STM32期末考试答案详解.docx

简述嵌套向量中断控制器（NVIC）的主要特性。答：STM32的嵌套向量中断控制器(NVIC) 管理着包括Cortex-M3核异常等中断，其和ARM处理器核的接口紧密相连，可以实现低延迟的中断处理，并有效地处理晚到的中断。STM32嵌套向量中断控制器(NVIC)的主要特性如下：q 具有43 个可屏蔽中断通道（不包含16 个Cortex-M3 的中断线）。 q 具有16 个可编程的优先等级。 q 可实现低延迟的异常和中断处理。 q 具有电源管理控制。 q 系统控制寄存器的实现。1简述STM32的ADC系统的功能特性。答：STM32的ADC系统的主要功能特性包括如下几个方面：ADC开关控制、ADC时钟、ADC通道选择、ADC的转换模式、中断、模拟看门狗、ADC的扫描模式、ADC的注入通道管理、间断模式、ADC的校准模式、ADC的数据对齐、可编程的通道采样时间、外部触发转换、DMA请求、双ADC模式和温度传感器。2简述STM32的双ADC工作模式。答：在有两个ADC的STM32器件中，可以使用双ADC模式。在双ADC模式里，根据ADC_CR1寄存器中DUALMOD2:0位所选的模式，转换的启动可以是ADC1主和ADC2从的交替触发或同时触发。双ADC工作模式主要包括如下几种：同时注入模式、同时规则模式、快速交替模式、慢速交替模式、交替触发模式和独立模式。1简述STM32的USART的功能特点。、答：STM32的USART为通用同步异步收发器，其可以与使用工业标准NRZ异步串行数据格式的外部设备之间进行全双工数据交换。USART还可以利用分数波特率发生器提供宽范围的波特率选择。STM32的USART支持同步单向通信和半双工单线通信。同时，其也支持LIN(局部互连网)，智能卡协议和IrDA(红外数据)SIR ENDEC规范，以及调制解调器(CTS/RTS)操作。STM32还具备多处理器通信能力。另外，通过多缓冲器配置的DMA方式，还可以实现高速数据通信。1简述STM32的高级控制定时器TIM1的结构。答：STM32提供了一个高级控制定时器(TIM1)。TIM1由一个16位的自动装载计数器组成，它由一个可编程预分频器驱动。TIM1适合多种用途，包含测量输入信号的脉冲宽度，或者产生输出波形。使用定时器预分频器和RCC时钟控制预分频器，可以实现脉冲宽度和波形周期从几个微秒到几个毫秒的调节。高级控制定时器TIM1和通用控制定时器TIMx是完全独立的，它们不共享任何资源，因此可以同步操作。2简述STM32时钟的类型。答：STM32提供了三种不同的时钟源，其都可被用来驱动系统时钟SYSCLK，这三种时钟源分别为：q HSI振荡器时 q HSE振荡器时钟 q PLL时钟这三种时钟源还可以有以下2种二级时钟源：q 32kHz低速内部RC，可以用于驱动独立看门狗和RTC。其中，RTC用于从停机/待机模式下自动唤醒系统。q 32.768kHz低速外部晶振也可用来驱动RTC(RTCCLK)。任一个时钟源都可被独立地启动或关闭，这样可以通过关闭不使用的时钟源来优化整个系统的功耗。1简述DMA控制器的基本功能。答：STM32的DMA 控制器有7个通道，每个通道专门用来管理来自于一个或多个外设对存储器访问的请求。还有一个仲裁器来协调各个DMA 请求的优先权。DMA 控制器和Cortex-M3 核共享系统数据线执行直接存储器数据传输。因此，1 个DMA请求占用至少2 个周期的CPU 访问系统总线时间。为了保证Cortex-M3 核的代码执行的最小带宽，DMA 控制器总是在2 个连续的DMA 请求间释放系统时钟至少1 个周期。NVIC和外部中断:配置中断0（LED绿灯闪1次），中断1（LED蓝灯闪2次），中断2三个中断（LED绿灯闪3次），执行顺序为0-1-2。（默认中断0闪烁的是绿灯）按下按键，绿灯闪(一亮一灭)1次，蓝灯闪2次，然后绿灯闪3次，中断结束。#include stm32l1xx.h#include stdio.h#include discover_board.h#include stm32l_discovery_lcd.h#include stdarg.h/* Private function prototypes -*/void RCC_Configuration(void);void Init_GPIOs (void);void Delay(uint32_t nTime);void USART_Configuration(void);void EXTI_Configuration(void);void NVIC_Configuration(void);static volatile uint32_t TimingDelay;int main(void) /* Configure Clocks for Application need */ RCC_Configuration();SysTick_Config(16000000/ 2000);NVIC_Configuration(); /* Init I/O ports */ Init_GPIOs(); USART_Configuration();EXTI_Configuration();/printf(rnWelcome !rn); while(1) /Delay(20); /printf(rnWelcome !rn); void RCC_Configuration(void) RCC_DeInit(); /* Enable HSI Clock */ RCC_HSICmd(ENABLE); /*! Wait till HSI is ready */ while (RCC_GetFlagStatus(RCC_FLAG_HSIRDY) = RESET) /*RCC_PLLCmd(DISABLE);RCC_PLLConfig(RCC_PLLSource_HSI,RCC_PLLMul_3,RCC_PLLDiv_2);RCC_PLLCmd(ENABLE); */ /*! Wait till PLL is ready */ / while (RCC_GetFlagStatus(RCC_FLAG_PLLRDY) = RESET) / /RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK); RCC_SYSCLKConfig(RCC_SYSCLKSource_HSI); RCC_MSIRangeConfig(RCC_MSIRange_6); RCC_HSEConfig(RCC_HSE_OFF); if(RCC_GetFlagStatus(RCC_FLAG_HSERDY) != RESET ) while(1); /* Enable comparator clock LCD and PWR mngt */ /RCC_APB1PeriphClockCmd(RCC_APB1Periph_LCD | RCC_APB1Periph_PWR, ENABLE); /* Enable ADC clock & SYSCFG */ RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1 | RCC_APB2Periph_SYSCFG | RCC_APB2Periph_USART1 , ENABLE);void Init_GPIOs (void) GPIO_InitTypeDef GPIO_InitStructure; /* Enable GPIOs clock */ RCC_AHBPeriphClockCmd(LD_GPIO_PORT_CLK|USERBUTTON_GPIO_CLK, ENABLE);/* Configure User Button pin as input */ GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_1|GPIO_Pin_2;/USERBUTTON_GPIO_PIN GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN; GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_40MHz; GPIO_Init(USERBUTTON_GPIO_PORT, &GPIO_InitStructure); /* Configure the GPIO_LED pins LD3 & LD4*/ GPIO_InitStructure.GPIO_Pin = LD_GREEN_GPIO_PIN | LD_BLUE_GPIO_PIN; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT; GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz; GPIO_Init(LD_GPIO_PORT, &GPIO_InitStructure); /GPIO_LOW(LD_GPIO_PORT, LD_GREEN_GPIO_PIN); /GPIO_LOW(LD_GPIO_PORT, LD_BLUE_GPIO_PIN);/*Configure the USART1_GPIO_PORT */ /* Connect PA9 to USART1_Tx */ GPIO_PinAFConfig(GPIOA, GPIO_PinSource9, GPIO_AF_USART1); /* Connect PA10 to USART1_Rx*/ GPIO_PinAFConfig(GPIOA, GPIO_PinSource10, GPIO_AF_USART1); /* Configure USART1_Tx and USART1_Rx as alternate function */ GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9 | GPIO_Pin_10; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_40MHz; GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP; GPIO_Init(GPIOA, &GPIO_InitStructure);/* Enable all GPIOs clock */ RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA | RCC_AHBPeriph_GPIOB | RCC_AHBPeriph_GPIOC | RCC_AHBPeriph_GPIOD | RCC_AHBPeriph_GPIOE | RCC_AHBPeriph_GPIOH, ENABLE); void USART_Configuration(void)USART_InitTypeDef USART_InitStructure;USART_ClockInitTypeDef USART_ClockIni;USART_InitStructure.USART_BaudRate = 9600; USART_InitStructure.USART_WordLength = USART_WordLength_8b; USART_InitStructure.USART_StopBits = USART_StopBits_1; USART_InitStructure.USART_Parity = USART_Parity_No ; USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx; USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None; USART_Init(USART1,&USART_InitStructure);USART_ClockIni.USART_Clock = USART_Clock_Disable; USART_ClockIni.USART_CPOL = USART_CPOL_Low; USART_ClockIni.USART_CPHA = USART_CPHA_2Edge; USART_ClockIni.USART_LastBit = USART_LastBit_Disable;USART_ClockInit(USART1,&USART_ClockIni);USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);USART_Cmd(USART1,ENABLE)void EXTI_Configuration()EXTI_InitTypeDef EXTI_InitStructure;/定义PA0,PA1,PA2为外部中断输入通道/ SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOA,EXTI_PinSource0);SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOA,EXTI_PinSource1);SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOA,EXTI_PinSource2);/* Configure EXT1 Line 0 1 2 in interrupt mode trigged on Falling edge */ EXTI_InitStructure.EXTI_Line = EXTI_Line0|EXTI_Line1|EXTI_Line2 ; / PA0 for User button EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt; EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling; EXTI_InitStructure.EXTI_LineCmd = ENABLE; EXTI_Init(&EXTI_InitStructure);void NVIC_Configuration()NVIC_InitTypeDef NVIC_InitStructure; #ifdef VECT_TAB_RAM /C/C+ CompilerPreprocessorDefined symbolsVECT_TAB_RAM NVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0); /RAM #else /VECT_TAB_RAM NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x0);/Flash #endif /NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);/* Enable and set EXTI0 Interrupt to the lowest priority */ NVIC_InitStructure.NVIC_IRQChannel = EXTI0_IRQn ; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 2; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure); NVIC_InitStructure.NVIC_IRQChannel = EXTI1_IRQn ; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure); NVIC_InitStructure.NVIC_IRQChannel = EXTI2_IRQn ; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure); void Delay(uint32_t nTime) TimingDelay = nTime; while(TimingDelay != 0);void TimingDelay_Decrement(void) if (TimingDelay != 0x00) TimingDelay-; int fputc(int ch,FILE *f)USART_SendData(USART1,(unsigned char)ch);while(USART_GetFlagStatus(USART1,USART_FLAG_TC)=RESET);return ch;#include stm32l1xx_it.h#include main.hvoid NMI_Handler(void)void HardFault_Handler(void) /* Go to infinite loop when Hard Fault exception occurs */ while (1) void MemManage_Handler(void) /* Go to infinite loop when Memory Manage exception occurs */ while (1) void BusFault_Handler(void)/* Go to infinite loop when Bus Fault exception occurs */ while (1) void UsageFault_Handler(void) /* Go to infinite loop when Usage Fault exception occurs */ while (1) void SVC_Handler(void)void DebugMon_Handler(void)void PendSV_Handler(void)void SysTick_Handler(void) TimingDelay_Decrement();void DMA1_Channel1_IRQHandler (void)void RTC_WKUP_IRQHandler(void)void EXTI0_IRQHandler(void)int i;GPIO_TOGGLE(LD_GPIO_PORT ,LD_GREEN_GPIO_PIN );for(i=0;i500000;i+)GPIO_TOGGLE(LD_GPIO_PORT ,LD_GREEN_GPIO_PIN );for(i=0;i500000;i+)EXTI_GenerateSWInterrupt(EXTI_Line1);EXTI_ClearFlag(EXTI_Line0);void EXTI1_IRQHandler(void)int i;GPIO_TOGGLE(LD_GPIO_PORT ,LD_BLUE_GPIO_PIN );for(i=0;i500000;i+)GPIO_TOGGLE(LD_GPIO_PORT ,LD_BLUE_GPIO_PIN );for(i=0;i500000;i+)GPIO_TOGGLE(LD_GPIO_PORT ,LD_BLUE_GPIO_PIN );for(i=0;i500000;i+)GPIO_TOGGLE(LD_GPIO_PORT ,LD_BLUE_GPIO_PIN );for(i=0;i500000;i+)EXTI_GenerateSWInterrupt(EXTI_Line2);EXTI_ClearFlag(EXTI_Line1);void EXTI2_IRQHandler(void)int i;GPIO_TOGGLE(LD_GPIO_PORT ,LD_GREEN_GPIO_PIN );for(i=0;i500000;i+)GPIO_TOGGLE(LD_GPIO_PORT ,LD_GREEN_GPIO_PIN );for(i=0;i500000;i+)GPIO_TOGGLE(LD_GPIO_PORT ,LD_GREEN_GPIO_PIN );for(i=0;i500000;i+)GPIO_TOGGLE(LD_GPIO_PORT ,LD_GREEN_GPIO_PIN );for(i=0;i500000;i+)GPIO_TOGGLE(LD_GPIO_PORT ,LD_GREEN_GPIO_PIN );for(i=0;i500000;i+)GPIO_TOGGLE(LD_GPIO_PORT ,LD_GREEN_GPIO_PIN );for(i=0;i500000;i+)EXTI_ClearFlag(EXTI_Line2);/*void PPP_IRQHandler(void) */ * （配置的两个定时器通道的中断请求的时间间隔分别为1秒和2秒）红红每隔1秒闪烁1次，绿灯每隔2秒闪烁1次。#include stm32l1xx.h#include stdio.h/* 自定义同义关键字 -*/* 自定义参数宏 -*/* 自定义函数宏 -*/* 自定义变量 -*/uint16_t CCR1_Val =2500; /*初始化输出比较通道1计数周期变量*/uint16_t CCR1_Val =5000;uint16_t CCR2_Val =1250; /*/uint16_t CCR2_Val =2500; /*/uint16_t CCR3_Val =10000; /*/uint16_t CCR4_Val =5000; /*/* 自定义函数声明 -*/void RCC_Configuration(void);void GPIO_Configuration(void);void NVIC_Configuration(void);void TIM_Configuration(void);* 函数名 : main* 函数描述 : 主函数* 输入参数 : 无int main(void) /* 设置系统时钟 */ RCC_Configuration();/* 设置NVIC */ NVIC_Configuration();/* 设置GPIO端口 */ GPIO_Configuration();/* 设置 TIM */ TIM_Configuration(); while (1);* 函数名: RCC_Configuration* 函数描述 : 设置系统各部分时钟* 输入参数 : 无void RCC_Configuration(void)/* 定义枚举类型变量 HSEStartUpStatus */ErrorStatus HSEStartUpStatus; /* 复位系统时钟设置*/ RCC_DeInit(); /* 开启HSE*/ RCC_HSEConfig(RCC_HSE_ON); /* 等待HSE起振并稳定*/ HSEStartUpStatus = RCC_WaitForHSEStartUp();/* 判断HSE起是否振成功，是则进入if()内部 */ if(HSEStartUpStatus = SUCCESS) /* 选择HCLK（AHB）时钟源为SYSCLK 1分频 */ RCC_HCLKConfig(RCC_SYSCLK_Div1); /* 选择PCLK2时钟源为 HCLK（AHB） 1分频 */ RCC_PCLK2Config(RCC_HCLK_Div1); /* 选择PCLK1时钟源为 HCLK（AHB） 2分频 */ RCC_PCLK1Config(RCC_HCLK_Div2); /* 设置FLASH延时周期数为2 */ FLASH_SetLatency(FLASH_Latency_1); /* 使能FLASH预取缓存 */ FLASH_PrefetchBufferCmd(ENABLE); /* 选择锁相环（PLL）时钟源为HSE 2分频，倍频数为8，则PLL输出频率为 8MHz * 4 = 32MHz */ RCC_PLLConfig(RCC_PLLSource_HSE, RCC_PLLMul_8,RCC_PLLDiv_2); /* 使能PLL */ RCC_PLLCmd(ENABLE); /* 等待PLL输出稳定 */ while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) = RESET); /* 选择SYSCLK时钟源为PLL */ RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK); /* 等待PLL成为SYSCLK时钟源 */ while(RCC_GetSYSCLKSource() != 0x08); /* 打开APB2总线上的GPIOA时钟*/RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOB , ENABLE); * 函数名 : GPIO_Configuration* 函数描述 : 设置各GPIO端口功能void GPIO_Configuration(void)/* 定义GPIO初始化结构体 GPIO_InitStructure */ GPIO_InitTypeDef GPIO_InitStructure; /* 设置PA.0,PA.1,PA.2为浮空输入（EXTI Line0）*/ GPIO_InitStructure.GPIO_Pin =GPIO_Pin_6|GPIO_Pin_7; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT; GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL; GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_40MHz; GPIO_Init(GPIOB , &GPIO_InitStructure);* 函数名 : NVIC_Configuration* 函数描述 : 设置NVIC参数void TIM_Configuration(void)/*定襎IM_TimeBase初始化结构体?/TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;/*定义TIM_OCInit初始化结构体*/TIM_OCInitTypeDef TIM_OCInitStructure;/*技术重载值为65535，预分频值为16000，时钟分割0，向上计数模式*/TIM_TimeBaseStructure.TIM_Period=65535;TIM_TimeBaseStructure.TIM_Prescaler= 0;TIM_TimeBaseStructure.TIM_ClockDivision=0;TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up;TIM_TimeBaseInit(TIM2,&TIM_TimeBaseStructure);/*设置预分频值，立即装入*/TIM_PrescalerConfig(TIM2,3199,TIM_PSCReloadMode_Immediate);/*设置OC1，OC2通道，工作模式为计数器模式，使能比较匹配输出极性，时钟分割0，向上计数模式*/TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_Timing;TIM_OCInitStructure.TIM_OutputState=TIM_OutputState_Enable;TIM_OCInitStructure.TIM_OCPolarity=TIM_OCPolarity_High;TIM_OCInitStructure.TIM_Pulse=CCR1_Val;TIM_OC1Init(TIM2,&TIM_OCInitStructure);TIM_OCInitStructure.TIM_Pulse=CCR2_Val;TIM_OC2Init(TIM2,&TIM_OCInitStructure);/*TIM_OCInitStructure.TIM_Pulse=CCR3_Val;TIM_OC3Init(TIM2,&TIM_OCInitStructure);TIM_OCInitStructure.TIM_Pulse=CCR4_Val;TIM_OC4Init(TIM2,&TIM_OCInitStructure);*/*禁止预装载寄存器*/TIM_OC1PreloadConfig(TIM2,TIM_OCPreload_Disable);TIM_OC2PreloadConfig(TIM2,TIM_OCPreload_Disable);/TIM_OC3PreloadConfig(TIM2,TIM_OCPreload_Disable);/TIM_OC4PreloadConfig(TIM2,TIM_OCPreload_Disable);/*使能TIM中断*/TIM_ITConfig(TIM2,TIM_IT_CC1 | TIM_IT_CC2,ENABLE );/*启动TIM计数*/TIM_Cmd(TIM2,ENABLE);* 函数名 : NVIC_Configuration* 函数描述 : 设置NVIC参数void NVIC_Configuration(void)/* 定义NVIC初始化结构体 NVIC_InitStructure */NVIC_InitTypeDef NVIC_InitStructure;/* #ifdef.#else.#endif结构的作用是根据预编译条件决定中断向量表起始地址*/ #ifdef VECT_TAB_RAM /* 中断向量表起始地址从 0x20000000 开始 */ NVIC_SetVectorTable(NVIC_VectTab_RAM , 0x0); #else /* VECT_TAB_FLASH */ /* 中断向量表起始地址从 0x80000000 开始 */ NVIC_SetVectorTable(NVIC_VectTab_FLASH , 0x0); #endif /* 选择NVIC优先级分组2 */ NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0); /* 使能EXIT 0通道 ，2级先占优先级 ，0级次占优先级 */ 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);#include stm32l1xx_it.h#include stdio.hextern uint16_t CCR1_Val; /*声明输出比较通道1计数周期变量*/extern uint16_t CCR2_Val;extern uint16_t CCR3_Val;extern uint16_t CCR4_Val;void NMI_Handler(void)void HardFault_Handler(void) /* Go to infinite loop when Hard Fault exception occurs */ while (1) void MemManage_Handler(void) /* Go to infinite loop when Memory Manage exception occurs */ while (1) void BusFault_Handler(void) /* Go to infinite loop when Bus Fault exception occurs */ while (1) void UsageFault_Handler(void) /* Go to infinite loop when Usage Fault exception occurs */ while (1) void SVC_Handler(void)void DebugMon_Handler(void)void PendSV_Handler(void)void SysTick_Handler(void) / TimingDelay_Decrement();void DMA1_Channel1_IRQHandler (void)void RTC_WKUP_IRQHandler(void)void TIM2_IRQHandler(void)uint16_t capture=0;/*当前捕获计数值局部变量*/*TIM时钟=32M，分频数=1599+1，TIM2 counter clock=10khz CC1更新率=TIM2counter clock/CCRX_Val*/if(TIM_GetITStatus(TIM2,TIM_IT_CC1)!=RESET)GPIO_WriteBit(GPIOB,GPIO_Pin_6,(BitAction)(1-GPIO_ReadOutputDataBit(GPIOB,GPIO_Pin_6);/*读出当前计数值*/capture=TIM_GetCapture1(TIM2);/*根据当前计数值更新输出捕获寄存器*/TIM_SetCompare1(TIM2,capture+CCR1_Val);TIM_ClearITPendingBit(TIM2,TIM_IT_CC1);else if(TIM_GetITStatus(TIM2,TIM_IT_CC2)!=RESET)GPIO_WriteBit(GPIOB,GPIO_Pin_7,(BitAction)(1-GPIO_ReadOutputDataBit(GPIOB,GPIO_Pin_7);capture=TIM_GetCapture2(TIM2);TIM_SetCompare2(TIM2,capture+CCR2_Val);TIM_ClearITPendingBit(TIM2,TIM_IT_CC2);/else if(TIM_GetITStatus(TIM2,TIM_IT_CC3)!=RESET)/GPIO_WriteBit(GPIOA,GPIO_Pin_6,(BitAction)(1-GPIO_ReadOutputDataBit(GPIOA,GPIO_Pin_6);/capture=TIM_GetCapture3(TIM2);/TIM_SetCompare3(TIM2,capture+CCR3_Val);/TIM_ClearITPendingBit(TIM2,TIM_IT_CC3);/else if(TIM_GetITStatus(TIM2,TIM_IT_CC4)!=RESET)/GPIO_WriteBit(GPIOA,GPIO_Pin_7,(BitAction)(1-GPIO_ReadOutputDataBit(GPIOA,GPIO_Pin_7);/capture=TIM_GetCapture4(TIM2);/TIM_SetCompare4(TIM2,capture+CCR4_Val);/TIM_ClearITPendingBit(TIM2,TIM_IT_CC4);/ * 按键按一下，LED3和LED4灯亮，松开按键，再次按下按键，LED3和LED4灯灭。* 使用GPIO和SysTick定时器实现按键扫描*/ #include stm32l1xx.h#include stdio.h#include discover_board.h#include stm32l_discovery_lcd.h/* Private function prototypes */void RCC_Configuration(void);/*系统时钟设置*/void Init_GPIOs (void);/*GPIO端口设置*/void Delay(uint32_t nTime);static volatile uint