标签：输出 adc alter 设定 重载 cti 信号 reload 就会
STM32总共有8个定时器，TIM1,TIM8是16位高级定时器，TIM2,TIM3,TIM4,TIM5是通用定时器，通过设置可以用通用定时器TIM3来产生4路不同占空比的方波（PWM波）。我们使用的IO管脚为TIM3的通道1（PA0.6）、2(PA0.7) 、3（PB.00）、4(PB.01)。
设置步骤及内容：1->设定TIM信号周期、预分频值，分频系数，计数模式 2->根据TIM_TimeBaseInitStruct这个结构体里面的值初始化TIM
3->设定TIM的OC模式 4->TIM输出使能， 5->设定电平跳变值 6-》设定PWM信号的极性 7-》使能TIM信号通道 8-》使能TIM重载寄存器CCRX
9->使能TIM重载寄存器ARR 10-》使能TIM计数器
程序来自野火技术：
/*
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();
}
标签：输出 adc alter 设定 重载 cti 信号 reload 就会
原文地址：https://www.cnblogs.com/Jonhzhu/p/11864843.html
