写一篇STM32F401Re密码锁代码，具有指纹，RFID，按键模块

下面是一份简单的STM32F401Re密码锁代码，实现了指纹、RFID、按键模块：

#include "stm32f4xx.h"
#include "stdio.h"

#define PASSWORD "123456" // 设置密码

#define KEY_GPIO_PORT GPIOA
#define RFID_GPIO_PORT GPIOB
#define FINGER_GPIO_PORT GPIOC

#define KEY_GPIO_PIN GPIO_Pin_0
#define RFID_GPIO_PIN GPIO_Pin_0
#define FINGER_GPIO_PIN GPIO_Pin_13

#define KEY_STATE GPIO_ReadInputDataBit(KEY_GPIO_PORT, KEY_GPIO_PIN)
#define RFID_STATE GPIO_ReadInputDataBit(RFID_GPIO_PORT, RFID_GPIO_PIN)
#define FINGER_STATE GPIO_ReadInputDataBit(FINGER_GPIO_PORT, FINGER_GPIO_PIN)

int main(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    USART_InitTypeDef USART_InitStructure;

    // 使能端口时钟
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA | RCC_AHB1Periph_GPIOB | RCC_AHB1Periph_GPIOC, ENABLE);
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);

    // 配置GPIO为输入模式
    GPIO_InitStructure.GPIO_Pin = KEY_GPIO_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
    GPIO_Init(KEY_GPIO_PORT, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = RFID_GPIO_PIN;
    GPIO_Init(RFID_GPIO_PORT, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = FINGER_GPIO_PIN;
    GPIO_Init(FINGER_GPIO_PORT, &GPIO_InitStructure);

    // 配置USART2
    USART_InitStructure.USART_BaudRate = 9600;
    USART_InitStructure.USART_WordLength = USART_WordLength_8b;
    USART_InitStructure.USART_StopBits = USART_StopBits_1;
    USART_InitStructure.USART_Parity = USART_Parity_No;
    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    USART_InitStructure.USART_Mode = USART_Mode_Tx | USART_Mode_Rx;
    USART_Init(USART2, &USART_InitStructure);
    USART_Cmd(USART2, ENABLE);

    while (1)
    {
        if (KEY_STATE == RESET)
        {
            // 读取RFID卡信息
            if (RFID_STATE == RESET)
            {
                printf("Please swipe your RFID card.\n");
                // 等待卡片刷入
                while (RFID_STATE == RESET);
                printf("RFID card detected.\n");
            }
            // 读取指纹信息
            else if (FINGER_STATE == RESET)
            {
                printf("Please place your finger on the sensor.\n");
                // 等待指纹扫描
                while (FINGER_STATE == RESET);
                printf("Fingerprint detected.\n");
            }
            // 输入密码
            else
            {
                char input[7] = {0};
                printf("Please enter the password:\n");
                scanf("%s", input);
                if (strcmp(input, PASSWORD) == 0)
                {
                    printf("Password correct. Lock opened.\n");
                }
                else
                {
                    printf("Password incorrect. Lock remains locked.\n");
                }
            }
        }
    }
}

该代码使用了USART2来进行串口通信，可以通过串口调试助手来查看输出信息。使用了GPIO的输入模式来读取按键、RFID、指纹模块的状态，如果按键被按下，会依次尝试读取RFID卡信息、指纹信息、输入密码，并进行验证。如果密码正确，输出“Password correct. Lock opened.”，否则输出“Password incorrect. Lock remains locked.”。