eeprom_init._h

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/*
 I2C总线/TWI操作模块
 1、读取和写入函数
 2、地址有效范围255
 3、数据长度为单字节
 4、函数采用查询方式
 5、可直接嵌入到项目中使用
 6、晶振频率：1M
 7、总线速度：50K
 AVR_AFA
 www.iccavr.com
*/
#include "iom128v.h"
/*I2C总线主机模式错误处理*/
void error(unsigned char type) 
{
 switch (type & 0xF8) 
 {
  case 0x20:     /*址址写失败*/
   /*stop 停止*/
   TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWSTO);
   break;
  case 0x30:     /*数据写失败*/
   /*stop 停止*/
   TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWSTO);
   break;
  case 0x38:     /*仲裁失败*/
   break;
  case 0x48:     /*址址读失败*/
   /*stop 停止*/
   TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWSTO);
   break;
  }
}
/*I2C总线单字节写入*/
unsigned char twi_write(unsigned char addr, unsigned char dd) 
{
 TWBR = 2;
 /*start 启动*/
 TWCR = (1 << TWINT) | (1 << TWSTA) | (1 << TWEN);
 while (!(TWCR & (1 << TWINT)));
 if ((TWSR & 0xF8) != 0x08) {
  error(TWSR);
  return 0;
  }
 /*SLA_W 芯片地址*/
 TWDR = 0xA0;
 TWCR = (1 << TWINT) | (1 << TWEN);
 while (!(TWCR & (1 << TWINT)));
 if ((TWSR & 0xF8) != 0x18) {
  error(TWSR);
  return 0;
  }
 /*addr 操作地址*/
 TWDR = addr;
 TWCR = (1 << TWINT) | (1 << TWEN);
 while (!(TWCR & (1 << TWINT)));
 if ((TWSR & 0xF8) != 0x28) {
  error(TWSR);
  return 0;
  }
 
 /*dd 写入数据*/
 TWDR = dd;
 TWCR = (1 << TWINT) | (1 << TWEN);
 while (!(TWCR & (1 << TWINT)));
 if ((TWSR & 0xF8) != 0x28) {
  error(TWSR);
  return 0;
  }
 
 /*stop 停止*/
 TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWSTO);
 return 1;
}
/*I2C总线单字节读取*/
unsigned char twi_read(unsigned char addr, unsigned char *dd) 
{
 TWBR = 2;
 /*start 启动*/
 TWCR=(1<<TWINT)|(1<<TWSTA)|(1<<TWEN);
 while(!(TWCR&(1<<TWINT)));
 if ((TWSR & 0xF8) != 0x08) {
  error(TWSR);
  return 0;
  }
 /*SLA_W 芯片地址*/
 TWDR = 0xA0;
 TWCR = (1 << TWINT) | (1 << TWEN);
 while (!(TWCR & (1 << TWINT)));
 if ((TWSR & 0xF8) != 0x18) {
  error(TWSR);
  return 0;
  }
 /*addr 操作地址*/
 TWDR = addr;
 TWCR = (1 << TWINT) | (1 << TWEN);
 while (!(TWCR & (1 << TWINT)));
 if ((TWSR & 0xF8) != 0x28) {
  error(TWSR);
  return 0;
  }
  
 /*start 启动*/
 TWCR = (1 << TWINT) | (1 << TWSTA) | (1 << TWEN);
 while (!(TWCR & (1 << TWINT)));
 if ((TWSR & 0xF8) != 0x10) {
  error(TWSR);
  return 0;
  }
 
 /*SLA_R 芯片地址*/
 TWDR = 0xA1;
 TWCR = (1 << TWINT) | (1 << TWEN);
 while (!(TWCR & (1 << TWINT)));
 if ((TWSR & 0xF8) != 0x40) {
  error(TWSR);
  return 0;
  }
 /*读取数据*/
 TWCR = (1 << TWINT) | (1 << TWEN);
 while (!(TWCR & (1 << TWINT)));
 if ((TWSR & 0xF8) != 0x58) {
  error(TWSR);
  return 0;
  }
 *dd = TWDR;
  
 /*stop 停止*/
 TWCR = (1 << TWINT) | (1 << TWSTO) | (1 << TWEN);
 return 1;
}