STM32 按键控制数码管

要用 STM32 控制数码管，需要先连接好 STM32 和数码管，并且要对 STM32 的 GPIO 端口进行配置。以下是一个简单的按键控制数码管的代码示例：

#include "stm32f10x.h"

#define LED_GPIO    GPIOC
#define LED_PIN     GPIO_Pin_13

#define BUTTON_GPIO GPIOA
#define BUTTON_PIN  GPIO_Pin_0

#define SEGMENT_GPIO    GPIOB
#define SEGMENT_PIN_0   GPIO_Pin_0
#define SEGMENT_PIN_1   GPIO_Pin_1
#define SEGMENT_PIN_2   GPIO_Pin_5
#define SEGMENT_PIN_3   GPIO_Pin_6
#define SEGMENT_PIN_4   GPIO_Pin_7
#define SEGMENT_PIN_5   GPIO_Pin_8
#define SEGMENT_PIN_6   GPIO_Pin_9
#define SEGMENT_PIN_7   GPIO_Pin_10

void GPIO_Configuration(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;

    /* LED GPIO pin configuration */
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);
    GPIO_InitStructure.GPIO_Pin = LED_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(LED_GPIO, &GPIO_InitStructure);

    /* Button GPIO pin configuration */
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
    GPIO_InitStructure.GPIO_Pin = BUTTON_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
    GPIO_Init(BUTTON_GPIO, &GPIO_InitStructure);

    /* Segment GPIO pin configuration */
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
    GPIO_InitStructure.GPIO_Pin = SEGMENT_PIN_0 | SEGMENT_PIN_1 | SEGMENT_PIN_2 | SEGMENT_PIN_3 |
                                  SEGMENT_PIN_4 | SEGMENT_PIN_5 | SEGMENT_PIN_6 | SEGMENT_PIN_7;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(SEGMENT_GPIO, &GPIO_InitStructure);
}

int main(void)
{
    GPIO_Configuration();

    uint8_t segment_num = 0;

    while (1)
    {
        if (GPIO_ReadInputDataBit(BUTTON_GPIO, BUTTON_PIN) == RESET)
        {
            /* Button is pressed */
            LED_GPIO->BRR = LED_PIN; /* Turn off LED */
            segment_num++; /* Increment segment number */
            if (segment_num > 9)
            {
                segment_num = 0;
            }
        }
        else
        {
            /* Button is not pressed */
            LED_GPIO->BSRR = LED_PIN; /* Turn on LED */
        }

        /* Display segment number on the 7-segment display */
        switch (segment_num)
        {
        case 0:
            SEGMENT_GPIO->ODR = SEGMENT_PIN_0 | SEGMENT_PIN_1 | SEGMENT_PIN_2 | SEGMENT_PIN_3 |
                                SEGMENT_PIN_4 | SEGMENT_PIN_5;
            break;
        case 1:
            SEGMENT_GPIO->ODR = SEGMENT_PIN_1 | SEGMENT_PIN_2;
            break;
        case 2:
            SEGMENT_GPIO->ODR = SEGMENT_PIN_0 | SEGMENT_PIN_1 | SEGMENT_PIN_3 | SEGMENT_PIN_4 |
                                SEGMENT_PIN_6;
            break;
        case 3:
            SEGMENT_GPIO->ODR = SEGMENT_PIN_0 | SEGMENT_PIN_1 | SEGMENT_PIN_2 | SEGMENT_PIN_3 |
                                SEGMENT_PIN_6;
            break;
        case 4:
            SEGMENT_GPIO->ODR = SEGMENT_PIN_1 | SEGMENT_PIN_2 | SEGMENT_PIN_5 | SEGMENT_PIN_6;
            break;
        case 5:
            SEGMENT_GPIO->ODR = SEGMENT_PIN_0 | SEGMENT_PIN_2 | SEGMENT_PIN_3 | SEGMENT_PIN_5 |
                                SEGMENT_PIN_6;
            break;
        case 6:
            SEGMENT_GPIO->ODR = SEGMENT_PIN_0 | SEGMENT_PIN_2 | SEGMENT_PIN_3 | SEGMENT_PIN_4 |
                                SEGMENT_PIN_5 | SEGMENT_PIN_6;
            break;
        case 7:
            SEGMENT_GPIO->ODR = SEGMENT_PIN_0 | SEGMENT_PIN_1 | SEGMENT_PIN_2;
            break;
        case 8:
            SEGMENT_GPIO->ODR = SEGMENT_PIN_0 | SEGMENT_PIN_1 | SEGMENT_PIN_2 | SEGMENT_PIN_3 |
                                SEGMENT_PIN_4 | SEGMENT_PIN_5 | SEGMENT_PIN_6;
            break;
        case 9:
            SEGMENT_GPIO->ODR = SEGMENT_PIN_0 | SEGMENT_PIN_1 | SEGMENT_PIN_2 | SEGMENT_PIN_3 |
                                SEGMENT_PIN_5 | SEGMENT_PIN_6;
            break;
        }
    }
}

这个代码示例使用 PA0 作为按键输入口，PC13 作为 LED 输出口，以及 PB0~PB7 作为数码管显示口。在循环中，如果按键被按下，那么就会将数码管上的数字加 1，同时会将 LED 关闭；如果按键没有被按下，那么就会将 LED 打开。数码管上的数字通过 switch 语句来实现控制。需要注意的是，在调用 GPIO_Init 函数之前，需要先使能对应 GPIO 端口的时钟。