SPIDMA发送/接收是非常常见的MCU应用，用于与高速SPI器件通信并提高效率，这个帖子是评测STM32U385RG的SPI1接口，并启用SPI1的DMA发送功能。
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       在上一个帖子中提到，STM32U3的DMA外设名为GPDMA，在ST新出的系列中，任意支持DMA的外设都可以绑定到DMA的任意通道/流/节点上，不像F103和F4系列那样规定通道号，来看看SPI1DMA的配置：
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Normal模式表示每次调用DMA发送函数只会发送一次，Circular模式表示只调用一次DMA发送函数就一直发；在外设所使用的DMA中一般配置外设地址非自增，内存地址可配置为自增或者非自增，内存地址非自增表示DMA发送的数据是同一个数据，也就是内存首地址的数据；源地址和目标地址的数据格式必须一致，都是8位或者16位；只要SPI使用了DMA进行发送或者接收，就必须要把SPI中断和DMA中断都打开，少打开一个都不会正常工作。

SPI初始化代码如下，在ST新系列中加入了一些不太常用的SPI机制，如CS片选引脚空闲等待节拍，Ready模式，因为在大部分场景中片选引脚都由GPIO进行控制，比较少用到SPI外设自带的NSS引脚功能，除非是双MCU通信：
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1. void SPI1_PA5_PA6_PA7_Init(void)
   
2. {
   
3.    
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4.   __HAL_RCC_GPIOA_CLK_ENABLE();
   
5.     __HAL_RCC_SPI1_CLK_ENABLE();
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6.     __HAL_RCC_GPDMA1_CLK_ENABLE();
   
7.    
   
8.     RCC_PeriphCLKInitTypeDef PeriphClkInit = {0};
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9.     GPIO_InitTypeDef GPIO_InitStruct = {0};
   
10.   SPI_AutonomousModeConfTypeDef HAL_SPI_AutonomousMode_Cfg_Struct = {0};
    
11.    
    
12.     PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_SPI1;
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13.   PeriphClkInit.Spi1ClockSelection = RCC_SPI1CLKSOURCE_PCLK2;
    
14.   HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit);
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15.    
    
16.     GPIO_InitStruct.Pin = GPIO_PIN_5|GPIO_PIN_6|GPIO_PIN_7;
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17.     GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    
18.     GPIO_InitStruct.Pull = GPIO_NOPULL;
    
19.     GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
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20.     GPIO_InitStruct.Alternate = GPIO_AF5_SPI1;
    
21.     HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
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22. 
    
23.   hspi1.Instance = SPI1;
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24.   hspi1.Init.Mode = SPI_MODE_MASTER;
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25.   hspi1.Init.Direction = SPI_DIRECTION_2LINES;
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26.   hspi1.Init.DataSize = SPI_DATASIZE_8BIT;
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27.   hspi1.Init.CLKPolarity = SPI_POLARITY_LOW;
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28.   hspi1.Init.CLKPhase = SPI_PHASE_1EDGE;
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29.   hspi1.Init.NSS = SPI_NSS_SOFT;
    
30.   hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_2;
    
31.   hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;
    
32.   hspi1.Init.TIMode = SPI_TIMODE_DISABLE;
    
33.   hspi1.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
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34.   hspi1.Init.CRCPolynomial = 0x7;
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35.   hspi1.Init.NSSPMode = SPI_NSS_PULSE_ENABLE;
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36.   hspi1.Init.NSSPolarity = SPI_NSS_POLARITY_LOW;
    
37.   hspi1.Init.FifoThreshold = SPI_FIFO_THRESHOLD_01DATA;
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38.   hspi1.Init.MasterSSIdleness = SPI_MASTER_SS_IDLENESS_00CYCLE;
    
39.   hspi1.Init.MasterInterDataIdleness = SPI_MASTER_INTERDATA_IDLENESS_00CYCLE;
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40.   hspi1.Init.MasterReceiverAutoSusp = SPI_MASTER_RX_AUTOSUSP_DISABLE;
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41.   hspi1.Init.MasterKeepIOState = SPI_MASTER_KEEP_IO_STATE_ENABLE;
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42.   hspi1.Init.IOSwap = SPI_IO_SWAP_DISABLE;
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43.   hspi1.Init.ReadyMasterManagement = SPI_RDY_MASTER_MANAGEMENT_INTERNALLY;
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44.   hspi1.Init.ReadyPolarity = SPI_RDY_POLARITY_HIGH;
    
45.   HAL_SPI_Init(&hspi1);
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46.     __HAL_SPI_ENABLE(&hspi1);
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47.    
    
48.     HAL_NVIC_SetPriority(SPI1_IRQn, 0, 0);
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49.     HAL_NVIC_EnableIRQ(SPI1_IRQn);
    
50.    
    
51.   HAL_SPI_AutonomousMode_Cfg_Struct.TriggerState = SPI_AUTO_MODE_DISABLE;
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52.   HAL_SPI_AutonomousMode_Cfg_Struct.TriggerSelection = SPI_GRP1_GPDMA_CH0_TCF_TRG;
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53.   HAL_SPI_AutonomousMode_Cfg_Struct.TriggerPolarity = SPI_TRIG_POLARITY_RISING;
    
54.   HAL_SPIEx_SetConfigAutonomousMode(&hspi1, &HAL_SPI_AutonomousMode_Cfg_Struct);
    
55. 
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56.     handle_GPDMA1_Channel1.Instance = GPDMA1_Channel1;
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57.     handle_GPDMA1_Channel1.Init.Request = GPDMA1_REQUEST_SPI1_TX;
    
58.     handle_GPDMA1_Channel1.Init.BlkHWRequest = DMA_BREQ_SINGLE_BURST;
    
59.     handle_GPDMA1_Channel1.Init.Direction = DMA_MEMORY_TO_PERIPH;
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60.     handle_GPDMA1_Channel1.Init.SrcInc = DMA_SINC_INCREMENTED;
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61.     handle_GPDMA1_Channel1.Init.DestInc = DMA_DINC_FIXED;
    
62.     handle_GPDMA1_Channel1.Init.SrcDataWidth = DMA_SRC_DATAWIDTH_BYTE;
    
63.     handle_GPDMA1_Channel1.Init.DestDataWidth = DMA_DEST_DATAWIDTH_BYTE;
    
64.     handle_GPDMA1_Channel1.Init.Priority = DMA_LOW_PRIORITY_LOW_WEIGHT;
    
65.     handle_GPDMA1_Channel1.Init.SrcBurstLength = 1;
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66.     handle_GPDMA1_Channel1.Init.DestBurstLength = 1;
    
67.     handle_GPDMA1_Channel1.Init.TransferAllocatedPort = DMA_SRC_ALLOCATED_PORT0|DMA_DEST_ALLOCATED_PORT0;
    
68.     handle_GPDMA1_Channel1.Init.TransferEventMode = DMA_TCEM_BLOCK_TRANSFER;
    
69.     handle_GPDMA1_Channel1.Init.Mode = DMA_NORMAL;
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70.     HAL_DMA_Init(&handle_GPDMA1_Channel1);
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71. 
    
72.     __HAL_LINKDMA(&hspi1 , hdmatx , handle_GPDMA1_Channel1);
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73. 
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74.     HAL_DMA_ConfigChannelAttributes(&handle_GPDMA1_Channel1, DMA_CHANNEL_NPRIV);
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75.    
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76.     HAL_NVIC_SetPriority(GPDMA1_Channel1_IRQn, 0, 0);
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77.   HAL_NVIC_EnableIRQ(GPDMA1_Channel1_IRQn);
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78. 
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79. }
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80. 
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81. void GPDMA1_Channel1_IRQHandler(void)
    
82. {
    
83.   HAL_DMA_IRQHandler(&handle_GPDMA1_Channel1);
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84. }
    
85. 
    
86. void SPI1_IRQHandler(void)
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87. {
    
88.   HAL_SPI_IRQHandler(&hspi1);
    
89. }

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SPI发送或者发送+接收代码如下：
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1. uint8_t SPI1_PA5_PA6_PA7_Read_Write_Byte(uint8_t TxData)
   
2. {
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3.     uint8_t Rxdata;
   
4.     HAL_SPI_TransmitReceive(&hspi1 , &TxData , &Rxdata , 1 , 1000);      
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5.     return Rxdata;
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6. }
   
7. 
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8. void SPI1_PA5_PA7_Write_Byte(uint8_t TxData)
   
9. {
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10.     HAL_SPI_Transmit(&hspi1 , &TxData , 1 , 1000);
    
11. }

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SPI随时需要调整数据位数为16位或者改回8位：
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1. hspi1.Init.DataSize=SPI_DATASIZE_16BIT;
   
2. HAL_SPI_Init(&hspi1);
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3. 
   
4. hspi1.Init.DataSize=SPI_DATASIZE_8BIT;
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5. HAL_SPI_Init(&hspi1);

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在实际应用中，常常需要修改DMA参数，最常见的就是内存地址自增或者非自增，数据是8位或者16位（Halfword半字）对齐：

1. void SPI1_TX_DMA_Config_PID_MID_HalfWord_Normal()
   
2. {
   
3.     handle_GPDMA1_Channel1.Instance = GPDMA1_Channel1;
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4.     handle_GPDMA1_Channel1.Init.Request = GPDMA1_REQUEST_SPI1_TX;
   
5.     handle_GPDMA1_Channel1.Init.BlkHWRequest = DMA_BREQ_SINGLE_BURST;
   
6.     handle_GPDMA1_Channel1.Init.Direction = DMA_MEMORY_TO_PERIPH;
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7.     handle_GPDMA1_Channel1.Init.SrcInc = DMA_SINC_FIXED;
   
8.     handle_GPDMA1_Channel1.Init.DestInc = DMA_DINC_FIXED;
   
9.     handle_GPDMA1_Channel1.Init.SrcDataWidth = DMA_SRC_DATAWIDTH_HALFWORD;
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10.     handle_GPDMA1_Channel1.Init.DestDataWidth = DMA_DEST_DATAWIDTH_HALFWORD;
    
11.     handle_GPDMA1_Channel1.Init.Priority = DMA_LOW_PRIORITY_LOW_WEIGHT;
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12.     handle_GPDMA1_Channel1.Init.SrcBurstLength = 1;
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13.     handle_GPDMA1_Channel1.Init.DestBurstLength = 1;
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14.     handle_GPDMA1_Channel1.Init.TransferAllocatedPort = DMA_SRC_ALLOCATED_PORT0|DMA_DEST_ALLOCATED_PORT0;
    
15.     handle_GPDMA1_Channel1.Init.TransferEventMode = DMA_TCEM_BLOCK_TRANSFER;
    
16.     handle_GPDMA1_Channel1.Init.Mode = DMA_NORMAL;
    
17. 
    
18.   HAL_DMA_Init(&handle_GPDMA1_Channel1);
    
19.    
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20.     __HAL_LINKDMA(&hspi1 , hdmatx , handle_GPDMA1_Channel1);
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21.    
    
22. }
    
23. 
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24. void SPI1_TX_DMA_Config_PID_MIE_Byte_Normal()
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25. {
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26.     handle_GPDMA1_Channel1.Instance = GPDMA1_Channel1;
    
27.     handle_GPDMA1_Channel1.Init.Request = GPDMA1_REQUEST_SPI1_TX;
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28.     handle_GPDMA1_Channel1.Init.BlkHWRequest = DMA_BREQ_SINGLE_BURST;
    
29.     handle_GPDMA1_Channel1.Init.Direction = DMA_MEMORY_TO_PERIPH;
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30.     handle_GPDMA1_Channel1.Init.SrcInc = DMA_SINC_INCREMENTED;
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31.     handle_GPDMA1_Channel1.Init.DestInc = DMA_DINC_FIXED;
    
32.     handle_GPDMA1_Channel1.Init.SrcDataWidth = DMA_SRC_DATAWIDTH_BYTE;
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33.     handle_GPDMA1_Channel1.Init.DestDataWidth = DMA_DEST_DATAWIDTH_BYTE;
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34.     handle_GPDMA1_Channel1.Init.Priority = DMA_LOW_PRIORITY_LOW_WEIGHT;
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35.     handle_GPDMA1_Channel1.Init.SrcBurstLength = 1;
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36.     handle_GPDMA1_Channel1.Init.DestBurstLength = 1;
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37.     handle_GPDMA1_Channel1.Init.TransferAllocatedPort = DMA_SRC_ALLOCATED_PORT0|DMA_DEST_ALLOCATED_PORT0;
    
38.     handle_GPDMA1_Channel1.Init.TransferEventMode = DMA_TCEM_BLOCK_TRANSFER;
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39.     handle_GPDMA1_Channel1.Init.Mode = DMA_NORMAL;
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40. 
    
41.   HAL_DMA_Init(&handle_GPDMA1_Channel1);
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42.    
    
43.     __HAL_LINKDMA(&hspi1 , hdmatx , handle_GPDMA1_Channel1);
    
44.    
    
45. }

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/ h4 ^$ m2 k) R4 C我这里用SPI1去驱动ST7789的屏幕，使用SPI1的DMA发送功能，因此使用DMA传输函数：

1. HAL_SPI_Transmit_DMA(&hspi1 , pic , num1);

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这里有个ST新系列的SPI波形问题，MOSI脚会在发送结束的时候拉低相当长的一段时间才会恢复高电平。

SPI使用DMA的波形如图：


使用SPI引脚驱动ST7789液晶彩屏：
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