NRF52832 PWM

1.在sdk_config.h中加入宏

// <e> PWM_ENABLED - nrf_drv_pwm - PWM peripheral driver - legacy layer
//==========================================================
#ifndef PWM_ENABLED
#define PWM_ENABLED 1
#endif
// <o> PWM_DEFAULT_CONFIG_OUT0_PIN - Out0 pin  <0-31> 

#ifndef PWM_DEFAULT_CONFIG_OUT0_PIN
#define PWM_DEFAULT_CONFIG_OUT0_PIN 31
#endif

// <o> PWM_DEFAULT_CONFIG_OUT1_PIN - Out1 pin  <0-31> 

#ifndef PWM_DEFAULT_CONFIG_OUT1_PIN
#define PWM_DEFAULT_CONFIG_OUT1_PIN 31
#endif

// <o> PWM_DEFAULT_CONFIG_OUT2_PIN - Out2 pin  <0-31> 

#ifndef PWM_DEFAULT_CONFIG_OUT2_PIN
#define PWM_DEFAULT_CONFIG_OUT2_PIN 31
#endif

// <o> PWM_DEFAULT_CONFIG_OUT3_PIN - Out3 pin  <0-31> 

#ifndef PWM_DEFAULT_CONFIG_OUT3_PIN
#define PWM_DEFAULT_CONFIG_OUT3_PIN 31
#endif

// <o> PWM_DEFAULT_CONFIG_BASE_CLOCK  - Base clock
 
// <0=> 16 MHz 
// <1=> 8 MHz 
// <2=> 4 MHz 
// <3=> 2 MHz 
// <4=> 1 MHz 
// <5=> 500 kHz 
// <6=> 250 kHz 
// <7=> 125 kHz 

#ifndef PWM_DEFAULT_CONFIG_BASE_CLOCK
#define PWM_DEFAULT_CONFIG_BASE_CLOCK 4
#endif

// <o> PWM_DEFAULT_CONFIG_COUNT_MODE  - Count mode
 
// <0=> Up 
// <1=> Up and Down 

#ifndef PWM_DEFAULT_CONFIG_COUNT_MODE
#define PWM_DEFAULT_CONFIG_COUNT_MODE 0
#endif

// <o> PWM_DEFAULT_CONFIG_TOP_VALUE - Top value 
#ifndef PWM_DEFAULT_CONFIG_TOP_VALUE
#define PWM_DEFAULT_CONFIG_TOP_VALUE 1000
#endif

// <o> PWM_DEFAULT_CONFIG_LOAD_MODE  - Load mode
 
// <0=> Common 
// <1=> Grouped 
// <2=> Individual 
// <3=> Waveform 

#ifndef PWM_DEFAULT_CONFIG_LOAD_MODE
#define PWM_DEFAULT_CONFIG_LOAD_MODE 0
#endif

// <o> PWM_DEFAULT_CONFIG_STEP_MODE  - Step mode
 
// <0=> Auto 
// <1=> Triggered 

#ifndef PWM_DEFAULT_CONFIG_STEP_MODE
#define PWM_DEFAULT_CONFIG_STEP_MODE 0
#endif

// <o> PWM_DEFAULT_CONFIG_IRQ_PRIORITY  - Interrupt priority
 

// <i> Priorities 0,2 (nRF51) and 0,1,4,5 (nRF52) are reserved for SoftDevice
// <0=> 0 (highest) 
// <1=> 1 
// <2=> 2 
// <3=> 3 
// <4=> 4 
// <5=> 5 
// <6=> 6 
// <7=> 7 

#ifndef PWM_DEFAULT_CONFIG_IRQ_PRIORITY
#define PWM_DEFAULT_CONFIG_IRQ_PRIORITY 6
#endif

// <q> PWM0_ENABLED  - Enable PWM0 instance
 

#ifndef PWM0_ENABLED
#define PWM0_ENABLED 1
#endif

// <q> PWM1_ENABLED  - Enable PWM1 instance
 

#ifndef PWM1_ENABLED
#define PWM1_ENABLED 1
#endif

// <q> PWM2_ENABLED  - Enable PWM2 instance
 

#ifndef PWM2_ENABLED
#define PWM2_ENABLED 1
#endif

// <e> PWM_NRF52_ANOMALY_109_WORKAROUND_ENABLED - Enables nRF52 Anomaly 109 workaround for PWM.

// <i> The workaround uses interrupts to wake up the CPU and ensure
// <i> it is active when PWM is about to start a DMA transfer. For
// <i> initial transfer, done when a playback is started via PPI,
// <i> a specific EGU instance is used to generate the interrupt.
// <i> During the playback, the PWM interrupt triggered on SEQEND
// <i> event of a preceding sequence is used to protect the transfer
// <i> done for the next sequence to be played.
//==========================================================
#ifndef PWM_NRF52_ANOMALY_109_WORKAROUND_ENABLED
#define PWM_NRF52_ANOMALY_109_WORKAROUND_ENABLED 0
#endif
// <o> PWM_NRF52_ANOMALY_109_EGU_INSTANCE  - EGU instance used by the nRF52 Anomaly 109 workaround for PWM.
 
// <0=> EGU0 
// <1=> EGU1 
// <2=> EGU2 
// <3=> EGU3 
// <4=> EGU4 
// <5=> EGU5 

#ifndef PWM_NRF52_ANOMALY_109_EGU_INSTANCE
#define PWM_NRF52_ANOMALY_109_EGU_INSTANCE 5
#endif

2.导入文件nrfx_pwm.c到工程中

3.引入头文件

#include "nrf_drv_pwm.h"

4.定义PWM实例

static nrf_drv_pwm_t m_pwm0 = NRF_DRV_PWM_INSTANCE(0);

5.定义变量

// This is for tracking PWM instances being used, so we can unintialize only
// the relevant ones when switching from one demo to another.
#define USED_PWM(idx) (1UL << idx)
static uint8_t m_used = 0;

6.初时化PWM

static void demo3(void)
{
    printf("Demo 3");

    /*
     * This demo uses only one channel, which is reflected on LED 1.
     * The LED blinks three times (200 ms on, 200 ms off), then it stays off
     * for one second.
     * This scheme is performed three times before the peripheral is stopped.
     */

    nrf_drv_pwm_config_t const config0 =
    {
        .output_pins =
        {
            31 | NRF_DRV_PWM_PIN_INVERTED, // channel 0
            NRF_DRV_PWM_PIN_NOT_USED,             // channel 1
            NRF_DRV_PWM_PIN_NOT_USED,             // channel 2
            NRF_DRV_PWM_PIN_NOT_USED,             // channel 3
        },
        .irq_priority = APP_IRQ_PRIORITY_LOWEST,
        .base_clock   = NRF_PWM_CLK_125kHz,
        .count_mode   = NRF_PWM_MODE_UP,
        .top_value    = 25000,
        .load_mode    = NRF_PWM_LOAD_COMMON,
        .step_mode    = NRF_PWM_STEP_AUTO
    };
    APP_ERROR_CHECK(nrf_drv_pwm_init(&m_pwm0, &config0, NULL));
    m_used |= USED_PWM(0);

    // This array cannot be allocated on stack (hence "static") and it must
    // be in RAM (hence no "const", though its content is not changed).
    static uint16_t /*const*/ seq_values[] =
    {
        0x8000,
             0,
        0x8000,
             0,
        0x8000,
             0
    };
    nrf_pwm_sequence_t const seq =
    {
        .values.p_common = seq_values,
        .length          = NRF_PWM_VALUES_LENGTH(seq_values),
        .repeats         = 0,
        .end_delay       = 4
    };

    (void)nrf_drv_pwm_simple_playback(&m_pwm0, &seq, 16, NRF_DRV_PWM_FLAG_STOP);
}
7.在主函数中的处理

 demo3();