STM32

在STM32H7 MCU上配置DMA请求多路复用器

2019-07-14 17:58发布

站内问答 / STM32/STM8
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我最近使用新生产的SM32H7 MCU，目前正在将一些旧代码迁移到它们（我想看看他们如何处理一些需要更高速度的应用程序）。H7具有DMA请求多路复用器，在我曾经使用的旧F7，F4或F3中不存在。在后一种模型中，通过向DMA_x Stream_y控制寄存器输入正确的值来完成DMA通道映射。例如DMA2_Stream3->CR |= (0x3 << DMA_SxCR_CHSEL_Pos);将为DM2 Stream3选择第三个通道（在F7 MCU的情况下，这将对应于SPI1 TX DMA请求： 1.png 据我所知，DMA流到DMA通道映射不再是“硬连线”，它可以在H7系列中手动重新配置。正如手册所述，必须使用DMAMux1将DMA请求线路连接到DMA通道。不幸的是，DMAMUX配置在参考手册中描述得相当差。我还没有意识到如何准确DMA流，外设和DMA通道通过多路复用器互连。下面是一段代码，理想情况下应该是
  • 设置SPI1。
  • 设置DMA。

  • 启用DMA流以进行SPI TX传输
    1. <font size="4">RCC->AHB4ENR |= RCC_AHB4ENR_GPIOAEN;   // Enable usage of GPIOA
    2. RCC->APB2ENR |= RCC_APB2ENR_SPI1EN;

    4. GPIOA->MODER &= ~GPIO_MODER_MODER5;
    5. GPIOA->MODER |= GPIO_MODER_MODER5_1;   // Alternate function for SPI1 SCK on PA5
    6. GPIOA->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR5;   // High Speed on PA5
    7. GPIOA->AFR[0] |= (0x05 << 5 * 4);   // AFRL selected AF5 (SPI1 SCK) for PA5

    9. GPIOA->MODER &= ~GPIO_MODER_MODER6;
    10. GPIOA->MODER |= GPIO_MODER_MODER6_1;   // Alternate function for SPI1 MISO on PA6
    11. GPIOA->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR6;   // High Speed on PA6
    12. GPIOA->AFR[0] |= (0x05 << 6 * 4);   // AFRL selected AF5 (SPI1 MISO) for PA6

    14. GPIOA->MODER &= ~GPIO_MODER_MODER7;
    15. GPIOA->MODER |= GPIO_MODER_MODER7_1;   // Alternate function for SPI1 MOSI on PA7
    16. GPIOA->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR7;   // High Speed on PA7
    17. GPIOA->AFR[0] |= (0x05 << 7 * 4);   // AFRL selected AF5 (SPI1 MOSI) for PA7

    19. GPIOA->MODER &= ~GPIO_MODER_MODER4;
    20. GPIOA->MODER |= GPIO_MODER_MODER4_1;   // Alternate function for SPI1 NSS on PA7
    21. GPIOA->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR4;   // High Speed on PA7
    22. GPIOA->AFR[0] |= (0x05 << 4 * 4);   // AFRL selected AF5 (SPI1 NSS) for PA7

    24. GPIOA->PUPDR |= GPIO_PUPDR_PUPDR4_0;  // Ensure all pull up pull down resistors are enabled
    25. GPIOA->PUPDR &= ~GPIO_PUPDR_PUPDR5;   // Ensure all pull up pull down resistors are disabled
    26. GPIOA->PUPDR &= ~GPIO_PUPDR_PUPDR6;   // Ensure all pull up pull down resistors are disabled
    27. GPIOA->PUPDR &= ~GPIO_PUPDR_PUPDR7;   // Ensure all pull up pull down resistors are disabled

    29. SPI1->CFG1 = (1u << SPI_CFG1_MBR_Pos) | // Master baud rate: master clock / 2
    30.                  (7u << SPI_CFG1_CRCSIZE_Pos) | // Length of CRC frame
    31.                  SPI_CFG1_TXDMAEN | SPI_CFG1_RXDMAEN | // Enable RX/TX DMA
    32.                  (7u << SPI_CFG1_FTHLV_Pos) | // FIFO threshold level
    33.                  (7u << SPI_CFG1_DSIZE_Pos) //Number of bits in at single SPI data frame
    34.                  ;

    36. SPI1->CFG2 = SPI_CFG2_SSOE | // SS output enable
    37.              SPI_CFG2_MASTER // SPI Master
    38.              ;      

    40. RCC->AHB1ENR |= RCC_AHB1ENR_DMA2EN;   // DMA2 clock enable;

    42. DMA2_Stream3->CR = 0u;
    43. DMA2_Stream3->PAR = (uint32_t) &(SPI1->TXDR);
    44. DMA2_Stream3->M0AR = (uint32_t) &(Data_Buffer[0]);
    45. DMA2_Stream3->CR |= (1u << DMA_SxCR_DIR_Pos);
    46. DMA2_Stream3->CR |= DMA_SxCR_MINC;
    47. DMA2_Stream3->CR |= DMA_SxCR_PL;
    48. DMA2_Stream3->NDTR = 1000;

    50. // 5. Use DMAMux1 to route a DMA request line to the DMA channel.
    51. DMAMUX1_Channel0->CCR  = (37u << DMAMUX_CxCR_DMAREQ_ID_Pos);

    53. SPI1->CR1 |= SPI_CR1_SPE;
    54. DMA2_Stream3->CR |= DMA_SxCR_EN;</font>
    复制代码    此代码编译，我可以将其上传到STM32H753ZIT6 MCU。完整的代码还有PLL设置，它不包含在上面的代码段中（PLL初始化工作得很好，因为我能够探测MCO引脚上的400 MHz系统时钟）。DMA多路复用器设置无疑是不完整的。我只选择了一个适当的多路复用器输入资源。我甚至不确定多路复用器通道是否正确（或者他们的选择在H7 MCU中是否是任意的）。所以我的问题是为SPI TX传输设置DMA多路复用器的正确方法是什么？如果我可以运行这个MWE，我或多或少能够完成我的其余代码的迁移。
    所以，我一直在尝试关注user9403409的建议，但不幸的是，我无法走得太远。我仍然无法让SPI在H7系列微控制器上通过DMA工作。现在我可以让SPI在没有H7的DMA的情况下正常工作：
    1. <font size="4">#include "stm32h7xx.h"

    3. #include <stdio.h>
    4. #include <stdlib.h>
    5. #include <string.h>

    7. static void InitializeMCO(void);
    8. static void ConfigureHSI(void);
    9. static void InitializeMasterTxSPI(void);
    10. uint8_t s_TransferBuffer[10];

    12. int main()
    13. {        
    14.     s_TransferBuffer[0] = 0xAA;
    15.     s_TransferBuffer[1] = 0xBB;
    16.     s_TransferBuffer[2] = 0xCC;

    18.     ConfigureHSI();
    19.     InitializeMCO();
    20.     InitializeMasterTxSPI();
    21.     while(1){};
    22. }

    24. static void ConfigureHSI(void)
    25. {
    26.     PWR->CR3 |= PWR_CR3_SCUEN;
    27.     PWR->D3CR |= (PWR_D3CR_VOS_1 | PWR_D3CR_VOS_0);
    28.         while ((PWR->D3CR & PWR_D3CR_VOSRDY) != PWR_D3CR_VOSRDY)
    29.         {
    30.         };

    32.     FLASH->ACR = FLASH_ACR_LATENCY_2WS;

    34.     RCC->CR |= RCC_CR_HSION;
    35.     while ((RCC->CR & RCC_CR_HSIRDY) != RCC_CR_HSIRDY)
    36.     {
    37.     };

    39.     RCC->PLLCKSELR = (4u << RCC_PLLCKSELR_DIVM1_Pos) |
    40.                          (32u << RCC_PLLCKSELR_DIVM2_Pos) |
    41.                          (32u << RCC_PLLCKSELR_DIVM3_Pos) |
    42.                          RCC_PLLCKSELR_PLLSRC_HSI
    43.                          ;

    45.     RCC->PLLCFGR   =  RCC_PLLCFGR_DIVR1EN |
    46.                       RCC_PLLCFGR_DIVQ1EN |
    47.                       RCC_PLLCFGR_DIVP1EN |
    48.                       (2u << RCC_PLLCFGR_PLL1RGE_Pos)  |
    49.                       (1u << RCC_PLLCFGR_PLL1VCOSEL_Pos)
    50.                       ;

    52.     RCC->PLL1DIVR = ((2u - 1u) << RCC_PLL1DIVR_R1_Pos) |         
    53.         ((2u - 1u) << RCC_PLL1DIVR_Q1_Pos) |
    54.         ((2u - 1u) << RCC_PLL1DIVR_P1_Pos) |
    55.         ((10u - 1u) << RCC_PLL1DIVR_N1_Pos)  // Reducing the clock rate so I can probe it with my slow USB scope
    56.         ;

    58.     RCC->D1CFGR = RCC_D1CFGR_D1CPRE_DIV1;
    59.     RCC->D1CFGR = RCC_D1CFGR_HPRE_DIV2 |
    60.                   RCC_D1CFGR_D1PPRE_DIV2;
    61.     RCC->D2CFGR = RCC_D2CFGR_D2PPRE1_DIV2 |
    62.                   RCC_D2CFGR_D2PPRE2_DIV2;
    63.     RCC->D3CFGR = RCC_D3CFGR_D3PPRE_DIV2;

    65.     RCC->CR |= RCC_CR_PLL1ON;
    66.     while (!(RCC->CR & RCC_CR_PLLRDY))
    67.     {
    68.     };

    70.     RCC->CFGR |= (1u << 25);
    71.     RCC->CFGR |= RCC_CFGR_SW_PLL1;
    72.     while (!(RCC->CFGR & RCC_CFGR_SWS_PLL1))
    73.     {
    74.     };
    75. }

    77. /* Displays MCO on PC9 */
    78. static void InitializeMCO(void)
    79. {
    80.     RCC->CFGR |= RCC_CFGR_MCO2;
    81.         RCC->CFGR |= (15 << 25); // Reducing the output so I can probe it with my slow USB scope

    83.     RCC->AHB4ENR &= ~RCC_AHB4ENR_GPIOCEN;
    84.     RCC->AHB4ENR |= RCC_AHB4ENR_GPIOCEN;

    86.     GPIOC->MODER &= ~GPIO_MODER_MODER9;
    87.     GPIOC->MODER |= GPIO_MODER_MODER9_1;

    89.     GPIOC->OTYPER &= ~GPIO_OTYPER_OT_9;
    90.     GPIOC->PUPDR &= ~GPIO_PUPDR_PUPDR9;

    92.     GPIOC->OSPEEDR &= ~GPIO_OSPEEDER_OSPEEDR9;
    93.     GPIOC->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR9;

    95.     GPIOC->AFR[0] &= ~GPIO_AFRL_AFRL0;
    96. }

    98. static void InitializeMasterTxSPI(void)
    99. {
    100.     RCC->AHB4ENR |= RCC_AHB4ENR_GPIOAEN;   // Enable usage of GPIOA

    102.     GPIOA->MODER &= ~GPIO_MODER_MODER5;
    103.     GPIOA->MODER |= GPIO_MODER_MODER5_1;   // Alternate function for SPI1 SCK on PA5
    104.     GPIOA->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR5;   // High Speed on PA5
    105.     GPIOA->AFR[0] |= (0x05 << 5 * 4);   // AFRL selected AF5 (SPI1 SCK) for PA5

    107.     GPIOA->MODER &= ~GPIO_MODER_MODER6;
    108.     GPIOA->MODER |= GPIO_MODER_MODER6_1;   // Alternate function for SPI1 MISO on PA6
    109.     GPIOA->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR6;   // High Speed on PA6
    110.     GPIOA->AFR[0] |= (0x05 << 6 * 4);   // AFRL selected AF5 (SPI1 MISO) for PA6

    112.     GPIOA->MODER &= ~GPIO_MODER_MODER7;
    113.     GPIOA->MODER |= GPIO_MODER_MODER7_1;   // Alternate function for SPI1 MOSI on PA7
    114.     GPIOA->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR7;   // High Speed on PA7
    115.     GPIOA->AFR[0] |= (0x05 << 7 * 4);   // AFRL selected AF5 (SPI1 MOSI) for PA7

    117.     GPIOA->MODER &= ~GPIO_MODER_MODER4;
    118.     GPIOA->MODER |= GPIO_MODER_MODER4_1;   // Alternate function for SPI1 NSS on PA7
    119.     GPIOA->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR4;   // High Speed on PA7
    120.     GPIOA->AFR[0] |= (0x05 << 4 * 4);   // AFRL selected AF5 (SPI1 NSS) for PA7

    122.     GPIOA->PUPDR &= ~GPIO_PUPDR_PUPDR4;  // Ensure all pull up pull down resistors are enabled
    123.     GPIOA->PUPDR &= ~GPIO_PUPDR_PUPDR5;   // Ensure all pull up pull down resistors are disabled
    124.     GPIOA->PUPDR &= ~GPIO_PUPDR_PUPDR6;   // Ensure all pull up pull down resistors are disabled
    125.     GPIOA->PUPDR &= ~GPIO_PUPDR_PUPDR7;   // Ensure all pull up pull down resistors are disabled

    127.     RCC->APB2ENR |= RCC_APB2ENR_SPI1EN;

    129.     SPI1->CR1 = 0;

    131.     SPI1->CFG1 = (3u << SPI_CFG1_MBR_Pos) |
    132.                  (7u << SPI_CFG1_CRCSIZE_Pos) |
    133.                  //SPI_CFG1_TXDMAEN | // SPI_CFG1_RXDMAEN |
    134.                  (7u << SPI_CFG1_FTHLV_Pos) |
    135.                  (7u << SPI_CFG1_DSIZE_Pos)
    136.                  ;

    138.     SPI1->CFG2 = SPI_CFG2_SSOE |
    139.                  SPI_CFG2_MASTER
    140.                  ;      

    142.     SPI1->CR2 |= 3;
    143.     SPI1->CR1 |= SPI_CR1_SPE;
    144.     SPI1->CR1 |= SPI_CR1_CSTART;

    146.     for (uint32_t i=0; i<3; i++)
    147.     {
    148.             while ((SPI1->SR & SPI_SR_TXP) != SPI_SR_TXP){};
    149.             *((__IO uint32_t *)&SPI1->TXDR) = *((uint32_t *)&s_TransferBuffer[i]);
    150.     }
    151. }</font>
    复制代码    上面的代码基本上做了三件事：
    • ConfigureHSI 初始化HSI时钟（我已经降低了时钟速度，以便能够使用我目前拥有的慢速USB示波器进行一些探测）。
    • InitializeMCO 显示主时钟输出（只是为了确保时钟配置正确）。
    • InitializeMasterTxSPI 配置SPI并发出三字节消息。

    我绝对可以看到在我的示波器上发送的消息： 2.png 时基为200 ns / div，供参考。
    另一方面，如果我尝试通过DMA重做整个事情，我看不到任何输出。这就是我的基于DMA的SPI代码：
    1. <font size="4">#include "stm32h7xx.h"
    2. #include <stdio.h>
    3. #include <stdlib.h>
    4. #include <string.h>

    6. static void InitializeMCO(void);
    7. static void ConfigureHSI(void);
    8. static void InitializeDMA(void);
    9. static void InitializeMasterTxSPI(void);
    10. uint8_t s_TransferBuffer[10];

    12. int main()
    13. {        
    14.     s_TransferBuffer[0] = 0xAA;
    15.     s_TransferBuffer[1] = 0xBB;
    16.     s_TransferBuffer[2] = 0xCC;

    18.     ConfigureHSI();
    19.     InitializeMCO();
    20.     InitializeDMA();
    21.     InitializeMasterTxSPI();
    22.     while(1){};
    23. }

    25. /* Initializes the MCU clock */
    26. static void ConfigureHSI(void)
    27. {
    28.     PWR->CR3 |= PWR_CR3_SCUEN;
    29.     PWR->D3CR |= (PWR_D3CR_VOS_1 | PWR_D3CR_VOS_0);
    30.         while ((PWR->D3CR & PWR_D3CR_VOSRDY) != PWR_D3CR_VOSRDY)
    31.         {
    32.         };

    34.     FLASH->ACR = FLASH_ACR_LATENCY_2WS;

    36.     RCC->CR |= RCC_CR_HSION;
    37.     while ((RCC->CR & RCC_CR_HSIRDY) != RCC_CR_HSIRDY)
    38.     {
    39.     };

    41.     RCC->PLLCKSELR = (4u << RCC_PLLCKSELR_DIVM1_Pos) |
    42.                          (32u << RCC_PLLCKSELR_DIVM2_Pos) |
    43.                          (32u << RCC_PLLCKSELR_DIVM3_Pos) |
    44.                          RCC_PLLCKSELR_PLLSRC_HSI
    45.                          ;

    47.     RCC->PLLCFGR   =  RCC_PLLCFGR_DIVR1EN |
    48.                       RCC_PLLCFGR_DIVQ1EN |
    49.                       RCC_PLLCFGR_DIVP1EN |
    50.                       (2u << RCC_PLLCFGR_PLL1RGE_Pos)  |
    51.                       (1u << RCC_PLLCFGR_PLL1VCOSEL_Pos)
    52.                       ;

    54.     RCC->PLL1DIVR = ((2u - 1u) << RCC_PLL1DIVR_R1_Pos) |         
    55.         ((2u - 1u) << RCC_PLL1DIVR_Q1_Pos) |
    56.         ((2u - 1u) << RCC_PLL1DIVR_P1_Pos) |
    57.         ((10u - 1u) << RCC_PLL1DIVR_N1_Pos)  // Reducing the clock rate so I can probe it with my slow USB scope
    58.         ;

    60.     RCC->D1CFGR = RCC_D1CFGR_D1CPRE_DIV1;
    61.     RCC->D1CFGR = RCC_D1CFGR_HPRE_DIV2 |
    62.                   RCC_D1CFGR_D1PPRE_DIV2;
    63.     RCC->D2CFGR = RCC_D2CFGR_D2PPRE1_DIV2 |
    64.                   RCC_D2CFGR_D2PPRE2_DIV2;
    65.     RCC->D3CFGR = RCC_D3CFGR_D3PPRE_DIV2;

    67.     RCC->CR |= RCC_CR_PLL1ON;
    68.     while (!(RCC->CR & RCC_CR_PLLRDY))
    69.     {
    70.     };

    72.     RCC->CFGR |= (1u << 25);
    73.     RCC->CFGR |= RCC_CFGR_SW_PLL1;
    74.     while (!(RCC->CFGR & RCC_CFGR_SWS_PLL1))
    75.     {
    76.     };
    77. }

    79. /* Displays MCO on PC9 */
    80. static void InitializeMCO(void)
    81. {
    82.     RCC->CFGR |= RCC_CFGR_MCO2;
    83.     RCC->CFGR |= (15 << 25); // Reducing the output so I can probe it with my slow USB scope

    85.     RCC->AHB4ENR &= ~RCC_AHB4ENR_GPIOCEN;
    86.     RCC->AHB4ENR |= RCC_AHB4ENR_GPIOCEN;

    88.     GPIOC->MODER &= ~GPIO_MODER_MODER9;
    89.     GPIOC->MODER |= GPIO_MODER_MODER9_1;

    91.     GPIOC->OTYPER &= ~GPIO_OTYPER_OT_9;
    92.     GPIOC->PUPDR &= ~GPIO_PUPDR_PUPDR9;

    94.     GPIOC->OSPEEDR &= ~GPIO_OSPEEDER_OSPEEDR9;
    95.     GPIOC->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR9;

    97.     GPIOC->AFR[0] &= ~GPIO_AFRL_AFRL0;
    98. }

    100. static void InitializeDMA()
    101. {
    102.     RCC->AHB2ENR |= (0x7 << 29);  // Enable the SRAM
    103.     RCC->AHB1ENR |= RCC_AHB1ENR_DMA1EN;   // DMA1 clock enable;

    105.     // Set the peripheral and memory addresses:
    106.     DMA1_Stream0->PAR = *((__IO uint32_t *)&SPI1->TXDR);
    107.     DMA1_Stream0->M0AR = *((uint32_t *)&s_TransferBuffer[0]);

    109.     DMA1_Stream0->CR = 0u;
    110.     DMA1_Stream0->CR |= (1u << DMA_SxCR_DIR_Pos); // Memory to peripheral
    111.     DMA1_Stream0->CR |= DMA_SxCR_MINC; // Memory increment mode
    112.     DMA1_Stream0->CR |= (3u << DMA_SxCR_PL_Pos); // Very high priority

    114.     DMA1_Stream0->NDTR = 3; // Number of data

    116.     DMAMUX1_Channel0->CCR  = (38u << DMAMUX_CxCR_DMAREQ_ID_Pos);

    118. }

    120. static void InitializeMasterTxSPI(void)
    121. {
    122.     RCC->AHB4ENR |= RCC_AHB4ENR_GPIOAEN;   // Enable usage of GPIOA

    124.     GPIOA->MODER &= ~GPIO_MODER_MODER5;
    125.     GPIOA->MODER |= GPIO_MODER_MODER5_1;   // Alternate function for SPI1 SCK on PA5
    126.     GPIOA->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR5;   // High Speed on PA5
    127.     GPIOA->AFR[0] |= (0x05 << 5 * 4);   // AFRL selected AF5 (SPI1 SCK) for PA5

    129.     GPIOA->MODER &= ~GPIO_MODER_MODER6;
    130.     GPIOA->MODER |= GPIO_MODER_MODER6_1;   // Alternate function for SPI1 MISO on PA6
    131.     GPIOA->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR6;   // High Speed on PA6
    132.     GPIOA->AFR[0] |= (0x05 << 6 * 4);   // AFRL selected AF5 (SPI1 MISO) for PA6

    134.     GPIOA->MODER &= ~GPIO_MODER_MODER7;
    135.     GPIOA->MODER |= GPIO_MODER_MODER7_1;   // Alternate function for SPI1 MOSI on PA7
    136.     GPIOA->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR7;   // High Speed on PA7
    137.     GPIOA->AFR[0] |= (0x05 << 7 * 4);   // AFRL selected AF5 (SPI1 MOSI) for PA7

    139.     GPIOA->MODER &= ~GPIO_MODER_MODER4;
    140.     GPIOA->MODER |= GPIO_MODER_MODER4_1;   // Alternate function for SPI1 NSS on PA4
    141.     GPIOA->OSPEEDR |= GPIO_OSPEEDER_OSPEEDR4;   // High Speed on PA4
    142.     GPIOA->AFR[0] |= (0x05 << 4 * 4);   // AFRL selected AF5 (SPI1 NSS) for PA4

    144.     GPIOA->PUPDR &= ~GPIO_PUPDR_PUPDR4;  // Ensure all pull up pull down resistors are enabled
    145.     GPIOA->PUPDR &= ~GPIO_PUPDR_PUPDR5;   // Ensure all pull up pull down resistors are disabled
    146.     GPIOA->PUPDR &= ~GPIO_PUPDR_PUPDR6;   // Ensure all pull up pull down resistors are disabled
    147.     GPIOA->PUPDR &= ~GPIO_PUPDR_PUPDR7;   // Ensure all pull up pull down resistors are disabled

    149.     RCC->APB2ENR |= RCC_APB2ENR_SPI1EN;

    151.     SPI1->CR1 = 0;
    152.     SPI1->CFG1 = (3u << SPI_CFG1_MBR_Pos) |
    153.                  (7u << SPI_CFG1_CRCSIZE_Pos) |
    154.                  SPI_CFG1_TXDMAEN | // SPI_CFG1_RXDMAEN |
    155.                  (7u << SPI_CFG1_FTHLV_Pos) |
    156.                  (7u << SPI_CFG1_DSIZE_Pos)
    157.                  ;
    158.     SPI1->CFG2 = SPI_CFG2_SSOE |
    159.                  SPI_CFG2_MASTER
    160.                  ;      

    162.     //SPI1->CR2 |= 3;
    163.     SPI1->CR1 |= SPI_CR1_SPE;
    164.     SPI1->CR1 |= SPI_CR1_CSTART;

    166.     DMA1_Stream0->CR |= DMA_SxCR_EN;
    167. }</font>
    复制代码本质上，它是一回事，唯一的区别是有一个InitializeDMA功能，DMA传输是通过DMA1_Stream0->CR |= DMA_SxCR_EN命令启动的（就像之前的MCU系列中的情况一样）。所以，遗憾的是，我仍然无法通过H7上的DMA启动SPI。任何帮助将不胜感激。
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sjjs001
2019-07-15 05:42
 精彩回答 2  元偷偷看……0人看过

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