蓝桥杯嵌入式——第六届决赛-电压测量与互补PWM 信号输出

一、赛题分析

这一届的国赛，整体说来没有什么难度，逻辑以及外设的配置都很easy。但是涉及到一个新的考点，这个需要注意一下，使用高级定时器TIM1输出互补的PWM波，主要是之前没有接触过，但是只要配置出来了，这套题就太简单了。

二、问题总结

唯一遇到的一个问题就是，之前没有配置过高级定时器1，下面给出高级定时器TIM1输出互补的PWM波的程序：

/*** @brief  Configures the different system clocks.* @param  None* @retval None*/
void PWM_RCC_Configuration(void)
{/* TIM1, GPIOA and GPIOB clock enable */RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1 | RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB | RCC_APB2Periph_AFIO, ENABLE);
}/*** @brief  Configures TIM1, TIM3 and TIM4 Pins.* @param  None* @retval None*/
void PWM_GPIO_Configuration(void)
{GPIO_InitTypeDef GPIO_InitStructure;/* GPIOA Configuration: TIM1 Channel2 as alternate function push-pull */GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;GPIO_Init(GPIOA, &GPIO_InitStructure);/* GPIOB Configuration: TIM1 Channel2 as alternate function push-pull */GPIO_InitStructure.GPIO_Pin = GPIO_Pin_14;GPIO_Init(GPIOB, &GPIO_InitStructure);
}void pwm_init(uint16_t period,uint16_t pulse, FunctionalState NewState)
{   TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;TIM_OCInitTypeDef  TIM_OCInitStructure;TIM_DeInit(TIM1);if(NewState == ENABLE){/* System Clocks Configuration */PWM_RCC_Configuration();/* GPIO Configuration */PWM_GPIO_Configuration();/* TIM1 Peripheral Configuration ----------------------------------------*//* Time Base configuration */TIM_TimeBaseStructure.TIM_Prescaler = 5;TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;TIM_TimeBaseStructure.TIM_Period = 12000000 / period;TIM_TimeBaseStructure.TIM_ClockDivision = 0;TIM_TimeBaseStructure.TIM_RepetitionCounter = 4;TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);/* Channel 2 Configuration in PWM mode */TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2;TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;TIM_OCInitStructure.TIM_Pulse = (uint16_t)(12000000 / period / 100 * pulse);TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_Low;TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set;TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCIdleState_Reset;TIM_OC2Init(TIM1, &TIM_OCInitStructure);/* TIM1 counter enable */TIM_Cmd(TIM1, ENABLE);TIM_CtrlPWMOutputs(TIM1, ENABLE);}
}

三、代码

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