fmc_spi读flah和spi读flash

FMC(SRAM)和SPI都可以用来读取Flash，但是它们的实现方式不同。FMC(SRAM)是通过CPU的总线来访问Flash，而SPI是通过SPI总线来访问Flash。下面是两种读取Flash的例子：

1. FMC(SRAM)读取Flash

#define SRAM_BANK_ADDR ((uint32_t)0x60000000)
#define FLASH_ADDR ((uint32_t)0x08000000)

uint32_t read_flash(uint32_t addr)
{
    uint32_t data = 0;
    data = *(volatile uint32_t *)(SRAM_BANK_ADDR + (addr - FLASH_ADDR));
    return data;
}

2. SPI读取Flash

#define FLASH_CS_LOW()  HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, GPIO_PIN_RESET)
#define FLASH_CS_HIGH() HAL_GPIO_WritePin(GPIOA, GPIO_PIN_4, GPIO_PIN_SET)

void spi_read_flash(uint32_t addr, uint8_t *data, uint32_t size)
{
    FLASH_CS_LOW();
    SPI_FLASH_SendByte(Read_data);
    SPI_FLASH_SendByte((addr >> 16) & 0xff);
    SPI_FLASH_SendByte((addr >> 8) & 0xff);
    SPI_FLASH_SendByte(addr & 0xff);
    while (size--)
    {
        *data = SPI_FLASH_SendByte(Dummy_Byte);
        data++;
    }
    FLASH_CS_HIGH();
}