[GD32L233C-START Review] 3. PWM to achieve breathing light

freeelectron

[GD32L233C-START Review] 3. PWM to achieve breathing light [Copy link]

Related articles:

[GD32L233C-START Review] 1. GD32L233C-START with obvious advantages and disadvantages (unboxing)

[GD32L233C-START Review] 2. Non-blocking way to light up, blink, blink, blink...

1. Hardware connection

2. PWM channel

It can be seen that PC6 corresponds to the CH0 channel of TIME2.

3. Implementation method

By adjusting the duty cycle and increasing it, the LED gradually becomes brighter, creating a breathing light effect visually.

4. Core code

(1) PWM initialization

void PwmInit(void)
{	
    rcu_periph_clock_enable(RCU_GPIOC);
    /* TIMER1 GPIO */
    gpio_mode_set(GPIOC, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO_PIN_6 );
    gpio_output_options_set(GPIOC, GPIO_OTYPE_PP, GPIO_OSPEED_50MHZ, GPIO_PIN_6);

    gpio_af_set(GPIOC, GPIO_AF_1, GPIO_PIN_6);

    //64000000/6400=10k
	//TIMER2CLK = SystemCoreClock/6400 = 0.01MHz, the period is 1s(100/10000).=0.01s=10ms=100hz

    timer_oc_parameter_struct timer_ocinitpara;
    timer_parameter_struct timer_initpara;

    /* enable the peripherals clock */
    rcu_periph_clock_enable(RCU_TIMER2);

    /* deinit a TIMER */
    timer_deinit(TIMER2);
    /* initialize TIMER init parameter struct */
    timer_struct_para_init(&timer_initpara);
    /* TIMER2 configuration */
    timer_initpara.prescaler        = 6399;
    timer_initpara.alignedmode      = TIMER_COUNTER_EDGE;
    timer_initpara.counterdirection = TIMER_COUNTER_UP;
    timer_initpara.period           = 99;
    timer_initpara.clockdivision    = TIMER_CKDIV_DIV1;
    timer_init(TIMER2, &timer_initpara);

    /* initialize TIMER channel output parameter struct */
    timer_channel_output_struct_para_init(&timer_ocinitpara);
    /* configure TIMER channel output function */
    timer_ocinitpara.outputstate    = TIMER_CCX_ENABLE;
    timer_ocinitpara.ocpolarity     = TIMER_OC_POLARITY_HIGH;
    timer_channel_output_config(TIMER2, TIMER_CH_0, &timer_ocinitpara);

    timer_channel_output_pulse_value_config(TIMER2, TIMER_CH_0, 99);
    /* CH0 configuration in OC timing mode */
    timer_channel_output_mode_config(TIMER2, TIMER_CH_0, TIMER_OC_MODE_PWM0);

    /* enable a TIMER */
    timer_enable(TIMER2);
}

(2) Change the duty cycle

void PwmOut(void)
{
	static uint32_t tick=0;
	
	static  uint8_t out=1;
	
	if(SystemGetTick()-tick>200)
	{
		tick=SystemGetTick();

		out=out+10;
		
		if(out>100)
		{
			out=1;
		}
		
		timer_channel_output_pulse_value_config(TIMER2, TIMER_CH_0, out-1);
	}
}

5. Phenomenon

6. Oscilloscope measurement waveform

mameng

Where is SystemGetTick()

freeelectron

mameng posted on 2022-1-22 20:59 Where is SystemGetTick()

You can see [GD32L233C-START Review] 2. Non-blocking way to light up, blink, blink, blink... This post uses a timer interrupt of 1ms to maintain a global tick

mameng

Project file sharing?

freeelectron

mameng posted on 2022-2-23 09:03 Is the project file shareable?

GD32L233_Project_pwm.rar (360.63 KB, downloads: 3)

2022-2-23 09:37 上传

点击文件名下载附件