stm32f407使用iic2驱动Pca9685的16通道Pwm代码

以下是使用I2C2驱动PCA9685的16通道PWM代码，需要先初始化I2C2和PCA9685：

#include "stm32f4xx.h"

#define PCA9685_ADDR 0x40 // PCA9685的I2C地址

void I2C2_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStruct;
    I2C_InitTypeDef I2C_InitStruct;

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C2, ENABLE);
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);

    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_10 | GPIO_Pin_11;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStruct.GPIO_OType = GPIO_OType_OD;
    GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_UP;
    GPIO_Init(GPIOB, &GPIO_InitStruct);

    GPIO_PinAFConfig(GPIOB, GPIO_PinSource10, GPIO_AF_I2C2);
    GPIO_PinAFConfig(GPIOB, GPIO_PinSource11, GPIO_AF_I2C2);

    I2C_DeInit(I2C2);
    I2C_InitStruct.I2C_Mode = I2C_Mode_I2C;
    I2C_InitStruct.I2C_DutyCycle = I2C_DutyCycle_2;
    I2C_InitStruct.I2C_OwnAddress1 = 0x00;
    I2C_InitStruct.I2C_Ack = I2C_Ack_Enable;
    I2C_InitStruct.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
    I2C_InitStruct.I2C_ClockSpeed = 100000;
    I2C_Init(I2C2, &I2C_InitStruct);

    I2C_Cmd(I2C2, ENABLE);
}

void PCA9685_Init(void)
{
    uint8_t data[2];

    data[0] = 0x00; // MODE1寄存器地址
    data[1] = 0x01; // 设置PCA9685为普通模式
    I2C_GenerateSTART(I2C2, ENABLE);
    while (!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_MODE_SELECT));
    I2C_Send7bitAddress(I2C2, PCA9685_ADDR, I2C_Direction_Transmitter);
    while (!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));
    I2C_SendData(I2C2, data[0]);
    while (!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
    I2C_SendData(I2C2, data[1]);
    while (!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
    I2C_GenerateSTOP(I2C2, ENABLE);

    data[0] = 0xFE; // PRE_SCALE寄存器地址
    data[1] = 0x03; // 设置PWM时钟频率为50Hz
    I2C_GenerateSTART(I2C2, ENABLE);
    while (!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_MODE_SELECT));
    I2C_Send7bitAddress(I2C2, PCA9685_ADDR, I2C_Direction_Transmitter);
    while (!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));
    I2C_SendData(I2C2, data[0]);
    while (!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
    I2C_SendData(I2C2, data[1]);
    while (!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
    I2C_GenerateSTOP(I2C2, ENABLE);

    data[0] = 0x00; // MODE1寄存器地址
    data[1] = 0x81; // 设置PCA9685为自动增量模式
    I2C_GenerateSTART(I2C2, ENABLE);
    while (!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_MODE_SELECT));
    I2C_Send7bitAddress(I2C2, PCA9685_ADDR, I2C_Direction_Transmitter);
    while (!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));
    I2C_SendData(I2C2, data[0]);
    while (!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
    I2C_SendData(I2C2, data[1]);
    while (!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
    I2C_GenerateSTOP(I2C2, ENABLE);
}

void PCA9685_SetPWM(uint8_t channel, uint16_t on, uint16_t off)
{
    uint8_t data[5];

    data[0] = 0x06 + 4 * channel; // LED0_ON_L寄存器地址
    data[1] = on & 0xFF; // LED0_ON_L
    data[2] = on >> 8; // LED0_ON_H
    data[3] = off & 0xFF; // LED0_OFF_L
    data[4] = off >> 8; // LED0_OFF_H

    I2C_GenerateSTART(I2C2, ENABLE);
    while (!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_MODE_SELECT));
    I2C_Send7bitAddress(I2C2, PCA9685_ADDR, I2C_Direction_Transmitter);
    while (!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED));
    I2C_SendData(I2C2, data[0]);
    while (!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
    I2C_SendData(I2C2, data[1]);
    while (!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
    I2C_SendData(I2C2, data[2]);
    while (!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
    I2C_SendData(I2C2, data[3]);
    while (!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
    I2C_SendData(I2C2, data[4]);
    while (!I2C_CheckEvent(I2C2, I2C_EVENT_MASTER_BYTE_TRANSMITTED));
    I2C_GenerateSTOP(I2C2, ENABLE);
}

int main(void)
{
    I2C2_Init();
    PCA9685_Init();

    while (1)
    {
        // 设置PWM输出
        PCA9685_SetPWM(0, 0, 2048); // 50%占空比
        PCA9685_SetPWM(1, 0, 4096); // 100%占空比
    }
}