HAL 库学习笔记：七、SDRAM 驱动之 MT48LC4M32B2B5-6A

1.如何使用此驱动程序

此驱动程序用于驱动已安装的 MT48LC4M32B2B5-6A SDRAM外部存储器的 STM32 控制电路系统。

2.驱动程序说明

• 初始化步骤：

  • 使用 BSP_SDRAM_Init（）函数初始化 SDRAM 外部存储器。这个功能包括 MSP 层硬件资源初始化和 FMC 控制器与外部 SDRAM 存储器接口的配置。
  • 它使用 BSP_SDRAM_Initialization_sequence（）对 SDRAM 芯片进行初始化配置。请注意，不同的 SDRAM 芯片的初始化程序可能有所不同。如果是这样，请根据具体芯片初始化步骤进行具体操作。

• SDRAM读/写操作：

  • SDRAM外部存储器可以通过读/写操作进行访问初始化。可以使用以下功能通过AHB访问执行读/写操作BSP_SDRAM_ReadData（）/BSP_SDRAM_WriteData（），或通过使用函数的DMA传输BSP_SDRAM_ReadData_DMA（）/BSP_SDRAM_WriteData_DMA（）。
  • 通过32位宽度的事务（DMA传输）执行AHB访问配置固定为单（无突发）字传输（请参阅 BSP_SDRAM_MspInit（）弱函数）。
  • 用户可以根据自己的需要实现自己的读写访问功能配置。
  • 如果将中断模式用于DMA传输，则函数BSP_SDRAM_DMA_IRQHandler（）在IRQ处理程序文件中被调用，以在DMA一旦产生后产生中断转移完成。
  • 您可以使用功能在运行时将命令发送到SDRAM设备BSP_SDRAM_Sendcmd（），并提供所需的命令作为在“ FMC_SDRAM_CommandTypeDef”结构的预定义命令。

3. 代码讲解

// 初始化
uint8_t BSP_SDRAM_Init(void);
// 去初始化
uint8_t BSP_SDRAM_DeInit(void);
// 序列初始化
void    BSP_SDRAM_Initialization_sequence(uint32_t RefreshCount);
// 读取数据
uint8_t BSP_SDRAM_ReadData(uint32_t uwStartAddress, uint32_t *pData, uint32_t uwDataSize);
uint8_t BSP_SDRAM_ReadData_DMA(uint32_t uwStartAddress, uint32_t *pData, uint32_t uwDataSize);
// 写数据
uint8_t BSP_SDRAM_WriteData(uint32_t uwStartAddress, uint32_t *pData, uint32_t uwDataSize);
uint8_t BSP_SDRAM_WriteData_DMA(uint32_t uwStartAddress, uint32_t *pData, uint32_t uwDataSize);
// 发送指令
uint8_t BSP_SDRAM_Sendcmd(FMC_SDRAM_CommandTypeDef *SdramCmd);
// 中断回调
void    BSP_SDRAM_DMA_IRQHandler(void);

3.1 私有变量

static SDRAM_HandleTypeDef sdramHandle;
static FMC_SDRAM_TimingTypeDef Timing;
static FMC_SDRAM_CommandTypeDef Command;

3.2 初始化

/**
  * @brief  Initializes the SDRAM device.
  * @retval SDRAM status
  */
uint8_t BSP_SDRAM_Init(void)
{
  static uint8_t sdramstatus = SDRAM_ERROR;

  /* SDRAM device configuration */
  sdramHandle.Instance = FMC_SDRAM_DEVICE;

  /* Timing configuration for 90 MHz as SD clock frequency (System clock is up to 180 MHz) */
  Timing.LoadToActiveDelay    = 2;
  Timing.ExitSelfRefreshDelay = 7;
  Timing.SelfRefreshTime      = 4;
  Timing.RowCycleDelay        = 7;
  Timing.WriteRecoveryTime    = 2;
  Timing.RPDelay              = 2;
  Timing.RCDDelay             = 2;

  sdramHandle.Init.SDBank             = FMC_SDRAM_BANK1;
  sdramHandle.Init.ColumnBitsNumber   = FMC_SDRAM_COLUMN_BITS_NUM_8;
  sdramHandle.Init.RowBitsNumber      = FMC_SDRAM_ROW_BITS_NUM_12;
  sdramHandle.Init.MemoryDataWidth    = SDRAM_MEMORY_WIDTH;
  sdramHandle.Init.InternalBankNumber = FMC_SDRAM_INTERN_BANKS_NUM_4;
  sdramHandle.Init.CASLatency         = FMC_SDRAM_CAS_LATENCY_3;
  sdramHandle.Init.WriteProtection    = FMC_SDRAM_WRITE_PROTECTION_DISABLE;
  sdramHandle.Init.SDClockPeriod      = SDCLOCK_PERIOD;
  sdramHandle.Init.ReadBurst          = FMC_SDRAM_RBURST_ENABLE;
  sdramHandle.Init.ReadPipeDelay      = FMC_SDRAM_RPIPE_DELAY_0;

  /* SDRAM controller initialization */
  /* __weak function can be surcharged by the application code */
  BSP_SDRAM_MspInit(&sdramHandle, (void *)NULL);
  if(HAL_SDRAM_Init(&sdramHandle, &Timing) != HAL_OK)
  {
    sdramstatus = SDRAM_ERROR;
  }
  else
  {
    sdramstatus = SDRAM_OK;
  }

  /* SDRAM initialization sequence */
  BSP_SDRAM_Initialization_sequence(REFRESH_COUNT);

  return sdramstatus;
}

3.3 SDRAM 编程配置

/**
  * @brief  Programs the SDRAM device.
  * @param  RefreshCount: SDRAM refresh counter value
  */
void BSP_SDRAM_Initialization_sequence(uint32_t RefreshCount)
{
  __IO uint32_t tmpmrd = 0;

  /* Step 1: Configure a clock configuration enable command */
  Command.CommandMode            = FMC_SDRAM_CMD_CLK_ENABLE;
  Command.CommandTarget          = FMC_SDRAM_CMD_TARGET_BANK1;
  Command.AutoRefreshNumber      = 1;
  Command.ModeRegisterDefinition = 0;

  /* Send the command */
  HAL_SDRAM_SendCommand(&sdramHandle, &Command, SDRAM_TIMEOUT);

  /* Step 2: Insert 100 us minimum delay */
  /* Inserted delay is equal to 1 ms due to systick time base unit (ms) */
  HAL_Delay(1);

  /* Step 3: Configure a PALL (precharge all) command */
  Command.CommandMode            = FMC_SDRAM_CMD_PALL;
  Command.CommandTarget          = FMC_SDRAM_CMD_TARGET_BANK1;
  Command.AutoRefreshNumber      = 1;
  Command.ModeRegisterDefinition = 0;

  /* Send the command */
  HAL_SDRAM_SendCommand(&sdramHandle, &Command, SDRAM_TIMEOUT);

  /* Step 4: Configure an Auto Refresh command */
  Command.CommandMode            = FMC_SDRAM_CMD_AUTOREFRESH_MODE;
  Command.CommandTarget          = FMC_SDRAM_CMD_TARGET_BANK1;
  Command.AutoRefreshNumber      = 8;
  Command.ModeRegisterDefinition = 0;

  /* Send the command */
  HAL_SDRAM_SendCommand(&sdramHandle, &Command, SDRAM_TIMEOUT);

  /* Step 5: Program the external memory mode register */
  tmpmrd = (uint32_t)SDRAM_MODEREG_BURST_LENGTH_1          |\
                     SDRAM_MODEREG_BURST_TYPE_SEQUENTIAL   |\
                     SDRAM_MODEREG_CAS_LATENCY_3           |\
                     SDRAM_MODEREG_OPERATING_MODE_STANDARD |\
                     SDRAM_MODEREG_WRITEBURST_MODE_SINGLE;

  Command.CommandMode            = FMC_SDRAM_CMD_LOAD_MODE;
  Command.CommandTarget          = FMC_SDRAM_CMD_TARGET_BANK1;
  Command.AutoRefreshNumber      = 1;
  Command.ModeRegisterDefinition = tmpmrd;

  /* Send the command */
  HAL_SDRAM_SendCommand(&sdramHandle, &Command, SDRAM_TIMEOUT);

  /* Step 6: Set the refresh rate counter */
  /* Set the device refresh rate */
  HAL_SDRAM_ProgramRefreshRate(&sdramHandle, RefreshCount);
}

3.4 读数据

/**
  * @brief  Reads an mount of data from the SDRAM memory in polling mode.
  * @param  uwStartAddress: Read start address
  * @param  pData: Pointer to data to be read
  * @param  uwDataSize: Size of read data from the memory
  * @retval SDRAM status : SDRAM_OK or SDRAM_ERROR.
  */
uint8_t BSP_SDRAM_ReadData(uint32_t uwStartAddress, uint32_t *pData, uint32_t uwDataSize)
{
  if(HAL_SDRAM_Read_32b(&sdramHandle, (uint32_t *)uwStartAddress, pData, uwDataSize) != HAL_OK)
  {
    return SDRAM_ERROR;
  }
  else
  {
    return SDRAM_OK;
  }
}

/**
  * @brief  Reads an mount of data from the SDRAM memory in DMA mode.
  * @param  uwStartAddress: Read start address
  * @param  pData: Pointer to data to be read
  * @param  uwDataSize: Size of read data from the memory
  * @retval SDRAM status : SDRAM_OK or SDRAM_ERROR.
  */
uint8_t BSP_SDRAM_ReadData_DMA(uint32_t uwStartAddress, uint32_t *pData, uint32_t uwDataSize)
{
  if(HAL_SDRAM_Read_DMA(&sdramHandle, (uint32_t *)uwStartAddress, pData, uwDataSize) != HAL_OK)
  {
    return SDRAM_ERROR;
  }
  else
  {
    return SDRAM_OK;
  }
}

3.5 写数据

/**
  * @brief  Writes an mount of data to the SDRAM memory in polling mode.
  * @param  uwStartAddress: Write start address
  * @param  pData: Pointer to data to be written
  * @param  uwDataSize: Size of written data from the memory
  * @retval SDRAM status : SDRAM_OK or SDRAM_ERROR.
  */
uint8_t BSP_SDRAM_WriteData(uint32_t uwStartAddress, uint32_t *pData, uint32_t uwDataSize)
{
  if(HAL_SDRAM_Write_32b(&sdramHandle, (uint32_t *)uwStartAddress, pData, uwDataSize) != HAL_OK)
  {
    return SDRAM_ERROR;
  }
  else
  {
    return SDRAM_OK;
  }
}

/**
  * @brief  Writes an mount of data to the SDRAM memory in DMA mode.
  * @param  uwStartAddress: Write start address
  * @param  pData: Pointer to data to be written
  * @param  uwDataSize: Size of written data from the memory
  * @retval SDRAM status : SDRAM_OK or SDRAM_ERROR.
  */
uint8_t BSP_SDRAM_WriteData_DMA(uint32_t uwStartAddress, uint32_t *pData, uint32_t uwDataSize)
{
  if(HAL_SDRAM_Write_DMA(&sdramHandle, (uint32_t *)uwStartAddress, pData, uwDataSize) != HAL_OK)
  {
    return SDRAM_ERROR;
  }
  else
  {
    return SDRAM_OK;
  }
}

3.6 写指令

/**
  * @brief  Sends command to the SDRAM bank.
  * @param  SdramCmd: Pointer to SDRAM command structure
  * @retval HAL status : SDRAM_OK or SDRAM_ERROR.
  */
uint8_t BSP_SDRAM_Sendcmd(FMC_SDRAM_CommandTypeDef *SdramCmd)
{
  if(HAL_SDRAM_SendCommand(&sdramHandle, SdramCmd, SDRAM_TIMEOUT) != HAL_OK)
  {
    return SDRAM_ERROR;
  }
  else
  {
    return SDRAM_OK;
  }
}