GD32上升沿采样_定时器捕获外部上升沿信号,DMA读取GPIO口数据的问题

在 GD32 上采集外部上升沿信号，可以使用定时器捕获模式。具体步骤如下：

1. 初始化 GPIO 口为输入模式。
2. 初始化定时器为捕获模式，并设置触发源为外部上升沿。
3. 在定时器触发后，通过 DMA 读取 GPIO 口数据。

下面是示例代码：

#include "gd32f30x.h"

#define BUFFER_SIZE 100

uint16_t g_data_buffer[BUFFER_SIZE];
uint8_t g_dma_transfer_complete = 0;

void gpio_init(void)
{
    /* Enable the GPIOB clock */
    rcu_periph_clock_enable(RCU_GPIOB);

    /* Configure PB13 as input */
    gpio_init(GPIOB, GPIO_MODE_IN_FLOATING, GPIO_OSPEED_50MHZ, GPIO_PIN_13);
}

void timer_init(void)
{
    /* Enable the TIMER1 clock */
    rcu_periph_clock_enable(RCU_TIMER1);

    /* Configure TIMER1 channel 1 as input capture */
    timer_ic_parameter_struct timer_icinitpara;
    timer_icinitpara.icpolarity = TIMER_IC_POLARITY_RISING;
    timer_icinitpara.icselection = TIMER_IC_SELECTION_DIRECTTI;
    timer_icinitpara.icprescaler = TIMER_IC_PSC_DIV1;
    timer_icinitpara.icfilter = 0;
    timer_input_capture_config(TIMER1, TIMER_CH_1, &timer_icinitpara);

    /* Configure TIMER1 as up counter with a period of 0xFFFF and a frequency of 72 MHz */
    timer_parameter_struct timer_initpara;
    timer_initpara.prescaler = 0;
    timer_initpara.alignedmode = TIMER_COUNTER_EDGE;
    timer_initpara.counterdirection = TIMER_COUNTER_UP;
    timer_initpara.period = 0xFFFF;
    timer_initpara.clockdivision = TIMER_CKDIV_DIV1;
    timer_init(TIMER1, &timer_initpara);

    /* Enable TIMER1 */
    timer_enable(TIMER1);
}

void dma_init(void)
{
    /* Enable the DMA clock */
    rcu_periph_clock_enable(RCU_DMA);

    /* Configure DMA channel 1 */
    dma_parameter_struct dma_initpara;
    dma_initpara.direction = DMA_PERIPHERAL_TO_MEMORY;
    dma_initpara.peripheral_addr = (uint32_t)&GPIO_BOP(GPIOB);
    dma_initpara.memory_addr = (uint32_t)g_data_buffer;
    dma_initpara.number = BUFFER_SIZE;
    dma_initpara.peripheral_burst = DMA_BURST_SINGLE;
    dma_initpara.memory_burst = DMA_BURST_SINGLE;
    dma_initpara.peripheral_width = DMA_PERIPHERAL_WIDTH_16BIT;
    dma_initpara.memory_width = DMA_MEMORY_WIDTH_16BIT;
    dma_initpara.priority = DMA_PRIORITY_ULTRA_HIGH;
    dma_initpara.m2m = DMA_M2M_DISABLE;
    dma_init(DMA1, DMA_CH1, &dma_initpara);

    /* Enable DMA channel 1 transfer complete interrupt */
    dma_interrupt_enable(DMA1, DMA_CH1, DMA_INT_FTF);

    /* Enable DMA channel 1 */
    dma_channel_enable(DMA1, DMA_CH1);
}

void dma1_channel1_isr(void)
{
    if (dma_interrupt_flag_get(DMA1, DMA_CH1, DMA_INT_FLAG_FTF)) {
        g_dma_transfer_complete = 1;
        dma_interrupt_flag_clear(DMA1, DMA_CH1, DMA_INT_FLAG_FTF);
    }
}

int main(void)
{
    /* Initialize GPIO, TIMER and DMA */
    gpio_init();
    timer_init();
    dma_init();

    /* Enable DMA channel 1 interrupt */
    eclic_irq_enable(DMA1_Channel1_IRQn, 1, 0);

    while (1) {
        /* Wait for DMA transfer complete */
        while (!g_dma_transfer_complete);

        /* Reset DMA transfer complete flag */
        g_dma_transfer_complete = 0;

        /* Process data */
        for (int i = 0; i < BUFFER_SIZE; i++) {
            if (g_data_buffer[i] & GPIO_PIN_13) {
                /* GPIO pin 13 is high */
            } else {
                /* GPIO pin 13 is low */
            }
        }
    }
}

注意，在使用 DMA 读取 GPIO 口数据时，需要将 GPIO 口的地址作为 DMA 的外设地址。这里使用 `GPIO_BOP(GPIOB)` 获取 GPIOB 的输出寄存器地址。另外，DMA 传输完成后需要清除 DMA 传输完成标志，并在 DMA 中断中设置传输完成标志。在主函数中等待传输完成标志，然后处理数据即可。