/* * This file is part of the MicroPython project, http://micropython.org/ * * The MIT License (MIT) * * Copyright (c) 2020-2021 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. */ // This file is never compiled standalone, it's included directly from // extmod/machine_pwm.c via MICROPY_PY_MACHINE_PWM_INCLUDEFILE. #include "py/mphal.h" #include "hardware/clocks.h" #include "hardware/pwm.h" /******************************************************************************/ // MicroPython bindings for machine.PWM typedef struct _machine_pwm_obj_t { mp_obj_base_t base; uint8_t slice; uint8_t channel; uint8_t invert; uint8_t duty_type; mp_int_t duty; } machine_pwm_obj_t; enum { VALUE_NOT_SET = -1, DUTY_NOT_SET = 0, DUTY_U16, DUTY_NS }; static machine_pwm_obj_t machine_pwm_obj[] = { {{&machine_pwm_type}, 0, PWM_CHAN_A, 0, DUTY_NOT_SET, 0 }, {{&machine_pwm_type}, 0, PWM_CHAN_B, 0, DUTY_NOT_SET, 0 }, {{&machine_pwm_type}, 1, PWM_CHAN_A, 0, DUTY_NOT_SET, 0 }, {{&machine_pwm_type}, 1, PWM_CHAN_B, 0, DUTY_NOT_SET, 0 }, {{&machine_pwm_type}, 2, PWM_CHAN_A, 0, DUTY_NOT_SET, 0 }, {{&machine_pwm_type}, 2, PWM_CHAN_B, 0, DUTY_NOT_SET, 0 }, {{&machine_pwm_type}, 3, PWM_CHAN_A, 0, DUTY_NOT_SET, 0 }, {{&machine_pwm_type}, 3, PWM_CHAN_B, 0, DUTY_NOT_SET, 0 }, {{&machine_pwm_type}, 4, PWM_CHAN_A, 0, DUTY_NOT_SET, 0 }, {{&machine_pwm_type}, 4, PWM_CHAN_B, 0, DUTY_NOT_SET, 0 }, {{&machine_pwm_type}, 5, PWM_CHAN_A, 0, DUTY_NOT_SET, 0 }, {{&machine_pwm_type}, 5, PWM_CHAN_B, 0, DUTY_NOT_SET, 0 }, {{&machine_pwm_type}, 6, PWM_CHAN_A, 0, DUTY_NOT_SET, 0 }, {{&machine_pwm_type}, 6, PWM_CHAN_B, 0, DUTY_NOT_SET, 0 }, {{&machine_pwm_type}, 7, PWM_CHAN_A, 0, DUTY_NOT_SET, 0 }, {{&machine_pwm_type}, 7, PWM_CHAN_B, 0, DUTY_NOT_SET, 0 }, }; static bool defer_start; static bool slice_freq_set[8]; static void mp_machine_pwm_freq_set(machine_pwm_obj_t *self, mp_int_t freq); static void mp_machine_pwm_duty_set_u16(machine_pwm_obj_t *self, mp_int_t duty_u16); static void mp_machine_pwm_duty_set_ns(machine_pwm_obj_t *self, mp_int_t duty_ns); static void mp_machine_pwm_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) { machine_pwm_obj_t *self = MP_OBJ_TO_PTR(self_in); mp_printf(print, "", self->slice, self->channel, self->invert); } void machine_pwm_start(machine_pwm_obj_t *self) { // Start the PWM if properly set. if (defer_start == false && slice_freq_set[self->slice] == true && self->duty_type != DUTY_NOT_SET) { if (self->channel == PWM_CHAN_A) { pwm_set_output_polarity(self->slice, self->invert, (self + 1)->invert); } else { pwm_set_output_polarity(self->slice, (self - 1)->invert, self->invert); } pwm_set_enabled(self->slice, true); } } static void mp_machine_pwm_init_helper(machine_pwm_obj_t *self, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) { enum { ARG_freq, ARG_duty_u16, ARG_duty_ns, ARG_invert }; static const mp_arg_t allowed_args[] = { { MP_QSTR_freq, MP_ARG_INT, {.u_int = VALUE_NOT_SET} }, { MP_QSTR_duty_u16, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = VALUE_NOT_SET} }, { MP_QSTR_duty_ns, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = VALUE_NOT_SET} }, { MP_QSTR_invert, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = VALUE_NOT_SET} }, }; // Parse the arguments. mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)]; mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args); // defer starting PWM until all provided args are checked. defer_start = true; if (args[ARG_freq].u_int != VALUE_NOT_SET) { mp_machine_pwm_freq_set(self, args[ARG_freq].u_int); } if (args[ARG_duty_u16].u_int != VALUE_NOT_SET) { mp_machine_pwm_duty_set_u16(self, args[ARG_duty_u16].u_int); } if (args[ARG_duty_ns].u_int != VALUE_NOT_SET) { mp_machine_pwm_duty_set_ns(self, args[ARG_duty_ns].u_int); } if (args[ARG_invert].u_int != VALUE_NOT_SET) { self->invert = !!args[ARG_invert].u_int; } defer_start = false; machine_pwm_start(self); } // PWM(pin [, args]) static mp_obj_t mp_machine_pwm_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) { // Check number of arguments mp_arg_check_num(n_args, n_kw, 1, MP_OBJ_FUN_ARGS_MAX, true); // Get GPIO to connect to PWM. uint32_t gpio = mp_hal_get_pin_obj(all_args[0]); // Get static peripheral object. uint slice = pwm_gpio_to_slice_num(gpio); uint8_t channel = pwm_gpio_to_channel(gpio); machine_pwm_obj_t *self = &machine_pwm_obj[slice * 2 + channel]; self->invert = 0; self->duty_type = DUTY_NOT_SET; // Process the remaining parameters. mp_map_t kw_args; mp_map_init_fixed_table(&kw_args, n_kw, all_args + n_args); mp_machine_pwm_init_helper(self, n_args - 1, all_args + 1, &kw_args); // Select PWM function for given GPIO. gpio_set_function(gpio, GPIO_FUNC_PWM); return MP_OBJ_FROM_PTR(self); } // Stop all active slices. void machine_pwm_deinit_all(void) { for (int i = 0; i < 8; i++) { slice_freq_set[i] = false; pwm_set_enabled(machine_pwm_obj[i].slice, false); } } static void mp_machine_pwm_deinit(machine_pwm_obj_t *self) { pwm_set_enabled(self->slice, false); } // Returns: floor((16*F + offset) / div16) // Avoids overflow in the numerator that would occur if // 16*F + offset > 2**32 // F + offset/16 > 2**28 = 268435456 (approximately, due to flooring) uint32_t get_slice_hz(uint32_t offset, uint32_t div16) { uint32_t source_hz = clock_get_hz(clk_sys); if (source_hz + offset / 16 > 268000000) { return (16 * (uint64_t)source_hz + offset) / div16; } else { return (16 * source_hz + offset) / div16; } } // Returns 16*F / denom, rounded. uint32_t get_slice_hz_round(uint32_t div16) { return get_slice_hz(div16 / 2, div16); } // Returns ceil(16*F / denom). uint32_t get_slice_hz_ceil(uint32_t div16) { return get_slice_hz(div16 - 1, div16); } static mp_obj_t mp_machine_pwm_freq_get(machine_pwm_obj_t *self) { if (slice_freq_set[self->slice] == true) { uint32_t div16 = pwm_hw->slice[self->slice].div; uint32_t top = pwm_hw->slice[self->slice].top; uint32_t pwm_freq = get_slice_hz_round(div16 * (top + 1)); return MP_OBJ_NEW_SMALL_INT(pwm_freq); } else { return MP_OBJ_NEW_SMALL_INT(0); } } static void mp_machine_pwm_freq_set(machine_pwm_obj_t *self, mp_int_t freq) { // Set the frequency, making "top" as large as possible for maximum resolution. // Maximum "top" is set at 65534 to be able to achieve 100% duty with 65535. #define TOP_MAX 65534 uint32_t source_hz = clock_get_hz(clk_sys); uint32_t div16; uint32_t top; if ((source_hz + freq / 2) / freq < TOP_MAX) { // If possible (based on the formula for TOP below), use a DIV of 1. // This also prevents overflow in the DIV calculation. div16 = 16; // Same as get_slice_hz_round() below but canceling the 16s // to avoid overflow for high freq. top = (source_hz + freq / 2) / freq - 1; } else { // Otherwise, choose the smallest possible DIV for maximum // duty cycle resolution. // Constraint: 16*F/(div16*freq) < TOP_MAX // So: div16 = get_slice_hz_ceil(TOP_MAX * freq); // Set TOP as accurately as possible using rounding. top = get_slice_hz_round(div16 * freq) - 1; } if (div16 < 16) { mp_raise_ValueError(MP_ERROR_TEXT("freq too large")); } else if (div16 >= 256 * 16) { mp_raise_ValueError(MP_ERROR_TEXT("freq too small")); } pwm_hw->slice[self->slice].div = div16; pwm_hw->slice[self->slice].top = top; slice_freq_set[self->slice] = true; if (self->duty_type == DUTY_U16) { mp_machine_pwm_duty_set_u16(self, self->duty); } else if (self->duty_type == DUTY_NS) { mp_machine_pwm_duty_set_ns(self, self->duty); } machine_pwm_obj_t *other = self->channel == PWM_CHAN_A ? self + 1 : self - 1; if (other->duty_type == DUTY_U16) { mp_machine_pwm_duty_set_u16(other, other->duty); } else if (other->duty_type == DUTY_NS) { mp_machine_pwm_duty_set_ns(other, other->duty); } } static mp_obj_t mp_machine_pwm_duty_get_u16(machine_pwm_obj_t *self) { if (self->duty_type != DUTY_NOT_SET && slice_freq_set[self->slice] == true) { uint32_t top = pwm_hw->slice[self->slice].top; uint32_t cc = pwm_hw->slice[self->slice].cc; cc = (cc >> (self->channel ? PWM_CH0_CC_B_LSB : PWM_CH0_CC_A_LSB)) & 0xffff; // Use rounding (instead of flooring) here to give as accurate an // estimate as possible. return MP_OBJ_NEW_SMALL_INT((cc * 65535 + (top + 1) / 2) / (top + 1)); } else { return MP_OBJ_NEW_SMALL_INT(0); } } static void mp_machine_pwm_duty_set_u16(machine_pwm_obj_t *self, mp_int_t duty_u16) { uint32_t top = pwm_hw->slice[self->slice].top; // Limit duty_u16 to 65535 // Use rounding here to set it as accurately as possible. if (duty_u16 > 65535) { duty_u16 = 65535; } uint32_t cc = (duty_u16 * (top + 1) + 65535 / 2) / 65535; pwm_set_chan_level(self->slice, self->channel, cc); self->duty = duty_u16; self->duty_type = DUTY_U16; machine_pwm_start(self); } static mp_obj_t mp_machine_pwm_duty_get_ns(machine_pwm_obj_t *self) { if (self->duty_type != DUTY_NOT_SET && slice_freq_set[self->slice] == true) { uint32_t slice_hz = get_slice_hz_round(pwm_hw->slice[self->slice].div); uint32_t cc = pwm_hw->slice[self->slice].cc; cc = (cc >> (self->channel ? PWM_CH0_CC_B_LSB : PWM_CH0_CC_A_LSB)) & 0xffff; return MP_OBJ_NEW_SMALL_INT(((uint64_t)cc * 1000000000ULL + slice_hz / 2) / slice_hz); } else { return MP_OBJ_NEW_SMALL_INT(0); } } static void mp_machine_pwm_duty_set_ns(machine_pwm_obj_t *self, mp_int_t duty_ns) { uint32_t slice_hz = get_slice_hz_round(pwm_hw->slice[self->slice].div); uint32_t cc = ((uint64_t)duty_ns * slice_hz + 500000000ULL) / 1000000000ULL; uint32_t top = pwm_hw->slice[self->slice].top; if (cc > (top + 1)) { cc = top + 1; } pwm_set_chan_level(self->slice, self->channel, cc); self->duty = duty_ns; self->duty_type = DUTY_NS; machine_pwm_start(self); }