香帮主,用二个DMA通道进行SPI定时传送的程序设置行吗?
目的:定时发送3个16位数据到SPI接口芯片中
思路:开始时禁止SPI的TXE产生DMA请求
定时到后TIMx发生溢出产生DMA请求，由DMA传送新设置值，使将SPI发送缓冲区空后产生DMA请求。然后由SPI的TXE_DMA进行3个16位数传送。
定时器产生溢出的时间间隔tc(20us<=tc<=100ms)由用户设置
具体如下:
3.1 TIM3设置
/* TIM3CLK = 72 MHz, Prescaler = 0, TIM3 counter clock = 72 MHz */
/* Time base configuration */
TIM_TimeBaseStructure.TIM_Period = 256;
TIM_TimeBaseStructure.TIM_Prescaler = 0;
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);
/* Enable TIM3 DMA */
TIM_DMACmd(TIM3, TIM_DMA_Update, ENABLE);
/* Enable TIM3 counter */
TIM_Cmd(TIM3, ENABLE);
3.2 TIM3对应的DMA通道设置
TIM3的计数溢出DMA通道是通道3，设置如下：
DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)& SPI2 -> CR2;
DMA_InitStructure.DMA_MemoryBaseAddr = (u32) Parallel_Data_Buffer;
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;
DMA_InitStructure.DMA_BufferSize = 1;
DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_ Disable;
DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh;
DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
DMA_Init(DMA_Channel3, &DMA_InitStructure);
/* Enable DMA Channel6 */
DMA_Cmd(DMA_Channel3, ENABLE);
3.3 SPI2对应的DMA通道设置
SPI2的发送缓冲器空（TXE）DMA通道为通道5，设置如下：
DMA_DeInit(DMA_Channel5);
DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)SPI2_DR_Address;
DMA_InitStructure.DMA_MemoryBaseAddr = (u32)SPI1_Buffer_Tx;
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;
DMA_InitStructure.DMA_Priority = DMA_Priority_Low;
DMA_Init(DMA_Channel5, &DMA_InitStructure);
担心程序太长，TIMx、SPI2的初始化设置程序没有贴上。
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楼主
