AVR單片機(jī)SPI的應(yīng)用（AT25256）

/**************************************硬件：單片機(jī)mega162，EEPROM 25256，晶振3.6864MHZ編譯環(huán)境：ICC****************************************/#includeiom162v.h>#define BAUD 9600   //波特率4800#define CRYSTAL 3686400  //晶振3M#define BAUD_set (unsigned int)( (unsigned long)CRYSTAL/

(16*(unsigned long)BAUD)-1 ) //波特率計算#define BAUD_H (unsigned char)(BAUD_set>>8) //波特率寄存器#define BAUD_L (unsigned char)(BAUD_set)/*//GPRS#define GPRS_ONOFFH  PORTA|=(1PA5)#define GPRS_ONOFFL  PORTA=~(1PA5)#define GPRS_RSTH    PORTB|=(1PB1)#define GPRS_RSTL    PORTB=~(1PB1)//通訊燈#define LED1H  PORTC|=(1PC4)#define LED1L  PORTC=~(1PC4)#define LED2H  PORTC|=(1PC6)#define LED2L  PORTC=~(1PC6)#define LED3H  PORTC|=(1PC7)#define LED3L  PORTC=~(1PC7)*///25256#define EEPROM_CSH  PORTD|=(1PD5)   //#define EEPROM_CSL  PORTD=~(1PD5) #define EEPROM_WPH  PORTD|=(1PD2)#define EEPROM_WPL  PORTD=~(1PD2) #define SPIF 7 /////////////////USRT0,USTR1  begin////////////////////////////////////////////串口begin/////////////////////////////////////////////串口0初始化void USART0_Init(){UCSR0B  =  (1  RXCIE0) |   /*接收完成中斷允許*/ // (1  TXCIE0) |   /*發(fā)送完成中斷允許*/(1  RXEN0)  |   /*接收允許*/(1  TXEN0);   /*發(fā)送允許*/UBRR0H = BAUD_H;   //設(shè)置波特率UBRR0L = BAUD_L;UCSR0C = (1  URSEL0) |  /*選擇訪問UCSRC寄存器*/(3  UCSZ00);  /*UCSZ2 UCSZ1 UCSZ0=3  8個數(shù)據(jù)位*/}//串口1初始化void USART1_Init(){UCSR1B  =  (1  RXCIE1) |   /*接收完成中斷允許*/ // (1  TXCIE1) |   /*發(fā)送完成中斷允許*/(1  RXEN0)  |   /*接收允許*/(1  TXEN0);   /*發(fā)送允許*/UBRR1H = BAUD_H;    //設(shè)置波特率UBRR1L = BAUD_L;UCSR1C = (1  URSEL1) |  /*選擇訪問UCSRC寄存器*/(3  UCSZ10);  /*UCSZ2 UCSZ1 UCSZ0=3  8個數(shù)據(jù)位*/}//串口0查詢方式發(fā)送數(shù)據(jù)void USART0_Transmit(unsigned char data){while(!(UCSR0A(1UDRE0))); /*等待發(fā)送緩沖器為空。UDRE數(shù)據(jù)寄存器空標(biāo)志位，當(dāng)發(fā)送緩沖器空時被置1；發(fā)送緩沖器包含需要發(fā)送的數(shù)據(jù)時清零*/UDR0=data;  //將數(shù)據(jù)放入緩沖器，發(fā)送數(shù)據(jù)}//串口1查詢方式發(fā)送數(shù)據(jù)void USART1_Transmit(unsigned char data){while(!(UCSR1A(1UDRE1))); /*等待發(fā)送緩沖器為空。UDRE數(shù)據(jù)寄存器空標(biāo)志位，當(dāng)發(fā)送緩沖器空時被置1；發(fā)送緩沖器包含需要發(fā)送的數(shù)據(jù)時清零*/UDR1=data;  //將數(shù)據(jù)放入緩沖器，發(fā)送數(shù)據(jù)}/*//發(fā)送GPRS命令給手機(jī)模塊void USART1_Tx_Str(char *s,unsigned char cnt){while(cnt--){USART1_Transmit(*s);s++;}}*///////////////////////////串口end//////////////////////////////////////*unsigned char usart0_receive(void){while(!(UCSR0A(1RXC0)));  //等待接收數(shù)據(jù)return UDR0;    //從緩沖器中獲取并返回數(shù)據(jù)}*/////////////USRT1,USRT2 end//////////////////////////////////////////GPRS begin//////////////////////////////////////延時ms/*void delayms(unsigned int ms){unsigned int i,j;for(i=0;ims;i++)for(j=0;j3500;j++) ;}//GPRS開機(jī)void GPRS_On(){GPRS_RSTH;  GPRS_ONOFFH; delayms(20);GPRS_RSTL;  delayms(10);GPRS_ONOFFL;LED1L;LED2L;LED3L;delayms(1800);GPRS_ONOFFH;LED1H;LED2H;LED3H;delayms(200);LED1L;LED2L;}//GPRS關(guān)機(jī)void GPRS_Off(){GPRS_ONOFFL;delayms(1800);GPRS_ONOFFH;delayms(5000);GPRS_RSTL;}//GPRS復(fù)位void GPRS_Rst(){GPRS_Off();GPRS_On();}*//////////////////GPRS end////////////////////////////////////////////////////////////eeprom  begin//////////////////////////////////////void SPI_MasterInit(void){EEPROM_WPH;delayms(20);SPCR =(1SPE)|(1MSTR)|(1SPR1)|(1SPR0);/*使能SPI，選擇主機(jī)模式，SCK=fosc/128，選擇SPI模式CPOL=0，CPHA=0*/}unsigned char SPI_MasterTransmit(unsigned char cData){//啟動數(shù)據(jù)傳輸SPDR = cData;//等待數(shù)據(jù)傳輸結(jié)束while(!(SPSR(1SPIF)));//發(fā)送完成后，清除發(fā)送標(biāo)志//  SPSR=~(1SPIF);return SPDR;//每次發(fā)送數(shù)據(jù)的同時，也會接收到數(shù)據(jù)。}//EEPROM寫使能void EEPROM_WREN(){EEPROM_CSL; //拉低片選端SPI_MasterTransmit(0x06); //0x06為寫使能的指令EEPROM_CSH; //抬高片選端，結(jié)束}//EEPROM寫禁止void EEPROM_WRDI(){EEPROM_CSL;//delayms(20);SPI_MasterTransmit(0x04); //0x04為寫禁止的指令EEPROM_CSH;//delayms(20);}//寫狀態(tài)寄存器void EEPROM_WRSR(){EEPROM_WREN();EEPROM_CSL; //使能SPI_MasterTransmit(0x01);  //0x01為寫狀態(tài)寄存器的指令SPI_MasterTransmit(0x82);  //把0x82寫入狀態(tài)寄存器EEPROM_CSH; //抬高片選，結(jié)束}/*讀狀態(tài)寄存器。讀SPI從機(jī)數(shù)據(jù)時，主機(jī)要給從機(jī)發(fā)送任意數(shù)據(jù)，才能收到從機(jī)返回的數(shù)據(jù).即0x00可以是任何數(shù)據(jù)（但是不能是25256的指令，例如0x01,0x04之類的）*/unsigned char EEPROM_RDSR(){unsigned char StatusReg;EEPROM_WREN();//  EEPROM_WRDI();  //如使用此句，不使用EEPROM_WREN()，則讀出0x80EEPROM_CSL; //使能SPI_MasterTransmit(0x05); //0x05為讀狀態(tài)寄存器指令StatusReg=SPI_MasterTransmit(0x00); //給25256發(fā)送任意數(shù)據(jù)/*此處原為：SPDR = 0x00;while(!(SPSR(1SPIF)));StatusReg=SPDR;時出錯，讀出數(shù)據(jù)都為0xff。想不清楚為什么*/EEPROM_CSH;return StatusReg;}//25256字節(jié)寫void EEPROM_ByteWrite(unsigned int Address,unsigned char Data){EEPROM_WREN();EEPROM_CSL; //使能SPI_MasterTransmit(0x02); //0x02為寫指令SPI_MasterTransmit(Address/256); //地址高位SPI_MasterTransmit(Address%256); //地址低位SPI_MasterTransmit(Data); //寫入數(shù)據(jù)  EEPROM_CSH;delayms(50);}//25256頁寫。試驗結(jié)果，只能連續(xù)寫入三個字節(jié)void EEPROM_PageWrite(unsigned int Address,

unsigned char *Data,unsigned char NData){unsigned char i;EEPROM_WREN();EEPROM_CSL;SPI_MasterTransmit(0x02);//頁寫指令SPI_MasterTransmit(Address/256); //地址高位SPI_MasterTransmit(Address%256); //地址低位for(i=0;iNData;i++){SPI_MasterTransmit(*Data); //寫入數(shù)據(jù) Data++;} EEPROM_CSH;}//25256讀unsigned char EEPROM_Read(unsigned int Address){unsigned char dataa;EEPROM_CSL; //使能SPI_MasterTransmit(0x03); //0x03為讀25256的指令SPI_MasterTransmit(Address/256); //地址高位SPI_MasterTransmit(Address%256); //地址低位dataa=SPI_MasterTransmit(0x00);//發(fā)送任意數(shù)據(jù)EEPROM_CSH;return dataa;  //返回讀到的數(shù)據(jù)}///////////////////eeprom  end//////////////////////////////////////////端口初始化void Port_Init(){PORTA=0xff;DDRA=0x30;    //PA4,PA5輸出1PORTB=0xbf;DDRB=0xb7;    

//PB1輸出1，PB2輸出1，PB3輸入0，PB4輸出1,PB0輸出1(用于新終端開關(guān)電源控制),

PB5PB7為輸出1PORTC=0xff;DDRC=0xd0;    //PC4輸出1，PC6,PC7輸出1PORTD=0xff;DDRD=0x26;    //PD0輸入0，PD1輸出1，PD5PD2輸出1}void main(void){// unsigned char dataa,i,j;SREG=0x80;  //開放全局中斷Port_Init();USART0_Init();USART1_Init();//  GPRS_On();SPI_MasterInit();EEPROM_WRSR();while(1){USART0_Transmit(0x22);USART0_Transmit(0x33);EEPROM_ByteWrite(0x2030,0x48); //給25256地址0x2030寫入數(shù)據(jù)0x48USART0_Transmit(EEPROM_Read(0x2010)); USART0_Transmit(EEPROM_Read(0x2030));

//讀出地址0x2030中數(shù)據(jù)，從串口0發(fā)送出來USART0_Transmit(0x44);USART0_Transmit(0x55);USART0_Transmit(EEPROM_RDSR());EEPROM_PageWrite(0x1001,"456789",6); 

//輸出結(jié)果0xff，0xff，0xff，0x37，0x38，0x39USART0_Transmit(EEPROM_Read(0x1001));USART0_Transmit(EEPROM_Read(0x1002));USART0_Transmit(EEPROM_Read(0x1003));USART0_Transmit(EEPROM_Read(0x1004));USART0_Transmit(EEPROM_Read(0x1005));USART0_Transmit(EEPROM_Read(0x1006));USART0_Transmit(0x11);}}/* //IAR中中斷的寫法#pragma vector=USART0_RXD_vect__interrupt void Usart0Rx(void){unsigned char dataa;dataa=UDR0;usart0_transmit(dataa);}*///串行0通信接收完成中斷//ICC中中斷的寫法#pragma interrupt_handler USART0Rx:20void USART0Rx(){unsigned char data0;data0=UDR0;USART0_Transmit(data0);}/*串行1通信接收完成中斷分析燈不亮原因，開了串口1中斷，但是沒有加入中斷函數(shù)，導(dǎo)致其他地方不能工作。串口中斷0能執(zhí)行，是由于其優(yōu)先級比串口中斷1高以下是書上的說法:接收結(jié)束標(biāo)志位(RXC)用來說明接收緩沖器中是否有未讀出的數(shù)據(jù)。

當(dāng)接收緩沖器中有未讀出的數(shù)據(jù)時，此位為1，當(dāng)接收緩沖器空時為0(即不包含未讀出的數(shù)據(jù))。

如果接收器被禁止(RXEN=0)，接收緩沖器會被刷新，從而使RXC清零。置位UCSRB的接收結(jié)束中斷使能位(RXCIE)后，

只要RXC標(biāo)志置位(且全局中斷使能)就會產(chǎn)生USART接收結(jié)束中斷。使用中斷方式進(jìn)行數(shù)據(jù)接收時，數(shù)據(jù)接收結(jié)束中斷服務(wù)程序必須從UDR讀取數(shù)據(jù)以清除RXC標(biāo)志，否則只要中斷處理程序結(jié)束，一個新的中斷就會產(chǎn)生。終上所述，RXC標(biāo)志未清零，導(dǎo)致中斷一直產(chǎn)生。*/#pragma interrupt_handler USART1Rx:21void USART1Rx(){unsigned char data1;data1=UDR1;//  USART1_Transmit(data1);}