181 lines
3.5 KiB
C
181 lines
3.5 KiB
C
/* Implementation of PWM support for the Espressif SDK.
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*
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* Part of esp-open-rtos
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* Copyright (C) 2015 Guillem Pascual Ginovart (https://github.com/gpascualg)
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* Copyright (C) 2015 Javier Cardona (https://github.com/jcard0na)
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* BSD Licensed as described in the file LICENSE
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*/
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#include "pwm.h"
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#include <espressif/esp_common.h>
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#include <espressif/sdk_private.h>
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#include <FreeRTOS.h>
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#include <esp8266.h>
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typedef struct PWMPinDefinition
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{
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uint8_t pin;
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uint8_t divider;
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} PWMPin;
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typedef enum {
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PERIOD_ON = 0,
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PERIOD_OFF = 1
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} pwm_step_t;
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typedef struct pwmInfoDefinition
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{
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uint8_t running;
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uint16_t freq;
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uint16_t dutyCycle;
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/* private */
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uint32_t _maxLoad;
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uint32_t _onLoad;
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uint32_t _offLoad;
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pwm_step_t _step;
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uint16_t usedPins;
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PWMPin pins[8];
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} PWMInfo;
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static PWMInfo pwmInfo;
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static void frc1_interrupt_handler(void)
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{
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uint8_t i = 0;
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bool out = true;
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uint32_t load = pwmInfo._onLoad;
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pwm_step_t step = PERIOD_ON;
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if (pwmInfo._step == PERIOD_ON)
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{
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out = false;
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load = pwmInfo._offLoad;
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step = PERIOD_OFF;
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}
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for (; i < pwmInfo.usedPins; ++i)
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{
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gpio_write(pwmInfo.pins[i].pin, out);
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}
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timer_set_load(FRC1, load);
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pwmInfo._step = step;
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}
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void pwm_init(uint8_t npins, const uint8_t* pins)
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{
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/* Assert number of pins is correct */
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if (npins > MAX_PWM_PINS)
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{
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printf("Incorrect number of PWM pins (%d)\n", npins);
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return;
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}
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/* Initialize */
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pwmInfo._maxLoad = 0;
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pwmInfo._onLoad = 0;
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pwmInfo._offLoad = 0;
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pwmInfo._step = PERIOD_ON;
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/* Save pins information */
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pwmInfo.usedPins = npins;
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uint8_t i = 0;
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for (; i < npins; ++i)
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{
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pwmInfo.pins[i].pin = pins[i];
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/* configure GPIOs */
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gpio_enable(pins[i], GPIO_OUTPUT);
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}
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/* Stop timers and mask interrupts */
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pwm_stop();
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/* set up ISRs */
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_xt_isr_attach(INUM_TIMER_FRC1, frc1_interrupt_handler);
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/* Flag not running */
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pwmInfo.running = 0;
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}
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void pwm_set_freq(uint16_t freq)
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{
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pwmInfo.freq = freq;
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/* Stop now to avoid load being used */
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if (pwmInfo.running)
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{
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pwm_stop();
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pwmInfo.running = 1;
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}
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timer_set_frequency(FRC1, freq);
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pwmInfo._maxLoad = timer_get_load(FRC1);
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if (pwmInfo.running)
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{
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pwm_start();
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}
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}
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void pwm_set_duty(uint16_t duty)
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{
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bool output;
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pwmInfo.dutyCycle = duty;
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if (duty > 0 && duty < UINT16_MAX) {
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pwm_restart();
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return;
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}
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// 0% and 100% duty cycle are special cases: constant output.
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pwm_stop();
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pwmInfo.running = 1;
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output = (duty == UINT16_MAX);
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for (uint8_t i = 0; i < pwmInfo.usedPins; ++i)
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{
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gpio_write(pwmInfo.pins[i].pin, output);
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}
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}
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void pwm_restart()
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{
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if (pwmInfo.running)
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{
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pwm_stop();
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pwm_start();
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}
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}
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void pwm_start()
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{
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pwmInfo._onLoad = pwmInfo.dutyCycle * pwmInfo._maxLoad / UINT16_MAX;
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pwmInfo._offLoad = pwmInfo._maxLoad - pwmInfo._onLoad;
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pwmInfo._step = PERIOD_ON;
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// Trigger ON
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uint8_t i = 0;
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for (; i < pwmInfo.usedPins; ++i)
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{
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gpio_write(pwmInfo.pins[i].pin, true);
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}
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timer_set_load(FRC1, pwmInfo._onLoad);
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timer_set_reload(FRC1, false);
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timer_set_interrupts(FRC1, true);
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timer_set_run(FRC1, true);
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pwmInfo.running = 1;
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}
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void pwm_stop()
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{
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timer_set_interrupts(FRC1, false);
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timer_set_run(FRC1, false);
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pwmInfo.running = 0;
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}
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