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rt-thread 如何使用多块sram

发布于 2025-02-26 17:48:10 浏览：145 订阅该版

芯片:STM32F407芯片

rtt版本:5.1.0

STM32F407 有两块内存

0x20000000 开始128K

0x10000000 开始64K

首先 配置内存管理,方式使用Use memheap objects as heap

![screenshot_a2b4d1ea2dcc0ef6322c3b221a0bccf4_2136486-20250120150213366-1142870473.png](https://oss-club.rt-thread.org/uploads/20250226/a24ab55b6c5254b12761eda1bb0fd5fd.png)
然后在board.h中增加RAM2的定义如下

```c
/*-------------------------- ROM/RAM CONFIG BEGIN --------------------------*/

#define ROM_START              ((uint32_t)0x08000000)
#define ROM_SIZE               (1024 * 1024)
#define ROM_END                ((uint32_t)(ROM_START + ROM_SIZE))

#define RAM_START              (0x20000000)
#define RAM_SIZE               (128 * 1024)
#define RAM_END                (RAM_START + RAM_SIZE)

#define RAM2_START              (0x10000000)
#define RAM2_SIZE               (64 * 1024)
#define RAM2_END                (RAM2_START + RAM2_SIZE)
```
在board.c中void rt_hw_board_init()中调用初始化sram2的函数

```c
int system_sram2_init(void)
{
    static struct rt_memheap memheap_sram2;
    /* Heap initialization */
#if defined(RT_USING_HEAP)
    rt_memheap_init(&memheap_sram2, "sram2", (void *)RAM2_START, (rt_size_t)RAM2_SIZE);
#endif
    return 0;
}

rt_weak void rt_hw_board_init()
{
    extern void hw_board_init(char *clock_src, int32_t clock_src_freq, int32_t clock_target_freq);

/* Heap initialization */
#if defined(RT_USING_HEAP)
    rt_system_heap_init((void *) HEAP_BEGIN, (void *) HEAP_END);
    system_sram2_init();
#endif

hw_board_init(BSP_CLOCK_SOURCE, BSP_CLOCK_SOURCE_FREQ_MHZ, BSP_CLOCK_SYSTEM_FREQ_MHZ);

/* Set the shell console output device */
#if defined(RT_USING_DEVICE) && defined(RT_USING_CONSOLE)
    rt_console_set_device(RT_CONSOLE_DEVICE_NAME);
#endif

/* Board underlying hardware initialization */
#ifdef RT_USING_COMPONENTS_INIT
    rt_components_board_init();
#endif

}
```

![screenshot_9c3054566503319f783225b938c80402_2136486-20250120145426772-2129839285.png](https://oss-club.rt-thread.org/uploads/20250226/6928a76f3f147a05974cbd1eeb92ab75.png.webp)

再增加一个片外sram内存
在board.h中增加 #define BSP_USING_SRAM
board.c中增加fsmc的初始化

```c
static void HAL_FSMC_MspInit(void){
  /* USER CODE BEGIN FSMC_MspInit 0 */

/* USER CODE END FSMC_MspInit 0 */
  GPIO_InitTypeDef GPIO_InitStruct = {0};
  if (FSMC_Initialized) {
    return;
  }
  FSMC_Initialized = 1;

/* Peripheral clock enable */
  __HAL_RCC_FSMC_CLK_ENABLE();

/** FSMC GPIO Configuration
  PF0   ------> FSMC_A0
  PF1   ------> FSMC_A1
  PF2   ------> FSMC_A2
  PF3   ------> FSMC_A3
  PF4   ------> FSMC_A4
  PF5   ------> FSMC_A5
  PF12   ------> FSMC_A6
  PF13   ------> FSMC_A7
  PF14   ------> FSMC_A8
  PF15   ------> FSMC_A9
  PG0   ------> FSMC_A10
  PG1   ------> FSMC_A11
  PE7   ------> FSMC_D4
  PE8   ------> FSMC_D5
  PE9   ------> FSMC_D6
  PE10   ------> FSMC_D7
  PE11   ------> FSMC_D8
  PE12   ------> FSMC_D9
  PE13   ------> FSMC_D10
  PE14   ------> FSMC_D11
  PE15   ------> FSMC_D12
  PD8   ------> FSMC_D13
  PD9   ------> FSMC_D14
  PD10   ------> FSMC_D15
  PD11   ------> FSMC_A16
  PD12   ------> FSMC_A17
  PD13   ------> FSMC_A18
  PD14   ------> FSMC_D0
  PD15   ------> FSMC_D1
  PG2   ------> FSMC_A12
  PG3   ------> FSMC_A13
  PG4   ------> FSMC_A14
  PG5   ------> FSMC_A15
  PD0   ------> FSMC_D2
  PD1   ------> FSMC_D3
  PD4   ------> FSMC_NOE
  PD5   ------> FSMC_NWE
  PG10   ------> FSMC_NE3
  PE0   ------> FSMC_NBL0
  PE1   ------> FSMC_NBL1
  */
  /* GPIO_InitStruct */
  GPIO_InitStruct.Pin = GPIO_PIN_0|GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3
                          |GPIO_PIN_4|GPIO_PIN_5|GPIO_PIN_12|GPIO_PIN_13
                          |GPIO_PIN_14|GPIO_PIN_15;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
  GPIO_InitStruct.Alternate = GPIO_AF12_FSMC;

HAL_GPIO_Init(GPIOF, &GPIO_InitStruct);

/* GPIO_InitStruct */
  GPIO_InitStruct.Pin = GPIO_PIN_0|GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3
                          |GPIO_PIN_4|GPIO_PIN_5|GPIO_PIN_10;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
  GPIO_InitStruct.Alternate = GPIO_AF12_FSMC;

HAL_GPIO_Init(GPIOG, &GPIO_InitStruct);

/* GPIO_InitStruct */
  GPIO_InitStruct.Pin = GPIO_PIN_7|GPIO_PIN_8|GPIO_PIN_9|GPIO_PIN_10
                          |GPIO_PIN_11|GPIO_PIN_12|GPIO_PIN_13|GPIO_PIN_14
                          |GPIO_PIN_15|GPIO_PIN_0|GPIO_PIN_1;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
  GPIO_InitStruct.Alternate = GPIO_AF12_FSMC;

HAL_GPIO_Init(GPIOE, &GPIO_InitStruct);

/* GPIO_InitStruct */
  GPIO_InitStruct.Pin = GPIO_PIN_8|GPIO_PIN_9|GPIO_PIN_10|GPIO_PIN_11
                          |GPIO_PIN_12|GPIO_PIN_13|GPIO_PIN_14|GPIO_PIN_15
                          |GPIO_PIN_0|GPIO_PIN_1|GPIO_PIN_4|GPIO_PIN_5;
  GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
  GPIO_InitStruct.Alternate = GPIO_AF12_FSMC;

HAL_GPIO_Init(GPIOD, &GPIO_InitStruct);

/* USER CODE BEGIN FSMC_MspInit 1 */

/* USER CODE END FSMC_MspInit 1 */
}
void HAL_SRAM_MspInit(SRAM_HandleTypeDef* sramHandle){
  /* USER CODE BEGIN SRAM_MspInit 0 */

/* USER CODE END SRAM_MspInit 0 */
  HAL_FSMC_MspInit();
  /* USER CODE BEGIN SRAM_MspInit 1 */

/* USER CODE END SRAM_MspInit 1 */
}
```
drv_sram.c中代码添加
rt_memheap_init(&system_heap, "sram", (void *)SRAM_BANK_ADDR, SRAM_SIZE);

```c
#ifdef RT_USING_MEMHEAP_AS_HEAP
static struct rt_memheap system_heap;
#endif

static SRAM_HandleTypeDef hsram;

static int rt_hw_sram_init(void)
{
    int result = RT_EOK;

FSMC_NORSRAM_TimingTypeDef Timing = {0};

/** Perform the SRAM2 memory initialization sequence
    */
    hsram.Instance = FSMC_NORSRAM_DEVICE;
    hsram.Extended = FSMC_NORSRAM_EXTENDED_DEVICE;
    /* hsram.Init */
    hsram.Init.NSBank = FSMC_NORSRAM_BANK3;
    hsram.Init.DataAddressMux = FSMC_DATA_ADDRESS_MUX_DISABLE;
    hsram.Init.MemoryType = FSMC_MEMORY_TYPE_SRAM;
#if SRAM_DATA_WIDTH == 8
    hsram.Init.MemoryDataWidth = FSMC_NORSRAM_MEM_BUS_WIDTH_8;
#elif SRAM_DATA_WIDTH == 16
    hsram.Init.MemoryDataWidth = FSMC_NORSRAM_MEM_BUS_WIDTH_16;
#else
    hsram.Init.MemoryDataWidth = FSMC_NORSRAM_MEM_BUS_WIDTH_32;
#endif
    hsram.Init.BurstAccessMode = FSMC_BURST_ACCESS_MODE_DISABLE;
    hsram.Init.WaitSignalPolarity = FSMC_WAIT_SIGNAL_POLARITY_LOW;
    hsram.Init.WrapMode = FSMC_WRAP_MODE_DISABLE;
    hsram.Init.WaitSignalActive = FSMC_WAIT_TIMING_BEFORE_WS;
    hsram.Init.WriteOperation = FSMC_WRITE_OPERATION_ENABLE;
    hsram.Init.WaitSignal = FSMC_WAIT_SIGNAL_DISABLE;
    hsram.Init.ExtendedMode = FSMC_EXTENDED_MODE_DISABLE;
    hsram.Init.AsynchronousWait = FSMC_ASYNCHRONOUS_WAIT_DISABLE;
    hsram.Init.WriteBurst = FSMC_WRITE_BURST_DISABLE;
    hsram.Init.PageSize = FSMC_PAGE_SIZE_NONE;

/* Timing */
    Timing.AddressSetupTime = 0;
    Timing.AddressHoldTime = 0;
    Timing.DataSetupTime = 8;
    Timing.BusTurnAroundDuration = 0;
    Timing.CLKDivision = 0;
    Timing.DataLatency = 0;
    Timing.AccessMode = FSMC_ACCESS_MODE_A;
    /* ExtTiming */

if (HAL_SRAM_Init(&hsram, &Timing, &Timing) != HAL_OK)
    {
        LOG_E("SRAM init failed!");
        result = -RT_ERROR;
    }
    else
    {
        LOG_D("sram init success, mapped at 0x%X, size is %d bytes, data width is %d", SRAM_BANK_ADDR, SRAM_SIZE, SRAM_DATA_WIDTH);
#ifdef RT_USING_MEMHEAP_AS_HEAP
        /* If RT_USING_MEMHEAP_AS_HEAP is enabled, SRAM is initialized to the heap */
        rt_memheap_init(&system_heap, "sram", (void *)SRAM_BANK_ADDR, SRAM_SIZE);
#endif
    }

```
free指令可以看到3块内存可以申请

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20250228/160362e08f02bfddd74193d7e27f79ca.png)