_accum = 0;
}
servo_timer_irq_callback();
return mp_const_none;
}
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pyb_servo_speed_obj, 1, 3, pyb_servo_speed);
STATIC const mp_map_elem_t pyb_servo_locals_dict_table[] = {
{ MP_OBJ_NEW_QSTR(MP_QSTR_pulse_width), (mp_obj_t)&pyb_servo_pulse_width_obj },
{ MP_OBJ_NEW_QSTR(MP_QSTR_calibration), (mp_obj_t)&pyb_servo_calibration_obj },
{ MP_OBJ_NEW_QSTR(MP_QSTR_angle), (mp_obj_t)&pyb_servo_angle_obj },
{ MP_OBJ_NEW_QSTR(MP_QSTR_speed), (mp_obj_t)&pyb_servo_speed_obj },
};
STATIC MP_DEFINE_CONST_DICT(pyb_servo_locals_dict, pyb_servo_locals_dict_table);
const mp_obj_type_t pyb_servo_type = {
{ &mp_type_type },
.name = MP_QSTR_Servo,
.print = pyb_servo_print,
.make_new = pyb_servo_make_new,
.locals_dict = (mp_obj_t)&pyb_servo_locals_dict,
};
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