TWI.rar_AVR IIC

#include "iom16v.h" #define uchar unsigned char #define uint unsigned int #define wr_device_add 0x64 //8025 器件地址，写命令 #define rd_device_add 0x65 //器件地址，读命令 #define START 0x08 // #define RE_START 0x10 #define MT_SLA_ACK 0x18 #define MT_DATA_ACK 0x28 #define MR_SLA_ACK 0x40 #define MR_DATA_ACK 0x50 #define MR_DATA_NAK 0x58 #define Start() (TWCR=(1<<TWINT)|(1<<TWSTA)|(1<<TWEN)) #define Stop() (TWCR=(1<<TWINT)|(1<<TWSTO)|(1<<TWEN)) #define Wait() {while(!(TWCR&(1<<TWINT)));} #define TestAck() (TWSR&0xf8) #define SetAck() (TWCR|=(1<<TWEA)) #define SetNoAck() (TWCR&=~(1<<TWEA)) #define Twi() (TWCR=(1<<TWINT)|(1<<TWEN)) #define Write8Bit(x) {TWDR=(x);TWCR=(1<<TWINT)|(1<<TWEN);} uchar now_time[6]; //Twi 初始化 void Twi_init(void) { TWSR=00; TWBR=0x16; //50K } /****************************************** Twi总线写一个字节 返回0:写成功 返回非0:写失败 *******************************************/ unsigned char i2c_Write(unsigned char Wdata,unsigned int RomAddress) { Start();//I2C启动 Wait(); if(TestAck()!=START) return 1;//ACK Write8Bit(wr_device_add);//写I2C从器件地址和写方式 Wait(); if(TestAck()!=MT_SLA_ACK) return 1;//ACK Write8Bit(RomAddress);//写地址 Wait(); if(TestAck()!=MT_DATA_ACK) return 1;//ACK Write8Bit(Wdata);//写数据 Wait(); if(TestAck()!=MT_DATA_ACK) return 1;//ACK Stop();//I2C停止 delay_ms(10);//延时 return 0; } /****************************************** Twi总线读一个字节 如果读失败也返回0 *******************************************/ unsigned char i2c_Read(unsigned int RomAddress) { unsigned char temp; Start();//I2C启动 Wait(); if (TestAck()!=START) return 0;//ACK Write8Bit(wr_device_add);//写I2C从器件地址和写方式 Wait(); if (TestAck()!=MT_SLA_ACK) return 0;//ACK Write8Bit(RomAddress);//写地址 Wait(); if (TestAck()!=MT_DATA_ACK) return 0; Start();//I2C重新启动 Wait(); if (TestAck()!=RE_START) return 0; Write8Bit(rd_device_add);//写I2C从器件地址和读方式 Wait(); if(TestAck()!=MR_SLA_ACK) return 0;//ACK Twi();//启动主I2C读方式 Wait(); if(TestAck()!=MR_DATA_NAK) return 0;//ACK temp=TWDR;//读取I2C接收数据 Stop();//I2C停止 return temp; } Void main(void) { uchar i, j,time_temp; while(1) { //测试时钟 USART_Transmit('t'); USART_Transmit('i'); USART_Transmit('m'); USART_Transmit('e'); USART_Transmit('-'); USART_Transmit('t'); USART_Transmit('e'); USART_Transmit('s'); USART_Transmit('t'); USART_Transmit(':'); //写时钟 i2c_Write(now_time[0],0x60); //年 i2c_Write(now_time[1],0x50); //月 i2c_Write(now_time[2],0x40); //日 i2c_Write(now_time[3],0x20); //时 i2c_Write(now_time[4],0x10); //分 i2c_Write(now_time[5],0x00); //秒 //读时钟 delay_ms(500); USART_Transmit(0x20); time_temp=i2c_Read(0x60); //年 USART_Transmit(time_temp); time_temp=i2c_Read(0x50); //月 USART_Transmit(time_temp); time_temp=i2c_Read(0x40); //日 USART_Transmit(time_temp); time_temp=i2c_Read(0x20); //时 USART_Transmit(time_temp); time_temp=i2c_Read(0x10); //分 USART_Transmit(time_temp); time_temp=i2c_Read(0x00); //秒 USART_Transmit(time_temp); /* 等待接收数据(需要设置的),存入now_time[]中 */ while(!(UCSRA & (1<<RXC))); //等待UART接收数据 i=UDR; while(i!='y'); //如果接收到字符y则继续 } }