STM32F103ZE怎么按下按键后，通过485串口发送数据？

首先，需要初始化STM32F103ZE的GPIO和UART模块。然后，编写中断服务函数来检测按键是否按下。如果按键被按下，就可以在中断服务函数中调用UART发送函数，将数据通过485串口发送出去。

下面是一个简单的示例代码，供参考：

#include "stm32f10x.h"

#define USART1_TX_PIN GPIO_Pin_9
#define USART1_RX_PIN GPIO_Pin_10
#define USART1_GPIO GPIOA
#define USART1 GPIOA
#define USART1_IRQn USART1_IRQn

#define RS485_DIR_PIN GPIO_Pin_8
#define RS485_DIR_GPIO GPIOB

void GPIO_Configuration(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;

    // 初始化USART1的GPIO
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

    GPIO_InitStructure.GPIO_Pin = USART1_TX_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(USART1_GPIO, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = USART1_RX_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(USART1_GPIO, &GPIO_InitStructure);

    // 初始化RS485的GPIO
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);

    GPIO_InitStructure.GPIO_Pin = RS485_DIR_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(RS485_DIR_GPIO, &GPIO_InitStructure);
}

void USART_Configuration(void)
{
    USART_InitTypeDef USART_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);

    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_Rx | USART_Mode_Tx;
    USART_Init(USART1, &USART_InitStructure);

    USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);
    NVIC_EnableIRQ(USART1_IRQn);

    USART_Cmd(USART1, ENABLE);
}

void USART1_IRQHandler(void)
{
    if (USART_GetITStatus(USART1, USART_IT_RXNE) != RESET)
    {
        // 处理接收到的数据
        USART_ClearITPendingBit(USART1, USART_IT_RXNE);
    }
}

void RS485_SendData(uint8_t *data, uint16_t length)
{
    // 设置RS485芯片为发送模式
    GPIO_WriteBit(RS485_DIR_GPIO, RS485_DIR_PIN, Bit_SET);

    for (int i = 0; i < length; i++)
    {
        while (USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);
        USART_SendData(USART1, data[i]);
    }

    while (USART_GetFlagStatus(USART1, USART_FLAG_TC) == RESET);

    // 设置RS485芯片为接收模式
    GPIO_WriteBit(RS485_DIR_GPIO, RS485_DIR_PIN, Bit_RESET);
}

int main(void)
{
    GPIO_Configuration();
    USART_Configuration();

    while (1)
    {
        // 检测按键是否按下
        if (GPIO_ReadInputDataBit(GPIOX, GPIO_PinX) == RESET)
        {
            uint8_t data[] = {0x01, 0x02, 0x03};
            RS485_SendData(data, sizeof(data));
        }
    }
}