Nios II 的PIO端口模拟I2C时序

#include <io.h> #include <stdio.h> #include <system.h> #include <alt_types.h> #include "altera_avalon_pio_regs.h" #include <unistd.h> #define DELAY_TIME 1 #define Set_SDA IOWR_ALTERA_AVALON_PIO_DATA(SDA_BASE, 0x1) #define Clr_SDA IOWR_ALTERA_AVALON_PIO_DATA(SDA_BASE, 0x0) #define Set_SCL IOWR_ALTERA_AVALON_PIO_DATA(SCL_BASE, 0x1) #define Clr_SCL IOWR_ALTERA_AVALON_PIO_DATA(SCL_BASE, 0x0) //void delay(unsigned int value) //{ // unsigned int i; // for(i=0;i<value;i++) // ; //} void I2C_Start(void) { /* SDA -------_________ SCL ------------____ */ IOWR_ALTERA_AVALON_PIO_DIRECTION(SDA_BASE, 0x1); Set_SDA; //SDA = 1 Set_SCL; //SCL = 1 usleep(DELAY_TIME); Clr_SDA; //SDA = 0 usleep(DELAY_TIME); Clr_SCL; //SCL = 0 usleep(DELAY_TIME); } void I2C_Send_Byte(unsigned char data) { /* MSB SDA ______-------------__________ SCL _________-------_____________ */ unsigned char i = 8; IOWR_ALTERA_AVALON_PIO_DIRECTION(SDA_BASE, 0x1); //IOWR_ALTERA_AVALON_PIO_DIRECTION(SCL_BASE, 0x1); Clr_SDA; Clr_SCL; usleep(DELAY_TIME); while( i-- ) { if (data&0x80) Set_SDA; else Clr_SDA; usleep(DELAY_TIME); Set_SCL; usleep(DELAY_TIME); Clr_SCL; usleep(1); Clr_SDA; usleep(DELAY_TIME); data = data << 1; } } void Check_Ack(void) { /* SDA ____zzzzzzzzzzzzz SCL ____------_______ */ unsigned char a=1; IOWR_ALTERA_AVALON_PIO_DIRECTION(SDA_BASE, 0x0); //IOWR_ALTERA_AVALON_PIO_DIRECTION(SCL_BASE, 0x1); //Set_SDA; // SDA = "Z" for input model a = 1; usleep(DELAY_TIME); Set_SCL; // SCL = 1 //usleep(DELAY_TIME); a=IORD_ALTERA_AVALON_PIO_DATA(SDA_BASE); usleep(DELAY_TIME); /* Clr_SCL; delay(DELAY_TIME); if(a==1) printf("not receive ack\n"); else printf("receive ack\n"); */ while(a) { a=IORD_ALTERA_AVALON_PIO_DATA(SDA_BASE); usleep(DELAY_TIME); } Clr_SCL; IOWR_ALTERA_AVALON_PIO_DIRECTION(SDA_BASE, 0x1); Clr_SDA; usleep(40); } void I2C_Stop(void) { /* SDA _________-------- SCL ____------------- */ IOWR_ALTERA_AVALON_PIO_DIRECTION(SDA_BASE, 0x1); //IOWR_ALTERA_AVALON_PIO_DIRECTION(SCL_BASE, 0x1); usleep(2); Clr_SDA; //SDA = 0 Clr_SCL; //SCL = 0 usleep(3); Set_SCL; //SCL = 1 usleep(3); Set_SDA; //SDA = 1 usleep(3); Clr_SCL; //SCL = 0 usleep(3); } unsigned char I2C_Receive_Byte(void) { unsigned char rn = 0, data=0,rr=0x80; IOWR_ALTERA_AVALON_PIO_DIRECTION(SDA_BASE, 0x0); //input model //IOWR_ALTERA_AVALON_PIO_DIRECTION(SCL_BASE, 0x1); Clr_SCL; //Set_SDA; //SDA = "Z" usleep(DELAY_TIME); for(rn=0;rn<8;rn++) { Set_SCL; usleep(DELAY_TIME); if (IORD_ALTERA_AVALON_PIO_DATA(SDA_BASE)) data|=rr; else data&=~rr; usleep(DELAY_TIME); rr>>=1; Clr_SCL; usleep(DELAY_TIME); } usleep(5); return data; } //void I2C_Ack(void) //{ // /* SDA _________________ // SCL ____------_______ */ // IOWR_ALTERA_AVALON_PIO_DIRECTION(SDA_BASE, 0x1); // IOWR_ALTERA_AVALON_PIO_DIRECTION(SCL_BASE, 0x1); // Clr_SDA; // delay(DELAY_TIME); // Set_SCL; // delay(DELAY_TIME); // Clr_SCL; // delay(DELAY_TIME); //} void I2C_Nack(void) { /* SDA ___--------_____ SCL ____------_______ */ IOWR_ALTERA_AVALON_PIO_DIRECTION(SDA_BASE, 0x1); //IOWR_ALTERA_AVALON_PIO_DIRECTION(SCL_BASE, 0x1); Set_SDA; usleep(DELAY_TIME); Set_SCL; usleep(DELAY_TIME); Clr_SCL; usleep(1); Clr_SDA; usleep(DELAY_TIME); } //---------------------------------------------------------------------------- //write a byte data in ram //---------------------------------------------------------------------------- void single_byte_write(unsigned char MSB, unsigned char LSB, unsigned char DATA) { I2C_Start(); I2C_Send_Byte(0xa0); Check_Ack(); I2C_Send_Byte(MSB); Check_Ack(); I2C_Send_Byte(LSB); Check_Ack(); I2C_Send_Byte(DATA); Check_Ack(); I2C_Stop(); } //---------------------------------------------------------------------------- //read a byte data from ram //---------------------------------------------------------------------------- unsigned char single_byte_read(unsigned char MSB) { unsigned char data_temp; I2C_Start(); I2C_Send_Byte(0xba); Check_Ack(); I2C_Send_Byte(MSB); // Check_Ack(); // I2C_Send_Byte(LSB); Check_Ack(); I2C_Start(); I2C_Send_Byte(0xbb); Check_Ack(); data_temp = I2C_Receive_Byte(); I2C_Nack(); I2C_Stop(); return data_temp; } //write multiply byte into RAMTRON void write_multi_byte (unsigned char MSB, unsigned char LSB, unsigned char *pdata) { unsigned char data_size = 0; unsigned char temp_data = (*pdata); unsigned char i; while(temp_data > 0 ) { data_size++; temp_data = *(pdata + 1); } I2C_Start(); I2C_Send_Byte(0xa0); Check_Ack(); I2C_Send_Byte(MSB); Check_Ack(); I2C_Send_Byte(LSB); Check_Ack(); //write data for(i = 0; i < data_size; i++) { I2C_Send_Byte(*(pdata + i)); Check_Ack(); } I2C_Stop(); } //read multi byte from RAMTRON