如何正确初始化 I2C stm32? [英] How to properly initialize I2C stm32?

问题描述

我想从 ADXL345 加速度计获取数据，但似乎我错误地连接了它.

I want to get data from ADXL345 accelerometer,but seems that I incorrectly connect it.

SCL- PC6(带 10k 电阻)

SCL- PC6(with 10k resistor)

SDA-PC7(带10k电阻)

SDA- PC7(with 10k resistor)

SDO-地

CS - VCC

地 - 地

3.3v - VCC

这是我要初始化的代码:

Here is my code to initalize:

void I2CG_Init(void)
{
    GPIO_InitTypeDef  GPIO_InitStructure;
    I2C_InitTypeDef  I2C_InitStructure;

    RCC_AHBPeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);
    RCC_AHBPeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);
        // I2CG clock enable
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2CG, ENABLE);
    RCC_AHBPeriphClockCmd(RCC_APB1Periph_I2CG, ENABLE);
    // GPIOB clock enable
    // I2CG SCL and SDA configuration
    GPIO_InitStructure.GPIO_Pin = SCL|SDA;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_OD;
    GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;
    GPIO_Init(GPIOC, &GPIO_InitStructure);
    // Enable I2CG reset state
    RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2CG, ENABLE);
       // Release I2CG from reset state
       RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2CG, DISABLE);
    I2C_DeInit(I2C1);
    I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;
    I2C_InitStructure.I2C_DutyCycle = I2C_DutyCycle_16_9;
    I2C_InitStructure.I2C_OwnAddress1 =  1;
    I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;
    I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
    I2C_InitStructure.I2C_ClockSpeed = ClockSpeed;


    I2C_Init(I2CG, &I2C_InitStructure);
    I2C_Cmd(I2CG, ENABLE);
    I2C_AcknowledgeConfig(I2CG, ENABLE);
}

在一个例子中我看到了

GPIO_PinAFConfig(GPIOC,SCLSource,GPIO_AF_I2CG);

GPIO_PinAFConfig(GPIOC,SDASource,GPIO_AF_I2CG);

但我没有这个 API.

But I don't have this API available.

请帮帮我.我尝试了很多解决方案，也尝试通过 SPI 连接，但没有成功:(请在 I2C 方面提供帮助.

Please help me. I tried many solutions and also tried to connect through SPI, but no success :( Please help with I2C.

推荐答案

SCL- PC6(带 10k 电阻)

SCL- PC6(with 10k resistor)

SDA-PC7(带10k电阻)

SDA- PC7(with 10k resistor)

SCL 和 SDA 应该直接连接.你应该像下面这样使用上拉电阻:http://en.wikipedia.org/wiki/File:I2C.svg

SCL and SDA should be connected directly. You should use pull-up resistors like on this scheme: http://en.wikipedia.org/wiki/File:I2C.svg

你的初始化代码看起来没问题，所以可能是硬件接线错误?

Your initialization code looks ok, so maybe hardware wiring is wrong?

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