灵动微课堂 (第190讲) | 使用MM32F3270 FSMC驱动外部NOR Flash

2
FSMC非复用方式控制NOR Flash的程序设计
根据配置的接口电路配置GPIO初始化程序与FSMC初始化程序。void FSMC_NOR_Init(void)
{
    FSMC_InitTypeDef  FSMC_InitStructure;
    FSMC_NORSRAM_Bank_InitTypeDef  FSMC_BankInitStructure;

    FSMC_NORSRAM_BankStructinit(&FSMC_BankInitStructure);
    FSMC_NORSRAMStructInit(&FSMC_InitStructure);
    RCC_AHB3PeriphClockCmd(RCC_AHB3ENR_FSMC, ENABLE);

    FSMC_BankInitStructure.FSMC_SMReadPipe    = 0;
    FSMC_BankInitStructure.FSMC_ReadyMode     = 0;
    FSMC_BankInitStructure.FSMC_WritePeriod   = 15;
    FSMC_BankInitStructure.FSMC_WriteHoldTime = 3;
    FSMC_BankInitStructure.FSMC_AddrSetTime   = 3;
    FSMC_BankInitStructure.FSMC_ReadPeriod    = 15;
    FSMC_BankInitStructure.FSMC_DataWidth     = FSMC_DataWidth_16bits;
    FSMC_NORSRAM_Bank_Init(&FSMC_BankInitStructure,
    FSMC_NORSRAM_BANK1);

    FSMC_InitStructure.FSMC_Mode = FSMC_Mode_NorFlash;
    FSMC_InitStructure.FSMC_TimingRegSelect = FSMC_TimingRegSelect_0;
    FSMC_InitStructure.FSMC_MemSize = FSMC_MemSize_64MB;
    FSMC_InitStructure.FSMC_MemType = FSMC_MemType_FLASH;
    FSMC_InitStructure.FSMC_AddrDataMode = FSMC_AddrDataDeMUX;
    FSMC_NORSRAMInit(&FSMC_InitStructure);
}

GPIO初始化void FSMC_GPIO_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    GPIO_StructInit(&GPIO_InitStructure);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);
    RCC_AHBPeriphClockCmd(RCC_AHBENR_GPIOB | RCC_AHBENR_GPIOC |
    RCC_AHBENR_GPIOA | RCC_AHBENR_GPIOD | RCC_AHBENR_GPIOE |
    RCC_AHBENR_GPIOF | RCC_AHBENR_GPIOG, ENABLE);

    GPIO_PinAFConfig(GPIOD, GPIO_PinSource4, GPIO_AF_12);  //NOE
    GPIO_PinAFConfig(GPIOD, GPIO_PinSource5, GPIO_AF_12);  //NWE
    GPIO_PinAFConfig(GPIOD, GPIO_PinSource6, GPIO_AF_12);  //NWAIT
    GPIO_PinAFConfig(GPIOD, GPIO_PinSource11, GPIO_AF_12); //A16
    GPIO_PinAFConfig(GPIOD, GPIO_PinSource12, GPIO_AF_12); //A17
    GPIO_PinAFConfig(GPIOD, GPIO_PinSource13, GPIO_AF_12); //A18
    GPIO_PinAFConfig(GPIOD, GPIO_PinSource14, GPIO_AF_12); //D0
    GPIO_PinAFConfig(GPIOD, GPIO_PinSource15, GPIO_AF_12); //D1
    //省略部分代码
    GPIO_PinAFConfig(GPIOF, GPIO_PinSource0, GPIO_AF_12);  //A0
    GPIO_PinAFConfig(GPIOF, GPIO_PinSource1, GPIO_AF_12);  //A1
    GPIO_PinAFConfig(GPIOF, GPIO_PinSource2, GPIO_AF_12);  //A2
    GPIO_PinAFConfig(GPIOF, GPIO_PinSource3, GPIO_AF_12);  //A3
    //省略部分代码
    GPIO_InitStructure.GPIO_Pin  =  GPIO_Pin_All;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_Init(GPIOD, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin  =  GPIO_Pin_6;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_FLOATING;
    GPIO_Init(GPIOD, &GPIO_InitStructure);

    //省略部分代码

}

从选择的片选信号与FSMC外扩存储映像空间可以得出Bank2地址为0x64000000，使用该地址作为读写外部NOR Flash的基地址。#define NOR_FLASH_START_ADDR       ((u32)0x64000000)
#define NOR_FLASH_END_ADDR         ((u32)0x67FFFFFF)
//读一个半字
u16 FSMC_NOR_ReadHalfWord(u32 ReadAddr)
{
    NOR_WRITE(ADDR_SHIFT(0x00555), 0x00AA);
    NOR_WRITE(ADDR_SHIFT(0x002AA), 0x0055);
    NOR_WRITE((NOR_FLASH_START_ADDR + ReadAddr), 0x00F0 );
/* exit autoselect (write reset command) */
    return (*(vu16*)((NOR_FLASH_START_ADDR + ReadAddr)));
}
//连续读一块半字数据
void FSMC_NOR_ReadBuffer(u16* pBuffer, u32 ReadAddr, u32 NumHalfwordToRead)
{
    NOR_WRITE(ADDR_SHIFT(0x0555), 0x00AA);
    NOR_WRITE(ADDR_SHIFT(0x02AA), 0x0055);
    NOR_WRITE((NOR_FLASH_START_ADDR + ReadAddr), 0x00F0);
/* exit autoselect (write reset command) */
    for(; NumHalfwordToRead != 0x00; NumHalfwordToRead--) {
        // Read a Halfword from the NOR
        *pBuffer++ = *(vu16*)((NOR_FLASH_START_ADDR + ReadAddr));
        ReadAddr = ReadAddr + 2;
    }
}

读写外部NOR Flash与读写外部SRAM的操作，地址寻址方式是一样的，但NOR Flash的写数据有较大的不同。

以单个Word编程为例，如下为写单个Word的流程图与实现代码：