spi接口初始化

void SPI1_Init(void)

{

GPIO_InitTypeDef GPIO_InitStructure;

SPI_InitTypeDef SPI_InitStructure;

RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);//使能GPIOA時鐘

RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);//使能SPI1時鐘

//GPIOF9,F10初始化設(shè)置

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5|GPIO_Pin_6|GPIO_Pin_7;//PB3~5復(fù)用功能輸出

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;//復(fù)用功能

GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;//推挽輸出

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;//100MHz

GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;//上拉

GPIO_Init(GPIOA, &GPIO_InitStructure);//初始化

GPIO_PinAFConfig(GPIOA,GPIO_PinSource5,GPIO_AF_SPI1); //PB3復(fù)用為 SPI1

GPIO_PinAFConfig(GPIOA,GPIO_PinSource6,GPIO_AF_SPI1); //PB4復(fù)用為 SPI1

GPIO_PinAFConfig(GPIOA,GPIO_PinSource7,GPIO_AF_SPI1); //PB5復(fù)用為 SPI1

//這里只針對SPI口初始化

RCC_APB2PeriphResetCmd(RCC_APB2Periph_SPI1,ENABLE);//復(fù)位SPI1

RCC_APB2PeriphResetCmd(RCC_APB2Periph_SPI1,DISABLE);//停止復(fù)位SPI1

SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;  //設(shè)置SPI單向或者雙向的數(shù)據(jù)模式:SPI設(shè)置為雙線雙向全雙工

SPI_InitStructure.SPI_Mode = SPI_Mode_Master; //設(shè)置SPI工作模式:設(shè)置為主SPI

SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b; //設(shè)置SPI的數(shù)據(jù)大小:SPI發(fā)送接收8位幀結(jié)構(gòu)

SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low; //串行同步時鐘的空閑狀態(tài)為高電平

SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge; //串行同步時鐘的第二個跳變沿（上升或下降）數(shù)據(jù)被采樣

SPI_InitStructure.SPI_NSS = SPI_NSS_Soft; //NSS信號由硬件（NSS管腳）還是軟件（使用SSI位）管理:內(nèi)部NSS信號有SSI位控制

SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_8; //定義波特率預(yù)分頻的值:波特率預(yù)分頻值為256

SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB; //指定數(shù)據(jù)傳輸從MSB位還是LSB位開始:數(shù)據(jù)傳輸從MSB位開始

SPI_InitStructure.SPI_CRCPolynomial = 7; //CRC值計算的多項式

SPI_Init(SPI1, &SPI_InitStructure);  //根據(jù)SPI_InitStruct中指定的參數(shù)初始化外設(shè)SPIx寄存器

SPI_Cmd(SPI1, ENABLE); //使能SPI外設(shè)

//SPI1_ReadWriteByte(0xff);//啟動傳輸  

}

//SPI1速度設(shè)置函數(shù)

//SpeedSet:0~7

//SPI速度=fAPB2/2^(SpeedSet+1)

//fAPB2時鐘一般為84Mhz

void SPI1_SetSpeed(u8 SPI_BaudRatePrescaler)

{

assert_param(IS_SPI_BAUDRATE_PRESCALER(SPI_BaudRatePrescaler));

SPI1->CR1&=0XFFC7;

SPI1->CR1|=SPI_BaudRatePrescaler; //設(shè)置SPI1速度

SPI_Cmd(SPI1,ENABLE);

}

//SPI1 讀寫一個字節(jié)

//TxData:要寫入的字節(jié)

//返回值:讀取到的字節(jié)

u8 SPI1_ReadWriteByte(u8 TxData)

{

u8 retry = 0;

while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET)

{

retry++;

if(retry > 200) return 0;

}//等待發(fā)送區(qū)空

SPI_I2S_SendData(SPI1, TxData); //通過外設(shè)SPIx發(fā)送一個byte  數(shù)據(jù)

retry = 0;

while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET)

{

retry++;

if(retry > 200) return 0;

} //等待接收完一個byte

return SPI_I2S_ReceiveData(SPI1); //返回通過SPIx最近接收的數(shù)據(jù)

}

FRAM接口

#ifndef __FRAM_H

#define __FRAM_H

#ifdef __cplusplus

extern “C” {

#endif

#include “stm32f4xx.h”

#define CMD_WREN 0x06

#define CMD_WRDI 0x04

#define CMD_RDSR 0x05

#define CMD_WRSR 0x01

#define CMD_READ 0x03

#define CMD_WRITE 0x02

#define GPIO_CSN GPIOA

#define GPIO_Pin_CSN GPIO_Pin_4

#define GPIO_RCC_CSN RCC_AHB1Periph_GPIOA

#define Set_FRAM_CSN() GPIO_SetBits(GPIO_CSN,GPIO_Pin_CSN)

#define Clr_FRAM_CSN() GPIO_ResetBits(GPIO_CSN,GPIO_Pin_CSN)

void FRAM_Init(void);

void FRAM_Write(u16 writeaddr,u8 *fbuf,u16 n);

void FRAM_Read(u16 readaddr,u8 *fbuf,u16 n);

#ifdef __cplusplus

}

#endif

#endif

#include “fram.h”

#include “spi.h”

//初始化SPI FLASH的IO口

void FRAM_Init(void)

{

GPIO_InitTypeDef GPIO_InitStructure;

RCC_AHB1PeriphClockCmd(GPIO_RCC_CSN, ENABLE);//使能GPIOB時鐘

//GPIOA4

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_CSN;//PB14

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;//輸出

GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;//推挽輸出

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;//100MHz

GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;//上拉

GPIO_Init(GPIO_CSN, &GPIO_InitStructure);//初始化

Set_FRAM_CSN();

SPI1_Init();     //初始化SPI

Clr_FRAM_CSN();

SPI1_ReadWriteByte(0xff);//啟動傳輸

Set_FRAM_CSN(); //SPI FLASH不選中

}

void FRAM_Write_Enable(void)

{

u16 i;

Clr_FRAM_CSN();

SPI1_ReadWriteByte(CMD_WREN); //發(fā)送讀取命令

Set_FRAM_CSN();

i=10;

while(i–);

}

void FRAM_Write(u16 writeaddr,u8 *fbuf,u16 n)

{

u16 i;

FRAM_Write_Enable(); //操作命令之前必須寫使能

Clr_FRAM_CSN(); //使能器件

SPI1_ReadWriteByte(CMD_WRITE); //發(fā)送讀取命令

SPI1_ReadWriteByte((u8)((writeaddr)>>8)); //發(fā)送16bit地址

SPI1_ReadWriteByte((u8)writeaddr);

for(i=0;i{

SPI1_ReadWriteByte(fbuf[i]); //循環(huán)讀數(shù)

}

Set_FRAM_CSN();

}

void FRAM_Read(u16 readaddr,u8 *fbuf,u16 n)

{

u16 i;

FRAM_Write_Enable(); //操作命令之前必須寫使能

Clr_FRAM_CSN(); //使能器件

SPI1_ReadWriteByte(CMD_READ); //發(fā)送讀取命令

SPI1_ReadWriteByte((u8)((readaddr)>>8)); //發(fā)送16bit地址

SPI1_ReadWriteByte((u8)readaddr);

for(i=0;i{

fbuf[i]=SPI1_ReadWriteByte(0xff); //循環(huán)讀數(shù)

}

Set_FRAM_CSN();

}

總結(jié)

1、操作讀寫之前要發(fā)送寫使能命令才進行操作

2、FRAM可以按字節(jié)操作或連接操作。