关于STM32F1 的SPI 操作讲解已经很普遍了，这里分享一下STM32F1 系列 SPI3 使用DMA 发送和接收，关于SPI3 DMA发送和 接收大多数所都是在中断中 执行的，其实原理一样都需要死循环，等待数据发送完毕后在执行下一步操作。

1. // 初始化SPI3
   
2. void SPI3_Init(void)
   
3. {
   
4.         GPIO_InitTypeDef GPIO_InitStructure;
   
5.         SPI_InitTypeDef SPI_InitStructure;
   
6.         DMA_InitTypeDef DMA_InitStructure;
   
7.         RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA2, ENABLE);
   
8.         RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA|RCC_APB2Periph_GPIOB|RCC_APB2Periph_AFIO, ENABLE);
   
9.         GPIO_PinRemapConfig(GPIO_Remap_SWJ_JTAGDisable , ENABLE); //禁止JTAG功能（保留SWD下载口）
   
10.         RCC_APB1PeriphClockCmd(RCC_APB1Periph_SPI3, ENABLE);
    
11. 
    
12.         GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3 | GPIO_Pin_4 | GPIO_Pin_5;
    
13.         GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;   
    
14.         GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    
15.         GPIO_Init(GPIOB, &GPIO_InitStructure);  
    
16. 
    
17.         GPIO_InitStructure.GPIO_Pin =GPIO_Pin_15; //PA15 =1
    
18.         GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    
19.         GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    
20.         GPIO_Init(GPIOA, &GPIO_InitStructure);
    
21.         PAout(15)=1;
    
22.         SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
    
23.         SPI_InitStructure.SPI_Mode = SPI_Mode_Master;
    
24.         SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;
    
25.         SPI_InitStructure.SPI_CPOL = SPI_CPOL_High;               
    
26.         SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge;
    
27.         SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
    
28.         SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_2;
    
29.         SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
    
30.         SPI_InitStructure.SPI_CRCPolynomial = 7;
    
31.         SPI_Init(SPI3, &SPI_InitStructure);
    
32.         //使能DMA发送
    
33.         DMA_DeInit(DMA2_Channel2);
    
34.         DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)&SPI3->DR;
    
35.         DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;
    
36.         DMA_InitStructure.DMA_BufferSize = 1024;
    
37.         DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
    
38.         DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
    
39.         DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
    
40.         DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
    
41.         DMA_InitStructure.DMA_Mode =   DMA_Mode_Normal;
    
42.         DMA_InitStructure.DMA_Priority = DMA_Priority_Medium;
    
43.         DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
    
44.         DMA_Init(DMA2_Channel2, &DMA_InitStructure);
    
45.         //使能DMA接收
    
46.         DMA_DeInit(DMA2_Channel1);
    
47.         DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)&SPI3->DR;
    
48.         DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
    
49.         DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
    
50.         DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
    
51.         DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
    
52.         DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
    
53.         DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
    
54.         DMA_InitStructure.DMA_Priority = DMA_Priority_Medium;
    
55.         DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
    
56.         DMA_Init(DMA2_Channel1, &DMA_InitStructure);
    
57.         SPI_I2S_DMACmd(SPI3, SPI_I2S_DMAReq_Rx, ENABLE);
    
58.         SPI_I2S_DMACmd(SPI3,SPI_I2S_DMAReq_Tx,ENABLE);
    
59.         SPI_Cmd(SPI3, ENABLE);
    
60. }
    
61. // 速度设置
    
62. void SPI3_SetSpeed(u8 SpeedSet)
    
63. {
    
64.         SPI3->CR1&=0XFFC7;
    
65.         SPI3->CR1|=SpeedSet;
    
66.         SPI_Cmd(SPI3,ENABLE);
    
67. }
    
68. // CPU发送
    
69. uint8_t SPI3_ReadWriteByte(u8 TxData)
    
70. {               
    
71.         while((SPI3->SR&1<<1)==0){;        }
    
72.         SPI3->DR=TxData;                                    
    
73.         while((SPI3->SR&1<<0)==0){;        }         
    
74.         while(SPI3->SR&(1<<7)){;}
    
75.         return SPI3->DR;
    
76. }
    
77. // SPI3 DMA发送
    
78. void DMA_SPI3_TX(uint8_t *buffer,uint16_t len)
    
79. {
    
80.         DMA2->IFCR |=(0xf<<4);
    
81.         DMA2_Channel2->CNDTR=len; //设置要传输的数据长度
    
82.         DMA2_Channel2->CMAR=(u32)buffer; //设置RAM缓冲区地址
    
83.         DMA2_Channel2->CCR|=0x1;
    
84.         while(!(DMA2->ISR&(1<<5))){;}
    
85.         while (SPI_I2S_GetFlagStatus(SPI3, SPI_I2S_FLAG_TXE) == RESET){;}
    
86.         DMA2_Channel2->CCR &=(uint32_t)~0x1;
    
87. }
    
88. // SPI3 DMA 接收
    
89. void DMA_SPI3_RX(uint8_t *buffer,uint16_t len)
    
90. {
    
91.         SPI3->CR1|=SPI_Direction_2Lines_RxOnly;
    
92.         buffer[0] = SPI3->DR;// 读取一次数据
    
93.         DMA2->IFCR |=(0xf<<0);
    
94.         DMA2_Channel1->CNDTR=len; //设置要传输的数据长度
    
95.         DMA2_Channel1->CMAR=(u32)buffer; //设置RAM缓冲区地址
    
96.         DMA2_Channel1->CCR|=0x1;
    
97.         while(!(DMA2->ISR&(1<<1))){;}
    
98.         DMA2_Channel1->CCR &=(uint32_t)~0x1;
    
99.         SPI3->CR1&=~SPI_Direction_2Lines_RxOnly;
    
100. }

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