哪些网站可以做商家,网页界面设计体会,莱芜在线董事长,电商网站开发的职责DMA简介
DMA#xff08;Direct Memory Access#xff09;直接存储器存取DMA可以提供外设和存储器或者存储器和存储器之间的高速数据传输#xff0c;无须CPU干预#xff0c;节省了CPU的资源12个独立可配置的通道#xff1a; DMA1#xff08;7个通道#xff09;#xff…DMA简介
DMADirect Memory Access直接存储器存取DMA可以提供外设和存储器或者存储器和存储器之间的高速数据传输无须CPU干预节省了CPU的资源12个独立可配置的通道 DMA17个通道 DMA25个通道 每个通道都支持软件触发和特定的硬件触发STM32F103C8T6 DMA资源DMA17个通道
存储器映像 DMA框图 DMA基本结构 自动重装器转运完成后恢复到初值决定单次转换还是循环转换 M2M0位硬件触发外设到存储器或者存储器到外设1为软件触发存储器到存储器 传输计数器触发一次转运一次计数器减1. *写传输计数器时要先关闭DAM使能 DMA请求
数据宽度与对齐 数据转运DMA
#include DMA.h
uint16_t SIZE;
void myDMA_Init(uint32_t AddrA,uint32_t AddrB,uint16_t Size)
{//开启时钟RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1,ENABLE);SIZE Size;DMA_InitTypeDef DMA_InitStructure;DMA_InitStructure.DMA_BufferSize Size;DMA_InitStructure.DMA_DIR DMA_DIR_PeripheralSRC;//传输方向DMA_InitStructure.DMA_M2M DMA_M2M_Enable;//触发方式DMA_InitStructure.DMA_MemoryBaseAddr AddrB;//目标地址DMA_InitStructure.DMA_MemoryDataSize DMA_MemoryDataSize_Byte;//字节DMA_InitStructure.DMA_MemoryInc DMA_MemoryInc_Enable;DMA_InitStructure.DMA_Mode DMA_Mode_Normal;//是否自动重装DMA_InitStructure.DMA_PeripheralBaseAddr AddrA;//源地址DMA_InitStructure.DMA_PeripheralDataSize DMA_PeripheralDataSize_Byte;//字节DMA_InitStructure.DMA_PeripheralInc DMA_PeripheralInc_Enable;//地址是否递增DMA_InitStructure.DMA_Priority DMA_Priority_Medium;//优先级DMA_Init(DMA1_Channel1,DMA_InitStructure);DMA_Cmd(DMA1_Channel1,DISABLE);}void myDMA_Transmission(void)
{DMA_Cmd(DMA1_Channel1,DISABLE);DMA_SetCurrDataCounter(DMA1_Channel1,SIZE);DMA_Cmd(DMA1_Channel1,ENABLE);while(DMA_GetFlagStatus(DMA1_FLAG_TC1) RESET);DMA_ClearFlag(DMA1_FLAG_TC1);
}
ADC扫描模式DMA
#include ADC.h
uint16_t AD_value[] {0,0,0,0};void AD_Init(void)
{//开启对应时钟RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1,ENABLE);RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1,ENABLE);//GPIO初始化GPIO_InitTypeDef GPIO_InitStructure;GPIO_InitStructure.GPIO_Mode GPIO_Mode_AIN;//模拟输入GPIO_InitStructure.GPIO_Pin GPIO_Pin_0;GPIO_InitStructure.GPIO_Speed GPIO_Speed_50MHz;GPIO_Init(GPIOA,GPIO_InitStructure);//配置ADC的通道配置ADC_RegularChannelConfig(ADC1,ADC_Channel_0,1,ADC_SampleTime_55Cycles5);ADC_RegularChannelConfig(ADC1,ADC_Channel_1,2,ADC_SampleTime_55Cycles5);ADC_RegularChannelConfig(ADC1,ADC_Channel_2,3,ADC_SampleTime_55Cycles5);ADC_RegularChannelConfig(ADC1,ADC_Channel_3,4,ADC_SampleTime_55Cycles5);ADC_InitTypeDef ADC_InitStructure;ADC_InitStructure.ADC_Mode ADC_Mode_Independent;ADC_InitStructure.ADC_ContinuousConvMode DISABLE;ADC_InitStructure.ADC_DataAlign ADC_DataAlign_Right;ADC_InitStructure.ADC_ExternalTrigConv ADC_ExternalTrigConv_None;ADC_InitStructure.ADC_NbrOfChannel 4;ADC_InitStructure.ADC_ScanConvMode ENABLE;ADC_Init(ADC1,ADC_InitStructure);DMA_InitTypeDef DMA_InitStructure;DMA_InitStructure.DMA_BufferSize 4;DMA_InitStructure.DMA_DIR DMA_DIR_PeripheralSRC;//传输方向DMA_InitStructure.DMA_M2M DMA_M2M_Disable;//触发方式DMA_InitStructure.DMA_MemoryBaseAddr (uint16_t)AD_value;//目标地址DMA_InitStructure.DMA_MemoryDataSize DMA_MemoryDataSize_HalfWord;//字节DMA_InitStructure.DMA_MemoryInc DMA_MemoryInc_Enable;DMA_InitStructure.DMA_Mode DMA_Mode_Normal;//是否自动重装DMA_InitStructure.DMA_PeripheralBaseAddr (uint32_t)ADC1-DR;//源地址DMA_InitStructure.DMA_PeripheralDataSize DMA_PeripheralDataSize_HalfWord;DMA_InitStructure.DMA_PeripheralInc DMA_PeripheralInc_Disable;//地址是否递增DMA_InitStructure.DMA_Priority DMA_Priority_Medium;//优先级DMA_Init(DMA1_Channel1,DMA_InitStructure);DMA_Cmd(DMA1_Channel1,ENABLE);ADC_DMACmd(ADC1,ENABLE);ADC_Cmd(ADC1,ENABLE);//ADC校准ADC_ResetCalibration(ADC1);//重置所选ADC校准寄存器。while(ADC_GetResetCalibrationStatus(ADC1) SET);//获取所选ADC重置校准寄存器的状态,重置完成硬件清零ADC_StartCalibration(ADC1);while(ADC_GetCalibrationStatus(ADC1) SET);//获取所选ADC校准状态,校准完成后硬件清零
}uint16_t AD_GetValue(void)//单通道
{DMA_Cmd(DMA1_Channel1,DISABLE);DMA_SetCurrDataCounter(DMA1_Channel1,4);DMA_Cmd(DMA1_Channel1,ENABLE);ADC_SoftwareStartConvCmd(ADC1,ENABLE);//ADC软件触发启动转换。while(DMA_GetFlagStatus(DMA1_FLAG_TC1) RESET);DMA_ClearFlag(DMA1_FLAG_TC1);
}uint16_t AD_GetAppointValue(uint8_t ADC_Channel)//指定通道
{ADC_RegularChannelConfig(ADC1,ADC_Channel,1,ADC_SampleTime_55Cycles5);ADC_SoftwareStartConvCmd(ADC1,ENABLE);//ADC软件触发启动转换。while(ADC_GetFlagStatus(ADC1,ADC_FLAG_EOC) RESET);return ADC_GetConversionValue(ADC1);
}uint16_t AD_GetVoltage(void)
{return (AD_GetValue()/4095)*3.3*100;
}
