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circuitpython/ports/stm32/servo.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2013, 2014 Damien P. George
*
* 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.
*/
#include <stdio.h>
#include "py/runtime.h"
#include "py/mphal.h"
#include "pin.h"
#include "timer.h"
#include "servo.h"
#if MICROPY_HW_ENABLE_SERVO
// This file implements the pyb.Servo class which controls standard hobby servo
// motors that have 3-wires (ground, power, signal).
//
// The driver uses hardware PWM to drive servos on pins X1, X2, X3, X4 which are
// assumed to be on PA0, PA1, PA2, PA3 but not necessarily in that order (the
// pins PA0-PA3 are used directly if the X pins are not defined).
//
// TIM2 and TIM5 have CH1-CH4 on PA0-PA3 respectively. They are both 32-bit
// counters with 16-bit prescaler. TIM5 is used by this driver.
#define PYB_SERVO_NUM (4)
typedef struct _pyb_servo_obj_t {
mp_obj_base_t base;
const pin_obj_t *pin;
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].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;
}
// assign servo objects to specific pins (must be some permutation of PA0-PA3)
#ifdef pyb_pin_X1
pyb_servo_obj[0].pin = pyb_pin_X1;
pyb_servo_obj[1].pin = pyb_pin_X2;
pyb_servo_obj[2].pin = pyb_pin_X3;
pyb_servo_obj[3].pin = pyb_pin_X4;
#else
pyb_servo_obj[0].pin = pin_A0;
pyb_servo_obj[1].pin = pin_A1;
pyb_servo_obj[2].pin = pin_A2;
pyb_servo_obj[3].pin = pin_A3;
#endif
}
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
*(&TIM5->CCR1 + s->pin->pin) = s->pulse_cur;
}
}
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) {
static const uint8_t channel_table[4] =
{TIM_CHANNEL_1, TIM_CHANNEL_2, TIM_CHANNEL_3, TIM_CHANNEL_4};
uint32_t channel = channel_table[s->pin->pin];
// GPIO configuration
mp_hal_pin_config(s->pin, MP_HAL_PIN_MODE_ALT, MP_HAL_PIN_PULL_NONE, GPIO_AF2_TIM5);
// 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);
}
/******************************************************************************/
// MicroPython 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(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
pyb_servo_obj_t *self = self_in;
mp_printf(print, "<Servo %lu at %luus>", self - &pyb_servo_obj[0] + 1, 10 * self->pulse_cur);
}
/// \classmethod \constructor(id)
/// Create a servo object. `id` is 1-4.
STATIC mp_obj_t pyb_servo_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
// check arguments
mp_arg_check_num(n_args, n_kw, 1, 1, false);
// get servo number
mp_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) doesn't 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(size_t 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.
// TODO should accept 1 arg, a 5-tuple of values to set
STATIC mp_obj_t pyb_servo_calibration(size_t 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(size_t 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_PY_BUILTINS_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(size_t 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_PY_BUILTINS_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_rom_map_elem_t pyb_servo_locals_dict_table[] = {
{ MP_ROM_QSTR(MP_QSTR_pulse_width), MP_ROM_PTR(&pyb_servo_pulse_width_obj) },
{ MP_ROM_QSTR(MP_QSTR_calibration), MP_ROM_PTR(&pyb_servo_calibration_obj) },
{ MP_ROM_QSTR(MP_QSTR_angle), MP_ROM_PTR(&pyb_servo_angle_obj) },
{ MP_ROM_QSTR(MP_QSTR_speed), MP_ROM_PTR(&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_dict_t*)&pyb_servo_locals_dict,
};
#endif // MICROPY_HW_ENABLE_SERVO
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