基于循环DMA+PWM实现正玄波

小鱼儿 2021-12-10 20:27 542阅读 0赞

最近看群里大家在讨论PWM，想起以前写的PWM模拟正玄波的代码，拿出来分享下。

其实也很简单，我就把我做的思路讲解下，期望能帮助到用到的人吧。

首先说下要求：

1、16点的正玄波，当然这个是不是重点；

2、正玄波周期可调；

3、正玄波幅度可调；

实现思路：

一、利用matlab仿真，计算出16点的正玄波基础数据

static  const   float   c_fSinStandardValue[]={
        0.0,631.4276634 ,1166.726189 ,1524.401229 ,1650 ,1524.401229 ,1166.726189 ,631.4276634 ,
        0.0,-631.4276634,-1166.726189,-1524.401229,-1650,-1524.401229,-1166.726189,-631.4276634,
    };

这16个数据点适合周期无关的。

二、怎么显示负半波

由于我们的板子没有负压，因此我要想实现输出负压，只能提供直流分量，因此我在算法里面把直流分量

提高到了1.65V。

三、根据用户输入频率和幅度计算周期和占空比

static  bool    calculate_pwm_ratio(uint16_t    hwSelectSinV_mV,uint32_t    wSelectSinF_Hz)
    {
        uint8_t     i=0;
        uint16_t    hwPwmT=0;
    
        if(!wSelectSinF_Hz){
            return false;
        }
        
        hwPwmT = TIMX_CLK/(wSelectSinF_Hz*DMA_BUFFER_SIZE);
        for(i=0;i<DMA_BUFFER_SIZE;i++){
            s_hwDmaBuffer[i] = (uint16_t)(((hwSelectSinV_mV/3300.0)*c_fSinStandardValue[i]+1650.0)*hwPwmT/3300.0);
            if(s_hwDmaBuffer[i]>hwPwmT){
                s_hwDmaBuffer[i]=hwPwmT;
            }
            if(s_hwDmaBuffer[i]){
                s_hwDmaBuffer[i] -=1;
            }
        }
        return true;
    }

四、就是底层硬件驱动了

DMA驱动：

static  bool    pwm_dma(uint8_t  chSelectChannel)
    {
        DMA_Cmd(DMA1_Channel5,DISABLE);
        DMA_DeInit(DMA1_Channel7);
        DMA_ITConfig(DMA1_Channel5,DMA_IT_TC|DMA_IT_HT|DMA_IT_TE,DISABLE);
        do{
            DMA_InitTypeDef     tDMA_InitlStructure;
            DMA_StructInit( &tDMA_InitlStructure );
            
            switch(chSelectChannel){
                case 1:
                    tDMA_InitlStructure.DMA_PeripheralBaseAddr  =   (uint32_t)&TIM4->CCR1;
                    break;
                case 2:
                    tDMA_InitlStructure.DMA_PeripheralBaseAddr  =   (uint32_t)&TIM4->CCR2;
                    break;
                case 3:
                    tDMA_InitlStructure.DMA_PeripheralBaseAddr  =   (uint32_t)&TIM4->CCR3;
                    break;
                default:
                    return false;
            }
            tDMA_InitlStructure.DMA_MemoryBaseAddr      =   (uint32_t)s_hwDmaBuffer;
            tDMA_InitlStructure.DMA_DIR                 =   DMA_DIR_PeripheralDST;
            tDMA_InitlStructure.DMA_BufferSize          =   DMA_BUFFER_SIZE;
            tDMA_InitlStructure.DMA_PeripheralInc       =   DMA_PeripheralInc_Disable;
            tDMA_InitlStructure.DMA_MemoryInc           =   DMA_MemoryInc_Enable;
            tDMA_InitlStructure.DMA_PeripheralDataSize  =   DMA_PeripheralDataSize_HalfWord;
            tDMA_InitlStructure.DMA_MemoryDataSize      =   DMA_MemoryDataSize_HalfWord;
            tDMA_InitlStructure.DMA_Mode                =   DMA_Mode_Circular;
            tDMA_InitlStructure.DMA_Priority            =   DMA_Priority_High;
            tDMA_InitlStructure.DMA_M2M                 =   DMA_M2M_Disable;
            
            DMA_ClearFlag( DMA1_IT_TC7 );
            DMA_Init(DMA1_Channel7, &tDMA_InitlStructure);
        }while(0);
        DMA_Cmd(DMA1_Channel7,ENABLE);
        return true;
    }

IO口驱动：

void    user_pwm_init(void)
    {
        RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB | RCC_APB2Periph_AFIO, ENABLE);
        RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);
        RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1,ENABLE);
        
        do{
            static  const   GPIO_InitTypeDef c_tGPIO_InitStructure={
                .GPIO_Pin   = GPIO_Pin_8 | GPIO_Pin_7 | GPIO_Pin_6,
                .GPIO_Mode  = GPIO_Mode_AF_PP,
                .GPIO_Speed = GPIO_Speed_50MHz,
            };
            GPIO_Init(GPIOB, (GPIO_InitTypeDef*)&c_tGPIO_InitStructure);
        }while(0);
        
        
        //NVIC_SetPriority(DMA1_Channel5_IRQn, 0);
        //NVIC_EnableIRQ(DMA1_Channel5_IRQn);
        
        
    }

PWM驱动：

bool    user_pwm_cfg(uint16_t   hwSetV_mV,uint16_t   hwSetF_Hz,uint8_t  chSelectChannel)
    {
    	//GPIO_InitTypeDef GPIO_InitStructure;
    	TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
    	//TIM_OCInitTypeDef  TIM_OCInitStructure;
    
        TIM_Cmd(TIM4, DISABLE);
        
        if(!hwSetF_Hz){
            return false;
        }
        
        if(!pwm_dma(chSelectChannel)){
            return false;
        }
        
        if(!calculate_pwm_ratio(hwSetV_mV,hwSetF_Hz)){
            return false;
        }
               
    	/* 第1步：打开GPIOB RCC_APB2Periph_AFIO 的时钟	*/
    	//RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB | RCC_APB2Periph_AFIO, ENABLE);
        
        /*
        do{
            static  const   GPIO_InitTypeDef c_tGPIO_InitStructure={
                .GPIO_Pin   = GPIO_Pin_6 |GPIO_Pin_7,
                .GPIO_Mode  = GPIO_Mode_Out_PP,
                .GPIO_Speed = GPIO_Speed_50MHz
            };
            GPIO_Init(GPIOB, (GPIO_InitTypeDef*)&c_tGPIO_InitStructure);
            GPIO_ResetBits(GPIOB, GPIO_Pin_6);
            GPIO_ResetBits(GPIOB, GPIO_Pin_7);
        }while(0);
        */
        
    	/* 配置GPIO为复用推挽输出模式 */
        /*
        do{
            static  const   GPIO_InitTypeDef c_tGPIO_InitStructure={
                .GPIO_Pin   = GPIO_Pin_8,
                .GPIO_Mode  = GPIO_Mode_AF_PP,
                .GPIO_Speed = GPIO_Speed_50MHz,
            };
            GPIO_Init(GPIOB, (GPIO_InitTypeDef*)&c_tGPIO_InitStructure);
        }while(0);
        */
    
    	/* 使能TIM4的时钟 */
    	//RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);
        do{
            hwSetF_Hz = TIMX_CLK/(hwSetF_Hz*DMA_BUFFER_SIZE);
            if(hwSetF_Hz<=1){
                return false;
            }
            TIM_TimeBaseStructure.TIM_Period         = hwSetF_Hz - 1;	/* TIM_Period = TIM3 ARR Register */
            TIM_TimeBaseStructure.TIM_Prescaler      = 0;
            TIM_TimeBaseStructure.TIM_ClockDivision  = 0;
            TIM_TimeBaseStructure.TIM_CounterMode    = TIM_CounterMode_Up;
            
            TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure);
        }while(0);
    
    	/* PWM1 Mode configuration: Channel1 */
        do{
            TIM_OCInitTypeDef  tTIM_OCInitStructure={
                .TIM_OCMode = TIM_OCMode_PWM1,
                .TIM_OutputState = TIM_OutputState_Enable,
                //.TIM_Pulse = (TIM_TimeBaseStructure.TIM_Period * hwSetV_mV) / SYS_PWM_MAX_V,	/* 改变占空比 */
                .TIM_Pulse =0,	/* 改变占空比 */
                .TIM_OCPolarity = TIM_OCPolarity_High
            };
    
            TIM_OC1Init(TIM4, (TIM_OCInitTypeDef*)&tTIM_OCInitStructure);
            TIM_OC1PreloadConfig(TIM4, TIM_OCPreload_Disable); 
    
            TIM_OC2Init(TIM4, (TIM_OCInitTypeDef*)&tTIM_OCInitStructure);
            TIM_OC2PreloadConfig(TIM4, TIM_OCPreload_Disable);
    
            TIM_OC3Init(TIM4, (TIM_OCInitTypeDef*)&tTIM_OCInitStructure);
            TIM_OC3PreloadConfig(TIM4, TIM_OCPreload_Disable);
    
            TIM_OC4Init(TIM4, (TIM_OCInitTypeDef*)&tTIM_OCInitStructure);
            TIM_OC4PreloadConfig(TIM4, TIM_OCPreload_Disable);
            switch(chSelectChannel){
                case 1:
                    //TIM_OC1Init(TIM4, (TIM_OCInitTypeDef*)&tTIM_OCInitStructure);
                    TIM_OC1PreloadConfig(TIM4, TIM_OCPreload_Enable); 
                    break;
                case 2:
                    //TIM_OC2Init(TIM4, (TIM_OCInitTypeDef*)&tTIM_OCInitStructure);
                    TIM_OC2PreloadConfig(TIM4, TIM_OCPreload_Enable);
                    break;
                case 3:
                    //TIM_OC3Init(TIM4, (TIM_OCInitTypeDef*)&tTIM_OCInitStructure);
                    TIM_OC3PreloadConfig(TIM4, TIM_OCPreload_Enable);
                    break;
                default:
                    return false;
            }
    
            //TIM_OC4Init(TIM4, (TIM_OCInitTypeDef*)&tTIM_OCInitStructure);
            //TIM_OC4PreloadConfig(TIM4, TIM_OCPreload_Disable);
        }while(0);
        
    	TIM_ARRPreloadConfig(TIM4, ENABLE);
        
        //DMA
        do{
            //TIM_DMAConfig(TIM4,TIM_DMABase_CCR3,TIM_DMABurstLength_2Bytes);
            TIM_DMACmd(TIM4,TIM_DMA_Update,ENABLE);
        }while(0);
        
        
        //DMA_Cmd(DMA1_Channel5,ENABLE);
        
    	/* TIM4 enable counter */
    	TIM_Cmd(TIM4, ENABLE);
        
        TIM_CtrlPWMOutputs(TIM4, ENABLE);
        
        return true;
    }

输出波形，经过一个低通滤波器后，输出了正玄波。

源码下载地址：[https://download.csdn.net/download/wuhenyouyuyouyu/11339564][https_download.csdn.net_download_wuhenyouyuyouyu_11339564]

[https_download.csdn.net_download_wuhenyouyuyouyu_11339564]: https://download.csdn.net/download/wuhenyouyuyouyu/11339564