STM32之FSMC爬坑

FSMC之DM9000初始化问题，大多数开发板例程初始化都是这样的，包括官方的例程：

  FSMC_NORSRAMInitTypeDef  FSMC_NORSRAMInitStructure;
  FSMC_NORSRAMTimingInitTypeDef  p;
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_FSMC,ENABLE); //使能时钟
  p.FSMC_AddressSetupTime = 0;
  p.FSMC_AddressHoldTime = 0;
  p.FSMC_DataSetupTime = 1;
  p.FSMC_BusTurnAroundDuration = 0;
  p.FSMC_CLKDivision = 0;
  p.FSMC_DataLatency = 0;
  p.FSMC_AccessMode = FSMC_AccessMode_A;

  FSMC_NORSRAMInitStructure.FSMC_Bank = FSMC_Bank1_NORSRAM3;
  FSMC_NORSRAMInitStructure.FSMC_DataAddressMux = FSMC_DataAddressMux_Disable;
  FSMC_NORSRAMInitStructure.FSMC_MemoryType = FSMC_MemoryType_SRAM;
  FSMC_NORSRAMInitStructure.FSMC_MemoryDataWidth = FSMC_MemoryDataWidth_16b;
  FSMC_NORSRAMInitStructure.FSMC_BurstAccessMode = FSMC_BurstAccessMode_Disable;
  FSMC_NORSRAMInitStructure.FSMC_AsynchronousWait = FSMC_AsynchronousWait_Disable;  
  FSMC_NORSRAMInitStructure.FSMC_WaitSignalPolarity = FSMC_WaitSignalPolarity_Low;
  FSMC_NORSRAMInitStructure.FSMC_WrapMode = FSMC_WrapMode_Disable;
  FSMC_NORSRAMInitStructure.FSMC_WaitSignalActive =         
  FSMC_WaitSignalActive_BeforeWaitState;
  FSMC_NORSRAMInitStructure.FSMC_WriteOperation = FSMC_WriteOperation_Enable;
  FSMC_NORSRAMInitStructure.FSMC_WaitSignal = FSMC_WaitSignal_Disable;
  FSMC_NORSRAMInitStructure.FSMC_ExtendedMode = FSMC_ExtendedMode_Disable;
  FSMC_NORSRAMInitStructure.FSMC_WriteBurst = FSMC_WriteBurst_Disable;
  FSMC_NORSRAMInitStructure.FSMC_ReadWriteTimingStruct = &p;
  FSMC_NORSRAMInitStructure.FSMC_WriteTimingStruct = &p;   
 
  FSMC_NORSRAMInit(&FSMC_NORSRAMInitStructure); 
  /*!< Enable FSMC Bank1_SRAM Bank */
  FSMC_NORSRAMCmd(FSMC_Bank1_NORSRAM3, ENABLE); 

该程序在开发板例程下运行时没有问题的，自己移植过程中发现不能运行，一旦运行读写时，就会出现 HardFault_Handler 错误！

再上述代码中添加，    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_FSMC,ENABLE);    //使能 FSMC时钟
  FSMC_NORSRAMInitStructure.FSMC_ReadWriteTimingStruct = &p;
  FSMC_NORSRAMInitStructure.FSMC_WriteTimingStruct = &p;
  FSMC_NORSRAMStructInit(&FSMC_NORSRAMInitStructure);//给结构体赋初值

使用STM32库函数编程时最好给外设结构体 赋初值，比如 GPIO_StructInit(GPIO_InitTypeDef* GPIO_InitStruct)，如果不给 GPIO_InitStruct结构体赋初始值，那么它的初值时编译器赋的值，可能为 0！！！