main/mcpwm_servo_control_example_main.c (mcpwm_servo_control sample)

/* * SPDX-FileCopyrightText: 2022-2023 Espressif Systems (Shanghai) CO LTD * * SPDX-License-Identifier: Apache-2.0 */ #include "freertos/FreeRTOS.h" #include "freertos/task.h" #include "esp_log.h" #include "driver/mcpwm_prelude.h" static const char *TAG = "example"; // Please consult the datasheet of your servo before changing the following parameters #define SERVO_MIN_PULSEWIDTH_US 500 // Minimum pulse width in microsecond #define SERVO_MAX_PULSEWIDTH_US 2500 // Maximum pulse width in microsecond #define SERVO_MIN_DEGREE -90 // Minimum angle #define SERVO_MAX_DEGREE 90 // Maximum angle #define SERVO_PULSE_GPIO 0 // GPIO connects to the PWM signal line #define SERVO_TIMEBASE_RESOLUTION_HZ 1000000 // 1MHz, 1us per tick #define SERVO_TIMEBASE_PERIOD 20000 // 20000 ticks, 20ms static inline uint32_t example_angle_to_compare(int angle) { return (angle - SERVO_MIN_DEGREE) * (SERVO_MAX_PULSEWIDTH_US - SERVO_MIN_PULSEWIDTH_US) / (SERVO_MAX_DEGREE - SERVO_MIN_DEGREE) + SERVO_MIN_PULSEWIDTH_US; } void app_main(void) { ESP_LOGI(TAG, "Create timer and operator"); mcpwm_timer_handle_t timer = NULL; mcpwm_timer_config_t timer_config = { .group_id = 0, .clk_src = MCPWM_TIMER_CLK_SRC_DEFAULT, .resolution_hz = SERVO_TIMEBASE_RESOLUTION_HZ, .period_ticks = SERVO_TIMEBASE_PERIOD, .count_mode = MCPWM_TIMER_COUNT_MODE_UP, }; ESP_ERROR_CHECK(mcpwm_new_timer(&timer_config, &timer)); mcpwm_oper_handle_t oper = NULL; mcpwm_operator_config_t operator_config = { .group_id = 0, // operator must be in the same group to the timer }; ESP_ERROR_CHECK(mcpwm_new_operator(&operator_config, &oper)); ESP_LOGI(TAG, "Connect timer and operator"); ESP_ERROR_CHECK(mcpwm_operator_connect_timer(oper, timer)); ESP_LOGI(TAG, "Create comparator and generator from the operator"); mcpwm_cmpr_handle_t comparator = NULL; mcpwm_comparator_config_t comparator_config = { .flags.update_cmp_on_tez = true, }; ESP_ERROR_CHECK(mcpwm_new_comparator(oper, &comparator_config, &comparator)); mcpwm_gen_handle_t generator = NULL; mcpwm_generator_config_t generator_config = { .gen_gpio_num = SERVO_PULSE_GPIO, }; ESP_ERROR_CHECK(mcpwm_new_generator(oper, &generator_config, &generator)); // set the initial compare value, so that the servo will spin to the center position ESP_ERROR_CHECK(mcpwm_comparator_set_compare_value(comparator, example_angle_to_compare(0))); ESP_LOGI(TAG, "Set generator action on timer and compare event"); // go high on counter empty ESP_ERROR_CHECK(mcpwm_generator_set_action_on_timer_event(generator, MCPWM_GEN_TIMER_EVENT_ACTION(MCPWM_TIMER_DIRECTION_UP, MCPWM_TIMER_EVENT_EMPTY, MCPWM_GEN_ACTION_HIGH))); // go low on compare threshold ESP_ERROR_CHECK(mcpwm_generator_set_action_on_compare_event(generator, MCPWM_GEN_COMPARE_EVENT_ACTION(MCPWM_TIMER_DIRECTION_UP, comparator, MCPWM_GEN_ACTION_LOW))); ESP_LOGI(TAG, "Enable and start timer"); ESP_ERROR_CHECK(mcpwm_timer_enable(timer)); ESP_ERROR_CHECK(mcpwm_timer_start_stop(timer, MCPWM_TIMER_START_NO_STOP)); int angle = 0; int step = 2; while (1) { ESP_LOGI(TAG, "Angle of rotation: %d", angle); ESP_ERROR_CHECK(mcpwm_comparator_set_compare_value(comparator, example_angle_to_compare(angle))); //Add delay, since it takes time for servo to rotate, usually 200ms/60degree rotation under 5V power supply vTaskDelay(pdMS_TO_TICKS(500)); if ((angle + step) > 60 || (angle + step) < -60) { step *= -1; } angle += step; } }