树莓派4与stm32串口通信，stm32接收信息，stm32代码

Sure, here is an example code for STM32 to receive information from Raspberry Pi 4 over UART (serial communication):

#include "stm32f4xx.h"
#include <stdio.h>

#define BUFFER_SIZE 100

char rx_buffer[BUFFER_SIZE];
uint8_t rx_index = 0;
uint8_t rx_data_available = 0;

void USART2_IRQHandler(void) {
    if (USART_GetITStatus(USART2, USART_IT_RXNE) != RESET) {
        rx_buffer[rx_index] = USART_ReceiveData(USART2);
        rx_index++;
        if (rx_index >= BUFFER_SIZE) {
            rx_index = 0; // Reset buffer index if it exceeds the buffer size
        }
        rx_data_available = 1;
    }
}

void USART2_Init(void) {
    GPIO_InitTypeDef GPIO_InitStruct;
    USART_InitTypeDef USART_InitStruct;
    NVIC_InitTypeDef NVIC_InitStruct;

    // Enable clock for USART2 and GPIOA
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);

    // Configure pins for USART2
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_2 | GPIO_Pin_3;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_UP;
    GPIO_Init(GPIOA, &GPIO_InitStruct);

    // Connect USART2 pins to AF7
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource2, GPIO_AF_USART2); // USART2_TX
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource3, GPIO_AF_USART2); // USART2_RX

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

    // Enable USART2 interrupt
    NVIC_InitStruct.NVIC_IRQChannel = USART2_IRQn;
    NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStruct.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStruct);

    // Enable USART2 and receive interrupt
    USART_Cmd(USART2, ENABLE);
    USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);
}

int main(void) {
    // Initialize USART2
    USART2_Init();

    while (1) {
        if (rx_data_available) {
            // Process received data
            printf("Received: %s", rx_buffer);

            // Reset buffer and data available flag
            rx_index = 0;
            rx_data_available = 0;
        }
    }
}

Make sure to configure the Raspberry Pi 4 to transmit data over the UART interface correctly as well.