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#ifndef __IIC0_H_
#define __IIC0_H_
#include "common.h"
#include "delay.h"
//IIC通讯过程中的指定状态
#define STATUS_SENDSTART 0X08 //已经发送起始条件
#define STATUS_REPEATSTART 0X10 //已经发送重复的起始条件
#define STATUS_SENDSLAVE_ACK 0X18 //已发送从机写地址,接收到ACK
#define STATUS_SENDSLAVE_NACK 0X20 //已发送从机写地址,未接收到ack
#define STATUS_SENDDATA_ACK 0X28 //已发送从机写数据,并接收到ack
#define STATUS_SENDDATA_NACK 0X30 //已发送从机写数据没收到ack
#define STATUS_LOSS 0X38 //丢失总线仲裁
#define STATUS_READADDR_NACK 0X48 //已经发送从机读地址未收到ack
#define STATUS_READADDR_ACK 0X40 //已发送从机读地址并接受到ack
#define STATUS_RECV_ACK 0X50 //已接受数据字节ack已返回
#define STATUS_RECV_NACK 0X58 //已接受数据字节nack已返回
void iic0_init(u16 div);//参数为时钟分频数 不得超过65535 + 65535
u8 iic0_start(void);//发送起始信号
u8 iic0_send_write_addr(u8 addr);//发送设备写地址
u8 iic0_send_data(u8 data);//发送数据
u8 iic0_send_stop(void);//发送停止
u8 iic0_send_read_addr(u8 addr);//发送读地址
u8 iic0_read_data(u8* value,u8 ack);//读取数据
u8 iic0_repeat_start(void);//重新发送start
#endif
#include "iic0.h"
#define I2EN 6 //接口使能
#define STA 5 //起始标志
#define STO 4 //停止标志
#define SI 3 //中断标志
#define AA 2 //应答标志
#define I2ENC 6 //清除iic使能
#define STAC 5 //清除起始
#define SIC 3 //清除中断
#define AAC 2 //清除应答
#define STATE (LPC_I2C0->STAT & 0xf8) //IIC总线的实际状态信息
void iic0_init(u16 div)
{
//打开时钟,同时打开iic和gpio时钟
LPC_SC->PCONP |= (1<<15)|(1<<7);//打开时钟
//配置引脚功能
LPC_IOCON->P0_27 = 0x00;
LPC_IOCON->P0_27 |= (1<<0)|(1<<8);//打开iic功能,禁止滤波器 与引脚配置相关 根据实际引脚进行修改
LPC_IOCON->P0_28 = 0x00;//选择gpio功能,禁止迟滞 不反向 正常推挽
LPC_IOCON->P0_28 |= (1<<0)|(1<<8);//打开iic功能,禁止滤波器 与引脚配置相关 根据实际引脚进行修改
LPC_I2C0->CONCLR |= (1<<I2ENC);//首先禁止IIC接口
LPC_I2C0->CONCLR |= (1<<AAC)|(1<<SIC)|(1<<STAC);//清除应答,中断,起始标志
LPC_I2C0->SCLH = div/2;//设置IIC时钟
LPC_I2C0->SCLL = div/2;
LPC_I2C0->CONSET |= (1<<I2EN);//使能iic
}
//等待指定的状态
//失败返回1 成功返回0
static u8 WaitResponse(u8 response)
{
u8 retry = 200;
while(--retry)
{
DelayUs(1);
if(STATE == response)break;
}
if(retry)return 0;
else
{
iic0_send_stop();
return 1;
}
}
u8 iic0_start(void)//发送起始信号
{
LPC_I2C0->CONCLR = (1<<SIC)|(1<<STAC)|(1<<AAC);
//Start
LPC_I2C0->CONSET = (1<<STA);//发送start,等待iic 状态寄存器达到指定状态
return WaitResponse(STATUS_SENDSTART);//等待起始条件发送成功
}
u8 iic0_send_write_addr(u8 addr) //发送设备写地址
{
//dev_addr
LPC_I2C0->DAT = addr;
LPC_I2C0->CONSET = (1<<AA);//自动ack 好像这一位无关紧要现在
LPC_I2C0->CONCLR = (1<<SIC)|(1<<STAC);//停止中断与start
return WaitResponse(STATUS_SENDSLAVE_ACK);//等待设备ack
}
u8 iic0_send_data(u8 data) //发送数据
{
LPC_I2C0->DAT = data;
LPC_I2C0->CONSET = (1<<AA);//自动ack
LPC_I2C0->CONCLR = (1<<SIC)|(1<<STAC);;//清除中断和start
return WaitResponse(STATUS_SENDDATA_ACK);
}
u8 iic0_send_stop(void) //发送停止
{
LPC_I2C0->CONCLR = (1<<SIC)|(1<<STAC)|(1<<AAC);
LPC_I2C0->CONSET = (1<<STO);
LPC_I2C0->CONCLR = (1<<SIC);
return 0;
}
u8 iic0_send_read_addr(u8 addr) //发送读地址
{
LPC_I2C0->DAT = addr;
LPC_I2C0->CONSET = (1<<AA);
LPC_I2C0->CONCLR = (1<<SIC)|(1<<STAC);
return WaitResponse(STATUS_READADDR_ACK);
}
u8 iic0_read_data(u8* value,u8 ack) //读取数据 1发送ack 0不发送
{
if(ack)
{
LPC_I2C0->CONSET = (1<<AA);
LPC_I2C0->CONCLR = (1<<SIC);
if( WaitResponse(STATUS_RECV_ACK))return 1;
}
else
{
LPC_I2C0->CONCLR = (1<<AAC)|(1<<SIC);
if(WaitResponse(STATUS_RECV_NACK))return 1;
}
*value = LPC_I2C0->DAT;
return 0;
}
u8 iic0_repeat_start(void) //重新发送start
{
LPC_I2C0->CONCLR = (1<<SIC);//清除中断再次发送start
LPC_I2C0->CONSET = (1<<STA);
return WaitResponse(STATUS_REPEATSTART);//等待重复start成功
}
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原文地址：http://www.cnblogs.com/dengxiaojun/p/4338714.html
