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配置 STM32 单片机的定时器时,定时器的功能很好查,但是经常会忘一些东西的使能(比如说我经常忘记配置 IO 口的复用)。现将完整步骤记录如下,以 F407 单片机,定时器 2 通道 2 为例:
首先查数据手册,找到定时器 2 通道 2 对应的 IO 口,为 PA1:
GPIO_InitTypeDef GPIO_InitStructure; TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure; TIM_OCInitTypeDef TIM_OCInitStructure; RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE); // 由于要用到 PA1,因此也要对 GPIO 的时钟使能。 RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE); // 使能定时器 2 GPIO_PinAFConfig(GPIOA, GPIO_PinSource1, GPIO_AF_TIM2); // 这是我经常忘的一句,配置 IO 口的复用功能 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_25MHz; GPIO_Init(GPIOA, &GPIO_InitStructure); TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1; TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up; TIM_TimeBaseInitStructure.TIM_Period = 4; TIM_TimeBaseInitStructure.TIM_Prescaler = 2; TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitStructure); TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Toggle; TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; TIM_OCInitStructure.TIM_Pulse = 2; TIM_OC2Init(TIM2, &TIM_OCInitStructure); TIM_ClearITPendingBit(TIM2, TIM_IT_CC2); // 开启中断之前先清除标志位 TIM_ITConfig(TIM2, TIM_IT_CC2, ENABLE); // 使能比较中断 TIM_Cmd(TIM2, ENABLE); // 使能定时器2
可以看出, 以上过程主要包括 GPIO 的配置、时基单元的配置、输出通道的配置,然后就是一些 xxxConfig函数,真的不要忘。
NVIC 的配置比较简单,只放一下代码
void myNVIC_Init() { NVIC_InitTypeDef NVIC_InitStructure; NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2); NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure); } void TIM2_IRQHandler(void) { if (TIM_GetITStatus(TIM2, TIM_IT_CC2)) { // do something TIM_ClearITPendingBit(TIM2, TIM_IT_CC2); } }
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