STM32 PWM设定输出

/*
函数名：TIM3_GPIO_Config

描述   ：配置TIM3复用输出PWM时用到的IO

输入   ：无

输出   ：  无

调用   ：内部调用
*/
static void TIM3_GPIO_Config(void) 
{
GPIO_InitTypeDef GPIO_InitStructure;

/* TIM3 clock enable */
//PCLK1 经过2倍频后作为TIM3的时钟源等于72MHZ
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);

/* GPIOA and GPIOB clock enable */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB, ENABLE);

/*GPIOA Configuration: TIM3 channel 1 and 2 as alternate function push-pull */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;    // ¸´ÓÃÍÆÍìÊä³ö
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_Init(GPIOA, &GPIO_InitStructure);

/*GPIOB Configuration: TIM3 channel 3 and 4 as alternate function push-pull */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1;

GPIO_Init(GPIOB, &GPIO_InitStructure);
}

/*

*函数名：TIM3_Mode_Config(void)

*描述    ：配置TIM3输出的PWM信号模式，如周期，极性，占空比

*输入    ：无

*输出    ：无

*调用    ：内部调用

*/

static void TIM3_Mode_Config(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;

/* PWM信号电平跳变值 */
u16 CCR1_Val = 500; 
u16 CCR2_Val = 375;
u16 CCR3_Val = 500;
u16 CCR4_Val = 125;

/* -----------------------------------------------------------------------
TIM3 Configuration: generate 4 PWM signals with 4 different duty cycles:
TIM3CLK = 72 MHz, Prescaler = 0x0, TIM3 counter clock = 72 MHz
TIM3 ARR Register = 999 => TIM3 Frequency = TIM3 counter clock/(ARR + 1)
TIM3 Frequency = 72 KHz.
TIM3 Channel1 duty cycle = (TIM3_CCR1/ TIM3_ARR)* 100 = 50%
TIM3 Channel2 duty cycle = (TIM3_CCR2/ TIM3_ARR)* 100 = 37.5%
TIM3 Channel3 duty cycle = (TIM3_CCR3/ TIM3_ARR)* 100 = 25%
TIM3 Channel4 duty cycle = (TIM3_CCR4/ TIM3_ARR)* 100 = 12.5%
----------------------------------------------------------------------- */

/* Time base configuration */    
TIM_TimeBaseStructure.TIM_Period = 999; // 当定时器从0计数到999，即为1000次，为一个定时周期
TIM_TimeBaseStructure.TIM_Prescaler = 0;    // 设置预分频，不预分频即为72MHZ
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1 ;    // 设置时钟分频系数；不分频
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; // 向上计数模式

TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

/* PWM1 Mode configuration: Channel1 */
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;    // 配置PWM模式1
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;    
TIM_OCInitStructure.TIM_Pulse = CCR1_Val;    // 设置跳变值，当计数器计时到这个值时，电平发生跳变
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; // 当定时器计数值小于CCR1_Val时为高电平

TIM_OC1Init(TIM3, &TIM_OCInitStructure);    // 使能通道1

TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Enable);

/* PWM1 Mode configuration: Channel2 */
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = CCR2_Val;    // 

TIM_OC2Init(TIM3, &TIM_OCInitStructure);    // 

TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);

/* PWM1 Mode configuration: Channel3 */
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = CCR3_Val;    // 

TIM_OC3Init(TIM3, &TIM_OCInitStructure);    // 

TIM_OC3PreloadConfig(TIM3, TIM_OCPreload_Enable);

/* PWM1 Mode configuration: Channel4 */
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = CCR4_Val;    // 设置通道4跳变值，输出另外一个占空比的PWM

TIM_OC4Init(TIM3, &TIM_OCInitStructure);    // 使能通道4

TIM_OC4PreloadConfig(TIM3, TIM_OCPreload_Enable);

TIM_ARRPreloadConfig(TIM3, ENABLE);    //  使能TIM3重载寄存器ARR

/* TIM3 enable counter */
TIM_Cmd(TIM3, ENABLE); // 使能定时器3
}

/*

*函数名：TIM3_PWM_Init

*描述   ：TM3输出PWM信号初始化，只有调用这个函数TIM3的4个通道就会有PWM信号输出

*输入   ：无

*输出   ：无

*调用   ：外部调用

*/

void TIM3_PWM_Init(void)
{
TIM3_GPIO_Config();
TIM3_Mode_Config();    
}