【"RV-STAR 开发板免费试用"免费试用】+定时器中断+PWM控制RGB灯分享

ti

`下面弄一下定时器，定时器在一个MCU当中还是很重要的。
GD32VF103VX里面包含了4个定时器，最高工作频率可达108M。
发现RGB的3个LED引脚是连在PA1/PA2/PA3正好在tiMER1的CH1/CH2/CH3
上面。

我们先做普通的定时器中断，让红灯每300ms闪烁一次：

void gd_rvstar_timer1_init(void)
{
      timer_parameter_struct timer_initpara;

      /* ----------------------------------------------------------------------------
      TIMER1 Configuration:
      TIMER1CLK = SystemCoreClock/54000 = 2KHz.//一个节拍 500us
      TIMER1CAR = 600                      //载入值600*500us=300ms
      ---------------------------------------------------------------------------- */
      rcu_periph_clock_enable(RCU_TIMER1);

      timer_deinit(TIMER1);

      timer_update_source_config(TIMER1, TIMER_UPDATE_SRC_REGULAR);

      /* initialize TIMER init parameter struct */
      timer_struct_para_init(&timer_initpara);
      /* TIMER1 configuration */
      timer_initpara.prescaler       = 53999;
      timer_initpara.alignedmode    = TIMER_COUNTER_EDGE;
      timer_initpara.counterdirection  = TIMER_COUNTER_UP;
      timer_initpara.period          = 600;
      timer_initpara.clockdivision    = TIMER_CKDIV_DIV1;
      timer_init(TIMER1, &timer_initpara);

      timer_interrupt_enable(TIMER1, TIMER_INT_UP);
      /* Timer Start */
      timer_enable(TIMER1);
}

void TIMER1_IRQHandler()
{
uint16_t cnt;

if(SET == timer_interrupt_flag_get(TIMER1, TIMER_INT_FLAG_UP)){
      /* clear update interrupt bit */
      timer_interrupt_flag_clear(TIMER1, TIMER_INT_FLAG_UP);

            /* set led to GREEN */
            gd_rvstar_led_off(LED1);
            gd_rvstar_led_off(LED2);
            gd_rvstar_led_toggle(LED3);
}
}

在面函数里面注册该中断：
ECLIC_Register_IRQ(TIMER1_IRQn, ECLIC_NON_VECTOR_INTERRUPT,
                        ECLIC_LEVEL_TRIGGER, 3, 0, NULL);
__enable_irq();
编译下载，现象如下：
时间间隔300ms

接下来，我们通过PWM模式控制RGB灯。此时原来定义的普通引脚就不能用了，复用到PWM通道上了。
关闭了定时器的中断，当然，打开也没问题。
修改定时器初始化代码：
void gd_rvstar_timer1_pwm_init(void)
{
      timer_parameter_struct timer_initpara;
      timer_oc_parameter_struct timer_ocinitpara;

      //PWM引脚定义
      rcu_periph_clock_enable(RCU_GPIOA);
      rcu_periph_clock_enable(RCU_AF);
      /*Configure PA1 PA2 PA3(TIMER1 CH1 CH2 CH3) as alternate function*/
      gpio_init(GPIOA, GPIO_MODE_AF_PP, GPIO_OSPEED_50MHZ, LEDG_PIN);
      gpio_init(GPIOA, GPIO_MODE_AF_PP, GPIO_OSPEED_50MHZ, LEDR_PIN);
      gpio_init(GPIOA, GPIO_MODE_AF_PP, GPIO_OSPEED_50MHZ, LEDB_PIN);

      /* ----------------------------------------------------------------------------
      TIMER2 Configuration:
      TIMER1CLK = SystemCoreClock/108 = 1MHz.//一个节拍1us
      TIMER1CAR = 1000                      //载入值1000*1us=1ms
      ---------------------------------------------------------------------------- */
      rcu_periph_clock_enable(RCU_TIMER1);

      timer_deinit(TIMER1);

      timer_update_source_config(TIMER1, TIMER_UPDATE_SRC_REGULAR);

      /* initialize TIMER init parameter struct */
      timer_struct_para_init(&timer_initpara);
      /* TIMER1 configuration */
      timer_initpara.prescaler       = 108-1;
      timer_initpara.alignedmode    = TIMER_COUNTER_EDGE;
      timer_initpara.counterdirection  = TIMER_COUNTER_UP;
      timer_initpara.period          = 255-1;
      timer_initpara.clockdivision    = TIMER_CKDIV_DIV1;
      timer_initpara.repetitioncounter = 0;
      timer_init(TIMER1, &timer_initpara);

      //timer_interrupt_enable(TIMER1, TIMER_INT_UP);

      /* initialize TIMER channel output parameter struct */
      timer_channel_output_struct_para_init(&timer_ocinitpara);
      /* CH0, CH1 and CH2 configuration in PWM mode */
      timer_ocinitpara.outputstate  = TIMER_CCX_ENABLE;
      timer_ocinitpara.outputnstate = TIMER_CCXN_DISABLE;
      timer_ocinitpara.ocpolarity = TIMER_OC_POLARITY_HIGH;
      timer_ocinitpara.ocnpolarity  = TIMER_OCN_POLARITY_HIGH;
      timer_ocinitpara.ocidlestate  = TIMER_OC_IDLE_STATE_LOW;
      timer_ocinitpara.ocnidlestate = TIMER_OCN_IDLE_STATE_LOW;

      timer_channel_output_config(TIMER1,TIMER_CH_1,&timer_ocinitpara);
      timer_channel_output_config(TIMER1,TIMER_CH_2,&timer_ocinitpara);
      timer_channel_output_config(TIMER1,TIMER_CH_3,&timer_ocinitpara);

      /* CH1 configuration in PWM mode0 */
      timer_channel_output_pulse_value_config(TIMER1,TIMER_CH_1,255);
      timer_channel_output_mode_config(TIMER1,TIMER_CH_1,TIMER_OC_MODE_PWM0);
      timer_channel_output_shadow_config(TIMER1,TIMER_CH_1,TIMER_OC_SHADOW_DISABLE);

      /* CH2 configuration in PWM mode0 */
      timer_channel_output_pulse_value_config(TIMER1,TIMER_CH_2,255);
      timer_channel_output_mode_config(TIMER1,TIMER_CH_2,TIMER_OC_MODE_PWM0);
      timer_channel_output_shadow_config(TIMER1,TIMER_CH_2,TIMER_OC_SHADOW_DISABLE);

      /* CH3 configuration in PWM mode0 */
      timer_channel_output_pulse_value_config(TIMER1,TIMER_CH_3,255);
      timer_channel_output_mode_config(TIMER1,TIMER_CH_3,TIMER_OC_MODE_PWM0);
      timer_channel_output_shadow_config(TIMER1,TIMER_CH_3,TIMER_OC_SHADOW_DISABLE);

      /* auto-reload preload enable */
      timer_auto_reload_shadow_enable(TIMER1);

      /* Timer Start */
      timer_enable(TIMER1);
}

void gd_rvstar_rgb_init(int temp1,int temp2,int temp3)
{
      /* CH1 duty cycle set */
      timer_channel_output_pulse_value_config(TIMER1,TIMER_CH_1,(255-temp2));

      /* CH2 duty cycle set */
      timer_channel_output_pulse_value_config(TIMER1,TIMER_CH_2,(255-temp1));

      /* CH3 duty cycle set */
      timer_channel_output_pulse_value_config(TIMER1,TIMER_CH_3,(255-temp3));
}

在main函数里面添加PWM初始化：
gd_rvstar_timer1_pwm_init();
while里面添加：
for(cnt = 255; cnt >=0; cnt--)
{
gd_rvstar_rgb_init(cnt, 0, 0);
delay_1ms(5);
}
for(cnt = 255; cnt >=0; cnt--)
{
gd_rvstar_rgb_init(0, cnt, 0);
delay_1ms(5);
}
for(cnt = 255; cnt >=0; cnt--)
{
gd_rvstar_rgb_init(0, 0, cnt);
delay_1ms(5);
}

编译下载，现象如下：

`