stm32f103 VEML335 I2C通信

首先，确保你已经将VEML335传感器正确地连接到STM32F103单片机上，并且I2C总线的连接是正确的。接下来，你可以按照以下步骤进行I2C通信：

1. 初始化I2C总线和GPIO引脚，设置STM32F103单片机为主设备。

2. 通过I2C总线向VEML335传感器发送“写”指令，以设置传感器的寄存器地址。

3. 发送读取指令，读取传感器的数据。

4. 处理读取的数据，以获取VEML335传感器的光强度值。

下面是一个简单的代码示例，可以帮助你开始I2C通信：

#include "stm32f10x.h"

#define VEML335_ADDR 0x10 // VEML335 7-bit I2C address

void I2C_Configuration(void)
{
    I2C_InitTypeDef  I2C_InitStructure;
    GPIO_InitTypeDef  GPIO_InitStructure;

    // Enable GPIOB clock
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);

    // Enable I2C1 clock
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);

    // Configure I2C1 pins: SCL and SDA
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_OD;
    GPIO_Init(GPIOB, &GPIO_InitStructure);

    // Configure I2C1
    I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;
    I2C_InitStructure.I2C_DutyCycle = I2C_DutyCycle_2;
    I2C_InitStructure.I2C_OwnAddress1 = 0x00;
    I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;
    I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
    I2C_InitStructure.I2C_ClockSpeed = 100000;
    I2C_Init(I2C1, &I2C_InitStructure);

    // Enable I2C1
    I2C_Cmd(I2C1, ENABLE);
}

void VEML335_WriteReg(uint8_t reg_addr, uint16_t reg_val)
{
    // Send start condition
    I2C_GenerateSTART(I2C1, ENABLE);

    // Wait until start condition is sent
    while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));

    // Send VEML335 address and set master to write mode
    I2C_Send7bitAddress(I2C1, VEML335_ADDR << 1, I2C_Direction_Transmitter);

    // Wait until VEML335 acknowledges its address
    while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));

    // Send register address
    I2C_SendData(I2C1, reg_addr);

    // Wait until register address is sent
    while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));

    // Send register value (LSB first)
    I2C_SendData(I2C1, reg_val & 0xFF);

    // Wait until register value is sent
    while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));

    // Send register value (MSB next)
    I2C_SendData(I2C1, reg_val >> 8);

    // Wait until register value is sent
    while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));

    // Send stop condition
    I2C_GenerateSTOP(I2C1, ENABLE);
}

uint16_t VEML335_ReadReg(uint8_t reg_addr)
{
    uint16_t reg_val = 0;

    // Send start condition
    I2C_GenerateSTART(I2C1, ENABLE);

    // Wait until start condition is sent
    while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));

    // Send VEML335 address and set master to write mode
    I2C_Send7bitAddress(I2C1, VEML335_ADDR << 1, I2C_Direction_Transmitter);

    // Wait until VEML335 acknowledges its address
    while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));

    // Send register address
    I2C_SendData(I2C1, reg_addr);

    // Wait until register address is sent
    while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_TRANSMITTED));

    // Send repeated start condition
    I2C_GenerateSTART(I2C1, ENABLE);

    // Wait until repeated start condition is sent
    while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));

    // Send VEML335 address and set master to read mode
    I2C_Send7bitAddress(I2C1, VEML335_ADDR << 1, I2C_Direction_Receiver);

    // Wait until VEML335 acknowledges its address
    while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED));

    // Enable ACK for all received bytes except the last one
    I2C_AcknowledgeConfig(I2C1, ENABLE);

    // Read register value (LSB first)
    reg_val = I2C_ReceiveData(I2C1);

    // Wait until register value is received
    while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED));

    // Read register value (MSB next)
    reg_val |= I2C_ReceiveData(I2C1) << 8;

    // Wait until register value is received
    while(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_BYTE_RECEIVED));

    // Disable ACK for the last received byte
    I2C_AcknowledgeConfig(I2C1, DISABLE);

    // Send stop condition
    I2C_GenerateSTOP(I2C1, ENABLE);

    return reg_val;
}

int main(void)
{
    // Initialize I2C
    I2C_Configuration();

    // Write to VEML335 configuration register
    VEML335_WriteReg(0x00, 0x0000);

    // Read VEML335 data register
    uint16_t light_data = VEML335_ReadReg(0x04);

    // Process light data
    // ...

    while(1);
}

请注意，上述代码仅供参考，并且需要根据您的具体硬件和软件需求进行修改。