STM32F407 外扩SRAM
看看实现IS62WV51216的访问，需要对FSMC进行哪些配置。这里就做一个概括性的讲解。步骤如下：
本文引用地址：//m.amcfsurvey.com/article/201611/317497.htm1）使能FSMC时钟，并配置FSMC相关的IO及其时钟使能。
要使用FSMC，当然首先得开启其时钟。然后需要把FSMC_D0~15，FSMCA0~18等相关IO口，全部配置为复用输出，并使能各IO组的时钟。
使能FSMC时钟的方法：
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_FSMC,ENABLE);
对于其他IO口设置的方法前面讲解很详细，这里不做过多的讲解。
2）设置FSMCBANK1区域3。
此部分包括设置区域3的存储器的工作模式、位宽和读写时序等。我们使用模式A、16位宽，读写共用一个时序寄存器。使用的函数是：
void FSMC_NORSRAMInit(FSMC_NORSRAMInitTypeDef* FSMC_NORSRAMInitStruct)
3）使能BANK1区域3。
使能BANK的方法跟前面LCD实验一样，函数是：
void FSMC_NORSRAMCmd(uint32_t FSMC_Bank, FunctionalState NewState)；
通过以上几个步骤，完成了FSMC的配置，可以访问IS62WV51216了，这里还需要注意，因为我们使用的是BANK1的区域3，所以HADDR[27:26]=10，故外部内存的首地址为0X68000000。
代码：
#include "fsmc_sram.h"#define Bank1_SRAM3_ADDR ((u32)(0x68000000))void GPIO_SRAM_Init(void){GPIO_InitTypeDef GPIO_InitStructure;RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOE, ENABLE);RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOF, ENABLE);RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOG, ENABLE);GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_1|GPIO_Pin_2 |GPIO_Pin_3 |GPIO_Pin_14|GPIO_Pin_4|GPIO_Pin_5|GPIO_Pin_12|GPIO_Pin_13|GPIO_Pin_15;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;GPIO_Init(GPIOF, &GPIO_InitStructure);GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_1|GPIO_Pin_2 |GPIO_Pin_3 |GPIO_Pin_4|GPIO_Pin_5|GPIO_Pin_10;GPIO_Init(GPIOG, &GPIO_InitStructure);GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_1|GPIO_Pin_4 |GPIO_Pin_5 |GPIO_Pin_8|GPIO_Pin_9|GPIO_Pin_10|GPIO_Pin_11|GPIO_Pin_12|GPIO_Pin_13|GPIO_Pin_14|GPIO_Pin_15;GPIO_Init(GPIOD, &GPIO_InitStructure);GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_1|GPIO_Pin_7|GPIO_Pin_8|GPIO_Pin_9|GPIO_Pin_15|GPIO_Pin_10|GPIO_Pin_11|GPIO_Pin_12|GPIO_Pin_13|GPIO_Pin_14;GPIO_Init(GPIOE, &GPIO_InitStructure);GPIO_PinAFConfig(GPIOD, GPIO_PinSource0, GPIO_AF_FSMC);//D2GPIO_PinAFConfig(GPIOD, GPIO_PinSource1, GPIO_AF_FSMC);//D3GPIO_PinAFConfig(GPIOD, GPIO_PinSource4, GPIO_AF_FSMC);//NOEGPIO_PinAFConfig(GPIOD, GPIO_PinSource5, GPIO_AF_FSMC);//NWEGPIO_PinAFConfig(GPIOD, GPIO_PinSource8, GPIO_AF_FSMC);//D13GPIO_PinAFConfig(GPIOD, GPIO_PinSource9, GPIO_AF_FSMC);//D14GPIO_PinAFConfig(GPIOD, GPIO_PinSource10, GPIO_AF_FSMC);//D15GPIO_PinAFConfig(GPIOD, GPIO_PinSource11, GPIO_AF_FSMC);//A16GPIO_PinAFConfig(GPIOD, GPIO_PinSource12, GPIO_AF_FSMC);//A17GPIO_PinAFConfig(GPIOD, GPIO_PinSource13, GPIO_AF_FSMC);//A18GPIO_PinAFConfig(GPIOD, GPIO_PinSource14, GPIO_AF_FSMC);//D0GPIO_PinAFConfig(GPIOD, GPIO_PinSource15, GPIO_AF_FSMC);//D1GPIO_PinAFConfig(GPIOE, GPIO_PinSource0, GPIO_AF_FSMC);//NBL0GPIO_PinAFConfig(GPIOE, GPIO_PinSource1, GPIO_AF_FSMC);//NBL1GPIO_PinAFConfig(GPIOE, GPIO_PinSource7, GPIO_AF_FSMC);//D4GPIO_PinAFConfig(GPIOE, GPIO_PinSource8, GPIO_AF_FSMC);//D5GPIO_PinAFConfig(GPIOE, GPIO_PinSource9, GPIO_AF_FSMC);//D6GPIO_PinAFConfig(GPIOE, GPIO_PinSource10, GPIO_AF_FSMC);//D7GPIO_PinAFConfig(GPIOE, GPIO_PinSource11, GPIO_AF_FSMC);//D8GPIO_PinAFConfig(GPIOE, GPIO_PinSource12, GPIO_AF_FSMC);//D9GPIO_PinAFConfig(GPIOE, GPIO_PinSource13, GPIO_AF_FSMC);//D10GPIO_PinAFConfig(GPIOE, GPIO_PinSource14, GPIO_AF_FSMC);//D11GPIO_PinAFConfig(GPIOE, GPIO_PinSource15, GPIO_AF_FSMC);//D12GPIO_PinAFConfig(GPIOG, GPIO_PinSource0, GPIO_AF_FSMC);//A10GPIO_PinAFConfig(GPIOG, GPIO_PinSource1, GPIO_AF_FSMC);//A11GPIO_PinAFConfig(GPIOG, GPIO_PinSource2, GPIO_AF_FSMC);//A12GPIO_PinAFConfig(GPIOG, GPIO_PinSource3, GPIO_AF_FSMC);//A13GPIO_PinAFConfig(GPIOG, GPIO_PinSource4, GPIO_AF_FSMC);//A14GPIO_PinAFConfig(GPIOG, GPIO_PinSource5, GPIO_AF_FSMC);//A15GPIO_PinAFConfig(GPIOG, GPIO_PinSource10, GPIO_AF_FSMC);//NE3GPIO_PinAFConfig(GPIOF, GPIO_PinSource0, GPIO_AF_FSMC);//A0GPIO_PinAFConfig(GPIOF, GPIO_PinSource1, GPIO_AF_FSMC);//A1GPIO_PinAFConfig(GPIOF, GPIO_PinSource2, GPIO_AF_FSMC);//A2GPIO_PinAFConfig(GPIOF, GPIO_PinSource3, GPIO_AF_FSMC);//A3GPIO_PinAFConfig(GPIOF, GPIO_PinSource4, GPIO_AF_FSMC);//A4GPIO_PinAFConfig(GPIOF, GPIO_PinSource5, GPIO_AF_FSMC);//A5GPIO_PinAFConfig(GPIOF, GPIO_PinSource12, GPIO_AF_FSMC);//A6GPIO_PinAFConfig(GPIOF, GPIO_PinSource13, GPIO_AF_FSMC);//A7GPIO_PinAFConfig(GPIOF, GPIO_PinSource14, GPIO_AF_FSMC);//A8GPIO_PinAFConfig(GPIOF, GPIO_PinSource15, GPIO_AF_FSMC);//A9}void FSMC_SRAM_Init(void){ FSMC_NORSRAMInitTypeDef FSMC_NORSRAMInitStructure;FSMC_NORSRAMTimingInitTypeDef p;p.FSMC_AddressSetupTime = 0x00; //地址建立时间（ADDSET）为1个HCLK 1/36M=27nsp.FSMC_AddressHoldTime = 0x00; //地址保持时间（ADDHLD）模式A未用到 p.FSMC_DataSetupTime = 0x03; //数据保持时间（DATAST）为3个HCLK 4/72M=55ns(对EM的SRAM芯片) p.FSMC_BusTurnAroundDuration = 0x00;p.FSMC_CLKDivision = 0x00;p.FSMC_DataLatency = 0x00;p.FSMC_AccessMode = FSMC_AccessMode_A; //模式AFSMC_NORSRAMInitStructure.FSMC_Bank = FSMC_Bank1_NORSRAM3;// 这里我们使用NE3 ，也就对应BTCR[4],[5]。FSMC_NORSRAMInitStructure.FSMC_DataAddressMux = FSMC_DataAddressMux_Disable;FSMC_NORSRAMInitStructure.FSMC_MemoryType =FSMC_MemoryType_SRAM;// FSMC_MemoryType_SRAM; //SRAMFSMC_NORSRAMInitStructure.FSMC_MemoryDataWidth = FSMC_MemoryDataWidth_16b;//存储器数据宽度为16bitFSMC_NORSRAMInitStructure.FSMC_BurstAccessMode =FSMC_BurstAccessMode_Disable;// FSMC_BurstAccessMode_Disable;FSMC_NORSRAMInitStructure.FSMC_WaitSignalPolarity = FSMC_WaitSignalPolarity_Low;FSMC_NORSRAMInitStructure.FSMC_AsynchronousWait=FSMC_AsynchronousWait_Disable;FSMC_NORSRAMInitStructure.FSMC_WrapMode = FSMC_WrapMode_Disable;FSMC_NORSRAMInitStructure.FSMC_WaitSignalActive = FSMC_WaitSignalActive_BeforeWaitState;FSMC_NORSRAMInitStructure.FSMC_WriteOperation = FSMC_WriteOperation_Enable; //存储器写使能FSMC_NORSRAMInitStructure.FSMC_WaitSignal = FSMC_WaitSignal_Disable;FSMC_NORSRAMInitStructure.FSMC_ExtendedMode = FSMC_ExtendedMode_Disable; // 读写使用相同的时序FSMC_NORSRAMInitStructure.FSMC_WriteBurst = FSMC_WriteBurst_Disable;FSMC_NORSRAMInitStructure.FSMC_ReadWriteTimingStruct = &p;FSMC_NORSRAMInitStructure.FSMC_WriteTimingStruct = &p; //读写同样时序FSMC_NORSRAMInit(&FSMC_NORSRAMInitStructure); //初始化FSMC配置FSMC_NORSRAMCmd(FSMC_Bank1_NORSRAM3, ENABLE); // 使能BANK3 }void SRAM_Init(void){GPIO_SRAM_Init();FSMC_SRAM_Init();}/* -------------------------------在指定地址开始,连续写入n个字节.pBuffer:字节指针WriteAddr:要写入的地址n:要写入的字节数--------------------------------*/void FSMC_SRAM_WriteBuffer(u8* pBuffer,u32 WriteAddr,u32 n){for(;n!=0;n--){ *(vu8*)(Bank1_SRAM3_ADDR+WriteAddr)=*pBuffer; WriteAddr+=2;pBuffer++;}}/*-------------------------------在指定地址开始,连续读出n个字节.pBuffer:字节指针ReadAddr:要读出的起始地址n:要写入的字节数--------------------------------*/void FSMC_SRAM_ReadBuffer(u8* pBuffer,u32 ReadAddr,u32 n){for(;n!=0;n--){ *pBuffer++=*(vu8*)(Bank1_SRAM3_ADDR+ReadAddr);ReadAddr+=2;}}/*-------------------------------测试函数在指定地址写入1个字节addr:地址data:要写入的数据-------------------------------*/void fsmc_sram_test_write(u8 data,u32 addr){ FSMC_SRAM_WriteBuffer(&data,addr,1); //写入1个字节}/*------------------------------读取1个字节addr:要读取的地址返回值:读取到的数据------------------------------*/u8 fsmc_sram_test_read(u32 addr){u8 data;FSMC_SRAM_ReadBuffer(&data,addr,1);return data;}
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