只要stm32f4xx_fsmc.c这个在 就有以下错误，删除就没有了，想问问什么原因啊，这个fsmc有什么作用啊？
..FWLIBsrcstm32f4xx_fsmc.c(137): error:  #20: identifier "FSMC_Bank1" is undefined
      FSMC_Bank1->BTCR[FSMC_Bank] = 0x000030DB;    
..FWLIBsrcstm32f4xx_fsmc.c(142): error:  #20: identifier "FSMC_Bank1" is undefined
      FSMC_Bank1->BTCR[FSMC_Bank] = 0x000030D2; 
..FWLIBsrcstm32f4xx_fsmc.c(144): error:  #20: identifier "FSMC_Bank1" is undefined
    FSMC_Bank1->BTCR[FSMC_Bank + 1] = 0x0FFFFFFF;
..FWLIBsrcstm32f4xx_fsmc.c(145): error:  #20: identifier "FSMC_Bank1E" is undefined
    FSMC_Bank1E->BWTR[FSMC_Bank] = 0x0FFFFFFF;  
..FWLIBsrcstm32f4xx_fsmc.c(181): error:  #20: identifier "FSMC_Bank1" is undefined
    FSMC_Bank1->BTCR[FSMC_NORSRAMInitStruct->FSMC_Bank] = 
..FWLIBsrcstm32f4xx_fsmc.c(218): error:  #20: identifier "FSMC_Bank1E" is undefined
      FSMC_Bank1E->BWTR[FSMC_NORSRAMInitStruct->FSMC_Bank] = 
..FWLIBsrcstm32f4xx_fsmc.c(228): error:  #20: identifier "FSMC_Bank1E" is undefined
      FSMC_Bank1E->BWTR[FSMC_NORSRAMInitStruct->FSMC_Bank] = 0x0FFFFFFF;
..FWLIBsrcstm32f4xx_fsmc.c(277): error:  #20: identifier "FSMC_Bank1" is undefined
      FSMC_Bank1->BTCR[FSMC_Bank] |= BCR_MBKEN_SET;
..FWLIBsrcstm32f4xx_fsmc.c(282): error:  #20: identifier "FSMC_Bank1" is undefined
      FSMC_Bank1->BTCR[FSMC_Bank] &= BCR_MBKEN_RESET;
..FWLIBsrcstm32f4xx_fsmc.c(350): error:  #20: identifier "FSMC_Bank2" is undefined
      FSMC_Bank2->CR2 = 0x00000018;
..FWLIBsrcstm32f4xx_fsmc.c(359): error:  #20: identifier "FSMC_Bank3" is undefined
      FSMC_Bank3->CR3 = 0x00000018;
..FWLIBsrcstm32f4xx_fsmc.c(418): error:  #20: identifier "FSMC_Bank2" is undefined
      FSMC_Bank2->CR2 = tmppcr;
..FWLIBsrcstm32f4xx_fsmc.c(425): error:  #20: identifier "FSMC_Bank3" is undefined
      FSMC_Bank3->CR3 = tmppcr;
..FWLIBsrcstm32f4xx_fsmc.c(477): error:  #20: identifier "FSMC_Bank2" is undefined
        FSMC_Bank2->CR2 |= PCR_PBKEN_SET;
..FWLIBsrcstm32f4xx_fsmc.c(481): error:  #20: identifier "FSMC_Bank3" is undefined
        FSMC_Bank3->CR3 |= PCR_PBKEN_SET;
..FWLIBsrcstm32f4xx_fsmc.c(489): error:  #20: identifier "FSMC_Bank2" is undefined
        FSMC_Bank2->CR2 &= PCR_PBKEN_RESET;
..FWLIBsrcstm32f4xx_fsmc.c(493): error:  #20: identifier "FSMC_Bank3" is undefined
        FSMC_Bank3->CR3 &= PCR_PBKEN_RESET;
..FWLIBsrcstm32f4xx_fsmc.c(517): error:  #20: identifier "FSMC_Bank2" is undefined
        FSMC_Bank2->CR2 |= PCR_ECCEN_SET;
..FWLIBsrcstm32f4xx_fsmc.c(521): error:  #20: identifier "FSMC_Bank3" is undefined
        FSMC_Bank3->CR3 |= PCR_ECCEN_SET;
..FWLIBsrcstm32f4xx_fsmc.c(529): error:  #20: identifier "FSMC_Bank2" is undefined
        FSMC_Bank2->PCR2 &= PCR_ECCEN_RESET;
..FWLIBsrcstm32f4xx_fsmc.c(533): error:  #20: identifier "FSMC_Bank3" is undefined
        FSMC_Bank3->PCR3 &= PCR_ECCEN_RESET;
..FWLIBsrcstm32f4xx_fsmc.c(553): error:  #20: identifier "FSMC_Bank2" is undefined
      eccval = FSMC_Bank2->ECCR2;
..FWLIBsrcstm32f4xx_fsmc.c(558): error:  #20: identifier "FSMC_Bank3" is undefined
      eccval = FSMC_Bank3->ECCR3;
..FWLIBsrcstm32f4xx_fsmc.c(613): error:  #20: identifier "FSMC_Bank4" is undefined
    FSMC_Bank4->PCR4 = 0x00000018; 
..FWLIBsrcstm32f4xx_fsmc.c(649): error:  #20: identifier "FSMC_Bank4" is undefined
    FSMC_Bank4->PCR4 = (uint32_t)FSMC_PCCARDInitStruct->FSMC_Waitfeature |
..FWLIBsrcstm32f4xx_fsmc.c(712): error:  #20: identifier "FSMC_Bank4" is undefined
      FSMC_Bank4->PCR4 |= PCR_PBKEN_SET;
..FWLIBsrcstm32f4xx_fsmc.c(717): error:  #20: identifier "FSMC_Bank4" is undefined
      FSMC_Bank4->PCR4 &= PCR_PBKEN_RESET;
..FWLIBsrcstm32f4xx_fsmc.c(763): error:  #20: identifier "FSMC_Bank2" is undefined
        FSMC_Bank2->SR2 |= FSMC_IT;
..FWLIBsrcstm32f4xx_fsmc.c(768): error:  #20: identifier "FSMC_Bank3" is undefined
        FSMC_Bank3->SR3 |= FSMC_IT;
..FWLIBsrcstm32f4xx_fsmc.c(773): error:  #20: identifier "FSMC_Bank4" is undefined
        FSMC_Bank4->SR4 |= FSMC_IT;    
..FWLIBsrcstm32f4xx_fsmc.c: 0 warnings, 30 errors