nRF52832定时器

1 概述
定时器能够被配置为两种模式：定时模式和计数模式,nrf52832有五个定时器，timer0--timer4 。因为SDK已经使用了timer0，所以如果使用了SDK，就不能再使用timer0，只能使用timer1--timer4。
2 常用的函数

函数功能：初始化定时器
ret_code_t nrf_drv_timer_init   (   
    nrf_drv_timer_t const *const    p_instance,  //Pointer to the driver instance structure.
    nrf_drv_timer_config_t const *  p_config,  //Initial configuration. If NULL, the default configuration is used.
    nrf_timer_event_handler_t   timer_event_handler   //Event handler provided by the user. Must not be NULL.
)

函数功能：Function for converting time in milliseconds to timer ticks.
__STATIC_INLINE uint32_t nrf_drv_timer_ms_to_ticks  (   
    nrf_drv_timer_t const *const    p_instance,
    uint32_t    time_ms 
)

函数功能：Function for setting the timer channel in extended compare mode  
void nrf_drv_timer_extended_compare (   
    nrf_drv_timer_t const *const    p_instance,  //Pointer to the driver instance structure.
    nrf_timer_cc_channel_t  cc_channel,  //Compare channel number.
    uint32_t    cc_value,  //Compare value.
    nrf_timer_short_mask_t  timer_short_mask,  //Shortcut between the compare event on the channel and the timer task (STOP or CLEAR).
    bool    enable_int   //Enable or disable the interrupt for the compare channel.
)

函数功能：开启定时器  
void nrf_drv_timer_enable   (   nrf_drv_timer_t const *const    p_instance  )

注意
在nrf_driver_config.c中修改timer的定义

#define TIMER1_ENABLED 0

#if (TIMER1_ENABLED == 1)
#define TIMER1_CONFIG_FREQUENCY    NRF_TIMER_FREQ_16MHz  //Timer frequency 16 MHz.
#define TIMER1_CONFIG_MODE         TIMER_MODE_MODE_Timer  //选择定时器模式
#define TIMER1_CONFIG_BIT_WIDTH    TIMER_BITMODE_BITMODE_16Bit  //16bit的定时器宽度
#define TIMER1_CONFIG_IRQ_PRIORITY APP_IRQ_PRIORITY_LOW  

#define TIMER1_INSTANCE_INDEX      (TIMER0_ENABLED)
#endif

比如在实验中要开启Timer1，则要把TIMER1_ENABLED宏置为1
3 DEMO

const nrf_drv_timer_t mytimer = NRF_DRV_TIMER_INSTANCE(0);  

void timer_led_handler(nrf_timer_event_t event_type, void* p_context)
{
    switch(event_type)
    {
        case NRF_TIMER_EVENT_COMPARE0:
           //LED翻转
            nrf_gpio_pin_toggle(LED_2);
            break;
        default:break;      
    }
    
    
    
}

int main(void)
{
    uint32_t err_code = NRF_SUCCESS;
    uint32_t time_ms=100;  //100ms 
    uint32_t tick;  
    //配置用于控制LED灯的管脚
    nrf_gpio_cfg_output(LED_2);
    nrf_gpio_pin_set(LED_2);  
 
    //初始化定时器
    err_code=nrf_drv_timer_init(&mytimer,NULL,timer_led_handler);
    //转化时间
    tick=nrf_drv_timer_ms_to_ticks(&mytimer,time_ms);
    //配置
    nrf_drv_timer_extended_compare(&mytimer,NRF_TIMER_CC_CHANNEL0,tick,NRF_TIMER_SHORT_COMPARE0_CLEAR_MASK,true);
    //启动定时器
    nrf_drv_timer_enable(&mytimer);
    
    while (true)
    {

    }     
}

参考资料
1 nRF52832 API
2 艾克姆科技资料

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