用pwm控制无源蜂鸣器出现的问题 - Discuz! Board

主函数
#include <stdbool.h>
#include <stdint.h>
#include "nrf.h"
#include "nrf_gpio.h"
#include "nrf_delay.h"
#include "nrf_pwm.h"
#include "boards.h"
#define FREQ_HALF_NOTE_FACTOR 1.059463f
nrf_pwm_config_t pwm_config = PWM_DEFAULT_CONFIG;
void pwm_init(nrf_pwm_mode_t nrf_pwm_mode)
{
pwm_config.mode = nrf_pwm_mode;
// Initialize the PWM library
nrf_pwm_init(&pwm_config);
nrf_delay_ms(300);
}
int main(void)
{
pwm_config.num_channels = 4;
pwm_config.gpio_num[0] = 7;
pwm_config.gpio_num[1] = 6;
pwm_config.gpio_num[2] = 5;
pwm_config.gpio_num[3] = 4;
NRF_TIMER1->MODE =TIMER_MODE_MODE_Timer;
// Start the external 16 MHz clock for a more accurate PWM frequency
NRF_CLOCK->TASKS_HFCLKSTART = 1;
//pwm_init(PWM_MODE_C);
while (true)
{
pwm_init(PWM_MODE_C);
pwm_init(PWM_MODE_D);
pwm_init(PWM_MODE_E);
pwm_init(PWM_MODE_F);
// pwm_init(PWM_MODE_G);
// pwm_init(PWM_MODE_A);
// pwm_init(PWM_MODE_B);
}
}<div class="blockcode"><blockquote>
uint32_t nrf_pwm_init(nrf_pwm_config_t *config)
{
if(config->num_channels == 0 || config->num_channels > PWM_MAX_CHANNELS) return 0xFFFFFFFF;
switch(config->mode)
{
case PWM_MODE_C: // 8-bit resolution, 520Hz PWM frequency, 1us 1923
PWM_TIMER->PRESCALER = 4;
pwm_max_value = 1923;
nrf_pwm_set_value(0, 960);
break;
case PWM_MODE_D: // 8-bit resolution, 585Hz PWM frequency, 1us 1709
PWM_TIMER->PRESCALER = 4;
pwm_max_value = 1709;
nrf_pwm_set_value(1, 850);
break;
case PWM_MODE_E: // 0-1000 resolution, 650Hz PWM frequency, 1us 1538
PWM_TIMER->PRESCALER = 4;
pwm_max_value = 1538;
nrf_pwm_set_value(2, 765);
break;
case PWM_MODE_F: // 0-100 resolution, 693Hz PWM frequency, 1us
PWM_TIMER->PRESCALER = 4;
pwm_max_value = 1443;
nrf_pwm_set_value(3, 720);
break;
case PWM_MODE_G: // 8-bit resolution, 780Hz PWM frequency, 1us
PWM_TIMER->PRESCALER = 4;
pwm_max_value = 1282;
nrf_pwm_set_value(0, 640);
break;
case PWM_MODE_A: // 8-bit resolution, 867Hz PWM frequency, 1us
PWM_TIMER->PRESCALER = 4;
pwm_max_value = 1153;
nrf_pwm_set_value(0, 575);
break;
case PWM_MODE_B: // 8-bit resolution, 975Hz PWM frequency, 1us
PWM_TIMER->PRESCALER = 4;
pwm_max_value = 1026;
nrf_pwm_set_value(0, 510);
break;
default:
return 0xFFFFFFFF;
}
pwm_cc_update_margin_ticks = pwm_cc_margin_by_prescaler[PWM_TIMER->PRESCALER];
pwm_num_channels = config->num_channels;
for(int i = 0; i < pwm_num_channels; i++)
{
pwm_io_ch[i] = (uint32_t)config->gpio_num[i];
nrf_gpio_cfg_output(pwm_io_ch[i]);
pwm_running[i] = 0;
pwm_gpiote_channel[i] = config->gpiote_channel[i];
}
PWM_TIMER->TASKS_CLEAR = 1;
PWM_TIMER->BITMODE = TIMER_BITMODE_BITMODE_16Bit;
PWM_TIMER->CC[2] = pwm_next_max_value = pwm_max_value;
PWM_TIMER->MODE = TIMER_MODE_MODE_Timer;
PWM_TIMER->SHORTS = TIMER_SHORTS_COMPARE2_CLEAR_Msk;
PWM_TIMER->EVENTS_COMPARE[0] = PWM_TIMER->EVENTS_COMPARE[1] = PWM_TIMER->EVENTS_COMPARE[2] = PWM_TIMER->EVENTS_COMPARE[3] = 0;
if(pwm_num_channels > 2)
{
PWM_TIMER2->TASKS_CLEAR = 1;
PWM_TIMER2->BITMODE = TIMER_BITMODE_BITMODE_16Bit;
PWM_TIMER2->CC[2] = pwm_next_max_value = pwm_max_value;
PWM_TIMER2->MODE = TIMER_MODE_MODE_Timer;
PWM_TIMER2->SHORTS = TIMER_SHORTS_COMPARE2_CLEAR_Msk;
PWM_TIMER2->EVENTS_COMPARE[0] = PWM_TIMER2->EVENTS_COMPARE[1] = PWM_TIMER2->EVENTS_COMPARE[2] = PWM_TIMER2->EVENTS_COMPARE[3] = 0;
PWM_TIMER2->PRESCALER = PWM_TIMER->PRESCALER;
}
for(int i = 0; i < pwm_num_channels && i < 2; i++)
{
ppi_enable_channel(config->ppi_channel[i*2], &PWM_TIMER->EVENTS_COMPARE[i], &NRF_GPIOTE->TASKS_OUT[pwm_gpiote_channel[i]]);
ppi_enable_channel(config->ppi_channel[i*2+1],&PWM_TIMER->EVENTS_COMPARE[2], &NRF_GPIOTE->TASKS_OUT[pwm_gpiote_channel[i]]);
pwm_modified[i] = false;
}
for(int i = 2; i < pwm_num_channels; i++)
{
ppi_enable_channel(config->ppi_channel[i*2], &PWM_TIMER2->EVENTS_COMPARE[i-2], &NRF_GPIOTE->TASKS_OUT[pwm_gpiote_channel[i]]);
ppi_enable_channel(config->ppi_channel[i*2+1],&PWM_TIMER2->EVENTS_COMPARE[2], &NRF_GPIOTE->TASKS_OUT[pwm_gpiote_channel[i]]);
pwm_modified[i] = false;
}
#if(USE_WITH_SOFTDEVICE == 1)
sd_radio_session_open(nrf_radio_signal_callback);
#else
NVIC_SetPriority(PWM_IRQn, 0);
NVIC_EnableIRQ(PWM_IRQn);
#endif
apply_pan73_workaround(PWM_TIMER, true);
PWM_TIMER->TASKS_START = 1;
if(pwm_num_channels > 2)
{
apply_pan73_workaround(PWM_TIMER2, true);
PWM_TIMER2->TASKS_START = 1;
}
return 0;
}

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