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标题: 用gd32f330驱动单极性归零码LED出现波形不对的问题 [打印本页]

作者: tjiefk 时间: 2022-5-12 20:06
标题: 用gd32f330驱动单极性归零码LED出现波形不对的问题
本帖最后由 tjiefk 于 2022-5-12 20:08 编辑

最近有一个项目需要用到RGB LED，选了内置IC的LED灯珠，MCU用GD32F330，PWM+DMA方式，用示波器发现波形不太对，高占空比切到低占空比没有问题，但从低占空比切到高占空比时就出现第一个高占空比波形不对
[attach]586198[/attach]
[attach]586199[/attach]
下面是代码：

#include "rgb_led.h"

const uint8_t g_red[3] = {0x00, 0xff, 0x00};
const uint8_t g_green[3] = {0xff, 0x00, 0x00};
const uint8_t g_blue[3] = {0x00, 0x00, 0xff};

uint16_t g_rgb_led_buf[(24*7+24)]=
{
// ZERO,ZERO,ZERO,ZERO,ONE,ONE,ONE,ONE,
// ZERO,ZERO,ZERO,ZERO,ZERO,ZERO,ZERO,ZERO,
// ZERO,ZERO,ZERO,ZERO,ZERO,ZERO,ZERO,ZERO,
ZERO
};

// uint8_t g_rgb_led_buf[48]=
// {
//    ZERO,ZERO,ZERO,ZERO,ZERO,ZERO,ZERO,ZERO,
//    ZERO,ZERO,ZERO,ZERO,ZERO,ZERO,ZERO,ZERO,
//    ZERO,ZERO,ZERO,ZERO,ONE,ONE,ONE,ONE,
//    0,0,0,0,0,0,0,0,
//    0,0,0,0,0,0,0,0,
//    0,0,0,0,0,0,0,0
// };

void rgb_led_gpio_init(void)
{
rcu_periph_clock_enable(RCU_GPIOB);
/*Configure PB5(TIMER2_CH1) as alternate function*/
gpio_mode_set(GPIOB, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO_PIN_4);
gpio_output_options_set(GPIOB, GPIO_OTYPE_PP, GPIO_OSPEED_50MHZ,GPIO_PIN_4);
gpio_af_set(GPIOB, GPIO_AF_1, GPIO_PIN_4);

}

void timer2_init(void)
{
/* TIMER2 configuration: generate PWM signals with different duty cycles:
TIMER2CLK = SystemCoreClock / 1 = 84MHz */
timer_oc_parameter_struct timer_ocintpara;
timer_parameter_struct timer_initpara;

rcu_periph_clock_enable(RCU_TIMER2);
timer_deinit(TIMER2);

/* TIMER0 configuration */
timer_initpara.prescaler       = 1-1;
timer_initpara.alignedmode    = TIMER_COUNTER_EDGE;
timer_initpara.counterdirection  = TIMER_COUNTER_UP;
timer_initpara.period          = 94-1;          //PWM频率893K
timer_initpara.clockdivision    = TIMER_CKDIV_DIV1;
timer_init(TIMER2,&timer_initpara);

   /* CH0 configuration in PWM mode */
timer_ocintpara.outputstate  = TIMER_CCX_ENABLE;
timer_ocintpara.ocpolarity = TIMER_OC_POLARITY_HIGH;
timer_channel_output_config(TIMER2,TIMER_CH_0,&timer_ocintpara);

timer_channel_output_pulse_value_config(TIMER2,TIMER_CH_0,0);    //占空比66%
timer_channel_output_mode_config(TIMER2,TIMER_CH_0,TIMER_OC_MODE_PWM0);
timer_channel_output_shadow_config(TIMER2,TIMER_CH_0,TIMER_OC_SHADOW_DISABLE);

/* auto-reload preload enable */
//timer_auto_reload_shadow_enable(TIMER2);

timer_dma_disable(TIMER2, TIMER_DMA_CH0D);

}

void rgb_dma_init(void)
{
dma_parameter_struct dma_init_struct;

/* enable DMA clock */
rcu_periph_clock_enable(RCU_DMA);

/* initialize DMA channel */
dma_deinit(DMA_CH3);
/* DMA channel3 initialize */
dma_struct_para_init(&dma_init_struct);
dma_init_struct.direction = DMA_MEMORY_TO_PERIPHERAL;
dma_init_struct.memory_addr = (uint32_t)g_rgb_led_buf;
dma_init_struct.memory_inc = DMA_MEMORY_INCREASE_ENABLE;
dma_init_struct.memory_width = DMA_MEMORY_WIDTH_16BIT;
dma_init_struct.number = 0;
dma_init_struct.periph_addr = (uint32_t)TIMER2_CH0CV_ADDR;
dma_init_struct.periph_inc = DMA_PERIPH_INCREASE_DISABLE;
dma_init_struct.periph_width = DMA_PERIPHERAL_WIDTH_16BIT;
dma_init_struct.priority = DMA_PRIORITY_ULTRA_HIGH;
dma_init(DMA_CH3,&dma_init_struct);
/* 使能循环模式 */
//dma_circulation_enable(DMA_CH3);
/* enable DMA channel3 */

}

void rgb_led_init(void)
{
rgb_led_gpio_init();
rgb_dma_init();
timer2_init();
}

void rgb_led_show(const uint8_t color[], uint16_t len)
{
uint8_t i = 0;
uint16_t memaddr = 0;
uint16_t buffersize = 0;

buffersize = (len * 24)+24;    // number of bytes needed is #LEDs * 24 bytes + 42 trailing bytes
// memaddr = 0;                      // reset buffer memory index

while (len)
{
      /*  green data */
      for(i = 0; i < 8; i++)
      {
         g_rgb_led_buf[memaddr] = ((color[0] << i) & 0x80) ? ONE : ZERO;
         memaddr++;
      }

      /*  red data */
      for(i = 0; i < 8; i++)
      {
         g_rgb_led_buf[memaddr] = ((color[1] << i) & 0x80) ? ONE : ZERO;
         memaddr++;
      }

      /*  blue data */
      for(i = 0; i < 8; i++)
      {
         g_rgb_led_buf[memaddr] = ((color[2] << i) & 0x80) ? ONE : ZERO;
         memaddr++;
      }

      len--;
}
timer_counter_value_config(TIMER2, 0);
dma_transfer_number_config(DMA_CH3, buffersize);
timer_dma_enable(TIMER2, TIMER_DMA_CH0D);
dma_channel_enable(DMA_CH3);
timer_enable(TIMER2);
while(!dma_flag_get(DMA_CH3, DMA_FLAG_FTF));
timer_disable(TIMER2);
dma_channel_disable(DMA_CH3);
dma_flag_clear(DMA_CH3, DMA_FLAG_FTF);
}

作者: tjiefk 时间: 2022-5-14 07:38
终于搞定了，但又出现新问题，第一个脉冲丢失，前面加多少0都没用

作者: 1a2b3c 时间: 2022-5-14 07:59
虽然没有去看你的代码。但是可以提醒你一下，因为正好前几天刚用了PiC的pwm，说的是需要的第一次定时器溢出后再开启pwm输出（pic是操作gpio输出模式使能），这样可以避免第一个脉冲宽度不对的问题，因为可能切换或者刚配置后第一个的时间不是满的，希望有用

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