STM32H750 QSPI 映射不对问题请教

我使用STM32H750 QSPI W25Q64 作为外部FLASH，使用非映射方式读写FLASH 正常，映射后，读0X90000000地址的数据也正常，但是读0X90010000 地址的数据读到的是0XFF，但是 用W25Qx_QSPI_FastRead 读 0X10000确是正常的，请问哪位大侠知道是怎么回事情

if(W25Qx_QSPI_Init()!=QSPI_OK) { while(1); }

// W25Qx_QSPI_Read(ucD,0x0,8); W25Qx_QSPI_FastRead(&ucD[20],0x0000,8); W25Qx_QSPI_FastRead(&ucD[30],0x10000,8); // W25Qx_QSPI_Erase_Block(0); // W25Qx_QSPI_Write(ucDat,0x0,8); // W25Qx_QSPI_Read(ucD,0x0,8); W25Qx_QSPI_FastRead(&ucD[38],0x10008,8);

if(QSPI_EnableMemoryMappedMode(&hqspi)!= QSPI_OK) { while(1); }

 ucD[0] = *(unsigned char*)(0x8000000UL);

ucD[11] = (unsigned char)(0x90000000UL); ucD[12] = (unsigned char)(0x90000001UL); ucD[13] = (unsigned char)(0x90000002UL); ucD[14] = (unsigned char)(0x90000003UL);

ucD[1] = (unsigned char)(0x90010000UL); ucD[2] = (unsigned char)(0x90010001UL); ucD[3] = (unsigned char)(0x90010002UL); ucD[4] = (unsigned char)(0x90010003UL);