GD32 TIMER — TIMER0 DMA 突发

GD32 GD32F30x_Firmware_Library V3.0.3 TIMER TIMER0 DMA 突发 示例教学

TIMER — TIMER0 DMA 突发

固件库: GD32F30x_Firmware_Library V3.0.3
芯片: GD32
源文件: GD32F30x_Firmware_Library_V3.0.3/Examples/TIMER/TIMER0_dma_burst/main.c


功能简介

本示例演示定时器 DMA 触发。定时器事件自动触发 DMA 传输,无需 CPU 干预,适合波形生成等高速场景。

完整代码

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#include "gd32f30x.h"
#include <stdio.h>
#include "gd32f307c_eval.h"
#define TIMER0_DMATB           ((uint32_t)0x40012C4C)

void gpio_config(void);
void timer_config(void);
void dma_config(void);

/*!
    \brief      configure the GPIO ports
    \param[in]  none
    \param[out] none
    \retval     none
*/
void gpio_config(void)
{
    rcu_periph_clock_enable(RCU_GPIOA);
    rcu_periph_clock_enable(RCU_AF);

    /*configure PA8(TIMER0 CH0) as alternate function*/
    gpio_init(GPIOA,GPIO_MODE_AF_PP,GPIO_OSPEED_50MHZ,GPIO_PIN_8);

    /*configure PA9(TIMER0 CH1) as alternate function*/
    gpio_init(GPIOA,GPIO_MODE_AF_PP,GPIO_OSPEED_50MHZ,GPIO_PIN_9);

    /*configure PA10(TIMER0 CH2) as alternate function*/
    gpio_init(GPIOA,GPIO_MODE_AF_PP,GPIO_OSPEED_50MHZ,GPIO_PIN_10);

    /*configure PA11(TIMER0 CH3) as alternate function*/
    gpio_init(GPIOA,GPIO_MODE_AF_PP,GPIO_OSPEED_50MHZ,GPIO_PIN_11);
}

void dma_config(void)
{
    dma_parameter_struct dma_init_struct;

    /* enable DMA clock */
    rcu_periph_clock_enable(RCU_DMA0);

    /* initialize DMA channel4 */
    dma_deinit(DMA0,DMA_CH4);

    /* DMA channel4 initialize */
    dma_init_struct.periph_addr = (uint32_t)TIMER0_DMATB;
    dma_init_struct.periph_inc = DMA_PERIPH_INCREASE_DISABLE;
    dma_init_struct.memory_addr = (uint32_t)buffer;
    dma_init_struct.memory_inc = DMA_MEMORY_INCREASE_ENABLE;
    dma_init_struct.periph_width = DMA_PERIPHERAL_WIDTH_16BIT;
    dma_init_struct.memory_width = DMA_MEMORY_WIDTH_16BIT;
    dma_init_struct.direction = DMA_MEMORY_TO_PERIPHERAL;
    dma_init_struct.number = 8;
    dma_init_struct.priority = DMA_PRIORITY_ULTRA_HIGH;
    dma_init(DMA0,DMA_CH4,&dma_init_struct);

    dma_circulation_enable(DMA0,DMA_CH4);

    /* enable DMA channel4 */
    dma_channel_enable(DMA0,DMA_CH4);
    
}

void timer_config(void)
{
    /* TIMER0 DMA transfer example -------------------------------------------------
    TIMER0CLK = 120MHz, prescaler = 119 
    TIMER0 counter clock = systemcoreclock/120 = 1MHz.

      The objective is to configure TIMER0 channel 0~3(PA8~PA11) to generate PWM signal.
    capture compare register 0~3 are to be updated twice per circle.On the first update 
    DMA request, data1 is transferred to CH0CV, data2 is transferred to CH1CV, data3 is 
    transferred to CH2CV,data4 is transferred to CH3CV and duty cycle(10%,20%,30%,40%). 
    On the second update DMA request, data5 is transferred to CH0CV, data6 is transferred 
    to CH1CV, data7 is transferred to CH2CV,data8 is transferred to CH3CV and duty cycle
    (50%,60%,70%,80%). 
    -----------------------------------------------------------------------------*/
    timer_oc_parameter_struct timer_ocintpara;
    timer_parameter_struct timer_initpara;

    rcu_periph_clock_enable(RCU_TIMER0);

    timer_deinit(TIMER0);

    /* TIMER0 configuration */
    timer_initpara.prescaler         = 119;
    timer_initpara.alignedmode       = TIMER_COUNTER_EDGE;
    timer_initpara.counterdirection  = TIMER_COUNTER_UP;
    timer_initpara.period            = 999;
    timer_initpara.clockdivision     = TIMER_CKDIV_DIV1;
    timer_initpara.repetitioncounter = 0;
    timer_init(TIMER0,&timer_initpara);

    timer_ocintpara.outputstate  = TIMER_CCX_ENABLE;
    timer_ocintpara.outputnstate = TIMER_CCXN_DISABLE;
    timer_ocintpara.ocpolarity   = TIMER_OC_POLARITY_HIGH;
    timer_ocintpara.ocnpolarity  = TIMER_OCN_POLARITY_HIGH;
    timer_ocintpara.ocidlestate  = TIMER_OC_IDLE_STATE_HIGH;
    timer_ocintpara.ocnidlestate = TIMER_OCN_IDLE_STATE_LOW;

    timer_channel_output_config(TIMER0,TIMER_CH_0,&timer_ocintpara);
    timer_channel_output_config(TIMER0,TIMER_CH_1,&timer_ocintpara);
    timer_channel_output_config(TIMER0,TIMER_CH_2,&timer_ocintpara);
    timer_channel_output_config(TIMER0,TIMER_CH_3,&timer_ocintpara);

    /* CH0 configuration in PWM0 mode */
    timer_channel_output_pulse_value_config(TIMER0,TIMER_CH_0,buffer[0]);
    timer_channel_output_mode_config(TIMER0,TIMER_CH_0,TIMER_OC_MODE_PWM0);
    timer_channel_output_shadow_config(TIMER0,TIMER_CH_0,TIMER_OC_SHADOW_DISABLE);

    /* CH1 configuration in PWM0 mode */
    timer_channel_output_pulse_value_config(TIMER0,TIMER_CH_1,buffer[0]);
    timer_channel_output_mode_config(TIMER0,TIMER_CH_1,TIMER_OC_MODE_PWM0);
    timer_channel_output_shadow_config(TIMER0,TIMER_CH_1,TIMER_OC_SHADOW_DISABLE);

    /* CH2 configuration in PWM0 mode */
    timer_channel_output_pulse_value_config(TIMER0,TIMER_CH_2,buffer[0]);
    timer_channel_output_mode_config(TIMER0,TIMER_CH_2,TIMER_OC_MODE_PWM0);
    timer_channel_output_shadow_config(TIMER0,TIMER_CH_2,TIMER_OC_SHADOW_DISABLE);

    /* CH3 configuration in PWM0 mode */
    timer_channel_output_pulse_value_config(TIMER0,TIMER_CH_3,buffer[0]);
    timer_channel_output_mode_config(TIMER0,TIMER_CH_3,TIMER_OC_MODE_PWM0);
    timer_channel_output_shadow_config(TIMER0,TIMER_CH_3,TIMER_OC_SHADOW_DISABLE);

    /* TIMER0 primary output enable */
    timer_primary_output_config(TIMER0,ENABLE);

    /* TIMER0 update DMA request enable */
    timer_dma_transfer_config(TIMER0,TIMER_DMACFG_DMATA_CH0CV,TIMER_DMACFG_DMATC_4TRANSFER);
    timer_dma_enable(TIMER0,TIMER_DMA_UPD);

    /* auto-reload preload enable */
    timer_auto_reload_shadow_enable(TIMER0);

    /* TIMER0 counter enable */
    timer_enable(TIMER0);
}

int main(void)
{
    gpio_config(); 
    dma_config();
    timer_config();

    while (1);
}

代码讲解

GPIO 配置:设置引脚为输出/输入模式,选择推挽/开漏输出,配置上拉/下拉。

DMA 配置:设置源地址、目标地址、传输方向、数据宽度。DMA 搬运数据不占用 CPU。

定时器配置:设置预分频器(PSC)和重装载值(ARR),定时时间 = (PSC+1) × (ARR+1) / 时钟频率。

PWM 配置:在定时器基础上设置比较值(CCR),占空比 = CCR / (ARR+1)。CCR 越大占空比越高。

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