PCA9685输出330hz的pwm，怎么设置

要设置PCA9685输出330Hz的PWM信号，需要进行以下步骤：

1. 初始化PCA9685芯片，设置时钟频率和PWM输出频率。

2. 计算PWM的周期，即每个PWM信号的高电平和低电平时间。

3. 根据计算出的PWM周期，设置PCA9685的预分频器和PWM寄存器，以生成所需的PWM信号。

以下是示例代码，用于设置PCA9685输出330Hz的PWM信号：

import Adafruit_PCA9685

pwm = Adafruit_PCA9685.PCA9685()
pwm.set_pwm_freq(330)  # 设置PWM输出频率为330Hz

pwm_period = 1 / 330  # 计算PWM周期
pulse_length = pwm_period / 2  # 计算每个PWM信号的高电平和低电平时间

pulse_length *= 4096  # 将时间转换为占空比

# 设置PWM输出
pwm.set_pwm(channel, 0, int(pulse_length))

其中，`channel`为要设置的PWM通道号，取值范围为0~15。`pwm.set_pwm_freq(330)`设置PCA9685输出频率为330Hz。`pwm.set_pwm(channel, 0, int(pulse_length))`设置PWM输出，其中第一个参数为通道号，第二个参数为PWM输出的起始位置，第三个参数为PWM输出的占空比，需要将计算出的占空比转换为整数类型。

相关问题

stm32f407使用I2C2驱动PCA9685产生16通道PWM的代码

以下是使用STM32F407的I2C2驱动PCA9685产生16通道PWM的代码示例：

#include "stm32f4xx.h"

#define PCA9685_ADDRESS 0x80   // PCA9685 I2C address

// PCA9685 Registers
#define MODE1 0x00
#define PRESCALE 0xFE
#define LED0_ON_L 0x06

I2C_HandleTypeDef hi2c2;

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

  // Set the MODE1 register to put the PCA9685 in sleep mode
  data[0] = MODE1;
  data[1] = 0x10; // Sleep mode
  HAL_I2C_Master_Transmit(&hi2c2, PCA9685_ADDRESS, data, 2, 100);

  // Set the prescaler to generate a 50Hz PWM frequency
  data[0] = PRESCALE;
  data[1] = 0x79; // Prescaler value for 50Hz
  HAL_I2C_Master_Transmit(&hi2c2, PCA9685_ADDRESS, data, 2, 100);

  // Set the MODE1 register to restart the PCA9685
  data[0] = MODE1;
  data[1] = 0x00; // Restart
  HAL_I2C_Master_Transmit(&hi2c2, PCA9685_ADDRESS, data, 2, 100);
}

void PCA9685_SetPWM(uint8_t channel, uint16_t on_time, uint16_t off_time)
{
  uint8_t data[5];

  // Set the ON time for the specified channel
  data[0] = LED0_ON_L + 4 * channel;
  data[1] = on_time & 0xFF;
  data[2] = on_time >> 8;
  HAL_I2C_Master_Transmit(&hi2c2, PCA9685_ADDRESS, data, 3, 100);

  // Set the OFF time for the specified channel
  data[0] = LED0_ON_L + 4 * channel + 2;
  data[1] = off_time & 0xFF;
  data[2] = off_time >> 8;
  HAL_I2C_Master_Transmit(&hi2c2, PCA9685_ADDRESS, data, 3, 100);
}

int main(void)
{
  // Initialize the I2C2 peripheral
  hi2c2.Instance = I2C2;
  hi2c2.Init.ClockSpeed = 400000;
  hi2c2.Init.DutyCycle = I2C_DUTYCYCLE_2;
  hi2c2.Init.OwnAddress1 = 0;
  hi2c2.Init.AddressingMode = I2C_ADDRESSINGMODE_7BIT;
  hi2c2.Init.DualAddressMode = I2C_DUALADDRESS_DISABLE;
  hi2c2.Init.OwnAddress2 = 0;
  hi2c2.Init.GeneralCallMode = I2C_GENERALCALL_DISABLE;
  hi2c2.Init.NoStretchMode = I2C_NOSTRETCH_DISABLE;
  HAL_I2C_Init(&hi2c2);

  // Initialize the PCA9685
  PCA9685_Init();

  // Set the PWM values for channels 0-15
  PCA9685_SetPWM(0, 0, 4095);   // Channel 0 full on
  PCA9685_SetPWM(1, 0, 2047);   // Channel 1 half on
  PCA9685_SetPWM(2, 2047, 0);   // Channel 2 half off
  // ...

  while (1)
  {
    // Main loop
  }
}

在此示例中，我们使用STM32F407的I2C2外设来驱动PCA9685芯片，以产生16个通道的PWM信号。首先，我们需要定义PCA9685芯片的I2C地址以及其寄存器地址。然后，我们定义了两个函数，PCA9685_Init()和PCA9685_SetPWM()，用于初始化PCA9685芯片并设置PWM输出。在主函数中，我们首先初始化I2C2外设，然后调用PCA9685_Init()函数以初始化PCA9685芯片。最后，我们调用PCA9685_SetPWM()函数来设置16个PWM通道的输出。

请注意，此示例中使用的PWM频率为50Hz，可以根据需要进行更改。此外，我们只设置了前三个PWM通道的输出，您可以根据需要设置其他通道的输出。

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
    }
}