GD32F450定时器输入捕获上升沿触发DMA

GD32F450的定时器可以配置为输入捕获模式，可以使用DMA进行数据传输。以下是一个示例代码，可以实现当定时器的通道1检测到上升沿时，将定时器的CNT值传输到DMA缓存中。

#include "gd32f4xx.h"

#define TIMER_PRESCALER     1000
#define TIMER_PERIOD        100

#define DMA_CHANNEL         DMA_CH4
#define DMA_STREAM          DMA0_STREAM0
#define DMA_CHANNEL_SOURCE  DMA_CHXCTL_CHSEL(TIMER1_OVF)

#define BUFFER_SIZE         10

uint32_t buffer[BUFFER_SIZE];

void dma_config(void)
{
    dma_parameter_struct dma_init_struct;

    rcu_periph_clock_enable(RCU_DMA0);
    dma_deinit(DMA0, DMA_STREAM);

    dma_init_struct.direction = DMA_PERIPHERAL_TO_MEMORY;
    dma_init_struct.memory_addr = (uint32_t)buffer;
    dma_init_struct.memory_width = DMA_MEMORY_WIDTH_32BIT;
    dma_init_struct.number = BUFFER_SIZE;
    dma_init_struct.periph_addr = (uint32_t)&TIMER1_CNT;
    dma_init_struct.periph_inc = DMA_PERIPH_INCREASE_DISABLE;
    dma_init_struct.periph_width = DMA_PERIPHERAL_WIDTH_32BIT;
    dma_init_struct.priority = DMA_PRIORITY_ULTRA_HIGH;
    dma_init_struct.transfer_direction = DMA_MEM_INC;
    dma_init(DMA0, DMA_STREAM, &dma_init_struct);

    dma_circulation_disable(DMA0, DMA_STREAM);
    dma_channel_subperipheral_select(DMA0, DMA_STREAM, DMA_SUBPERI0);
    dma_memory_to_memory_disable(DMA0, DMA_STREAM);
    dma_memory_increment_enable(DMA0, DMA_STREAM);
    dma_peripheral_increment_disable(DMA0, DMA_STREAM);
    dma_transfer_data_size(DMA0, DMA_STREAM, DMA_TRANSFERSIZE_32BIT);
    dma_transfer_enable(DMA0, DMA_STREAM);
}

void timer_config(void)
{
    timer_oc_parameter_struct timer_ocinitpara;
    timer_parameter_struct timer_initpara;

    rcu_periph_clock_enable(RCU_TIMER1);
    rcu_timer_clock_prescaler_config(TIMER_PRESCALER);

    timer_deinit(TIMER1);
    timer_struct_para_init(&timer_initpara);
    timer_initpara.prescaler = TIMER_PRESCALER - 1;
    timer_initpara.period = TIMER_PERIOD - 1;
    timer_initpara.clock_division = TIMER_CKDIV_DIV1;
    timer_initpara.counter_mode = TIMER_COUNTER_UP;
    timer_initpara.repetition_counter = 0;
    timer_init(TIMER1, &timer_initpara);

    timer_channel_input_capture_parameter_struct timer_inputcapturepara;
    timer_channel_struct_para_init(&timer_inputcapturepara);
    timer_inputcapturepara.icpolarity = TIMER_IC_POLARITY_RISING;
    timer_inputcapturepara.icselection = TIMER_IC_SELECTION_DIRECTTI;
    timer_inputcapturepara.icprescaler = TIMER_IC_PSC_DIV1;
    timer_inputcapturepara.icfilter = 0x0;
    timer_input_capture_config(TIMER1, TIMER_CH_1, &timer_inputcapturepara);

    timer_oc_struct_para_init(&timer_ocinitpara);
    timer_channel_output_config(TIMER1, TIMER_CH_1, &timer_ocinitpara);

    timer_interrupt_enable(TIMER1, TIMER_INT_CH1);
    timer_interrupt_flag_clear(TIMER1, TIMER_INT_CH1);

    nvic_irq_enable(TIMER1_IRQn, 0, 0);
    timer_enable(TIMER1);
}

void TIMER1_IRQHandler(void)
{
    if (timer_interrupt_flag_get(TIMER1, TIMER_INT_CH1) == SET) {
        timer_interrupt_flag_clear(TIMER1, TIMER_INT_CH1);
        dma_transfer_disable(DMA0, DMA_STREAM);
        dma_transfer_number_config(DMA0, DMA_STREAM, BUFFER_SIZE);
        dma_channel_select(DMA0, DMA_STREAM, DMA_CHANNEL_SOURCE);
        dma_transfer_enable(DMA0, DMA_STREAM);
    }
}

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

    while (1);
}

在上述代码中，首先需要配置定时器的输入捕获模式和DMA传输模式。然后，在定时器中断处理程序中，检测到定时器通道1检测到上升沿时，禁用DMA传输，配置DMA传输缓冲区大小，并启动DMA传输。在主函数中，不断循环等待中断触发。