STM32的FSMC在读数据的时候一次能读几位？

只看该作者 · 2009-5-12 14:14

硬件上是接的8位的NAND FLASH  NAND128

下面是一段读ID的程序

/******************************************************************************
* Function Name  : FSMC_NAND_ReadID
* Description    : Reads NAND memory's ID.
* Input          : - NAND_ID: pointer to a NAND_IDTypeDef structure which will hold
*                    the Manufacturer and Device ID.
* Output         : None
* Return         : None
*******************************************************************************/
void FSMC_NAND_ReadID(NAND_IDTypeDef* NAND_ID)
{
  u32 data = 0;

  /* Send Command to the command area */
  *(vu8 *)(Bank_NAND_ADDR | CMD_AREA) = 0x90;    //写读ID命令
  *(vu8 *)(Bank_NAND_ADDR | ADDR_AREA) = 0x00;

   /* Sequence to read ID from NAND flash */
   data = *(vu32 *)(Bank_NAND_ADDR | DATA_AREA);   //读ID

   NAND_ID->Maker_ID   = data & 0xFF;
   NAND_ID->Device_ID  = (data & 0xFF00)>>8;
   NAND_ID->Third_ID   = (data & 0xFF0000)>>16;
   NAND_ID->Fourth_ID  = (data & 0xFF000000)>>24;
}

/* Sequence to read ID from NAND flash */
   data = *(vu32 *)(Bank_NAND_ADDR | DATA_AREA);

//这句就看不懂了，为什么能一次读32位

只看该作者 · 2009-5-12 14:16

#define Bank_NAND_ADDR    ((u32)0x70000000)

#define CMD_AREA                   (u32)(1<<16)  /* A16 = CLE  high */
#define ADDR_AREA                  (u32)(1<<17)  /* A17 = ALE high */