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硬件中斷方式I2C(CVAVR)

作者：時間：2016-11-18 來源：網絡

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//i2c.h

#defineTWPS00
#defineTWPS11
#defineTWEN2
#defineTWIE0
#defineTWEA6
#defineTWINT7
#defineTWSTA5
#defineTWSTO4

//TWSRvalues(notbits)
//Master
#defineTW_START0x08
#defineTW_REP_START0x10
//MasterTransmitter
#defineTW_MT_SLA_ACK0x18
#defineTW_MT_SLA_NACK0x20
#defineTW_MT_DATA_ACK0x28
#defineTW_MT_DATA_NACK0x30
#defineTW_MT_ARB_LOST0x38
//MasterReceiver
#defineTW_MR_ARB_LOST0x38
#defineTW_MR_SLA_ACK0x40
#defineTW_MR_SLA_NACK0x48
#defineTW_MR_DATA_ACK0x50
#defineTW_MR_DATA_NACK0x58
//SlaveTransmitter
#defineTW_ST_SLA_ACK0xA8
#defineTW_ST_ARB_LOST_SLA_ACK0xB0
#defineTW_ST_DATA_ACK0xB8
#defineTW_ST_DATA_NACK0xC0
#defineTW_ST_LAST_DATA0xC8
//SlaveReceiver
#defineTW_SR_SLA_ACK0x60
#defineTW_SR_ARB_LOST_SLA_ACK0x68
#defineTW_SR_GCALL_ACK0x70
#defineTW_SR_ARB_LOST_GCALL_ACK0x78
#defineTW_SR_DATA_ACK0x80
#defineTW_SR_DATA_NACK0x88
#defineTW_SR_GCALL_DATA_ACK0x90
#defineTW_SR_GCALL_DATA_NACK0x98
#defineTW_SR_STOP0xA0
//Misc
#defineTW_NO_INFO0xF8
#defineTW_BUS_ERROR0x00

//definesandconstants
#defineTWCR_CMD_MASK0x0F
#defineTWSR_STATUS_MASK0xF8

//returnvalues
#defineI2C_OK0x00
#defineI2C_ERROR_NODEV0x01

#defineI2C_SEND_DATA_BUFFER_SIZE0x20
#defineI2C_RECEIVE_DATA_BUFFER_SIZE0x20

#defineF_CPU8000000
#defineTRUE1
#defineFALSE0
//types
typedefenum
{
I2C_IDLE=0,I2C_BUSY=1,
I2C_MASTER_TX=2,I2C_MASTER_RX=3,
I2C_SLAVE_TX=4,I2C_SLAVE_RX=5
}eI2cStateType;

//i2c.c
#include
#include"i2c.h"

//I2C標準波特率:
//低速100KHz
//高速400KHz

//I2C狀態和地址變量
staticvolatileeI2cStateTypeI2cState;
staticunsignedcharI2cDeviceAddrRW;
//發送緩沖區
staticunsignedcharI2cSendData[I2C_SEND_DATA_BUFFER_SIZE];
staticunsignedcharI2cSendDataIndex;
staticunsignedcharI2cSendDataLength;
//接收緩沖區
staticunsignedcharI2cReceiveData[I2C_RECEIVE_DATA_BUFFER_SIZE];
staticunsignedcharI2cReceiveDataIndex;
staticunsignedcharI2cReceiveDataLength;

unsignedcharlocalBuffer[]="!!";
unsignedcharlocalBufferLength=0x20;

//指向接收處理函數的指針，當本機被選中從接收時調用函數：I2cSlaveReceive
staticvoid(*i2cSlaveReceive)(unsignedcharreceiveDataLength,unsignedchar*recieveData);
//指向發送處理函數的指針，當本機被選中從發送時調用函數：II2cSlaveTransmit
staticunsignedchar(*i2cSlaveTransmit)(unsignedchartransmitDataLengthMax,unsignedchar*transmitData);

//設置總線速率
voidi2cSetBitrate(unsignedintbitrateKHz)
{
unsignedcharbitrate_div;
//SCLfreq=F_CPU/(16+2*TWBR))
#ifdefTWPS0
//對于用速率分頻的AVR(mega128)
//SCLfreq=F_CPU/(16+2*TWBR*4^TWPS)
//setTWPStozero
TWSR&=~(1<TWSR&=~(1<#endif
//計算分頻
bitrate_div=((F_CPU/1000l)/bitrateKHz);
if(bitrate_div>=16)
bitrate_div=(bitrate_div-16)/2;
TWBR=bitrate_div;
}

//總線初始化
voidi2cInit(void)
{
//設置總線上拉
#ifdef_MEGA128_INCLUDED_
//#ifdef_MEGA64_INCLUDED_
PORTD.0=1;//i2cSCLonATmega128,64
PORTD.1=1;//i2cSDAonATmega128,64
#else
PORTC.0=1;//i2cSCLonATmega163,323,16,32,等
PORTC.1=1;//i2cSDAonATmega163,323,16,32,等
#endif
//清空從發送和從接受
i2cSlaveReceive=0;
i2cSlaveTransmit=0;
//設置i2c波特率為100KHz
i2cSetBitrate(100);
//I2C總線使能
TWCR|=1<//狀態設置
I2cState=I2C_IDLE;
//開I2C中斷和回應
TWCR|=1<TWCR|=1<
#asm("sei");
}

voidi2cSetLocalDeviceAddr(unsignedchardeviceAddr,unsignedchargenCallEn)
{
//設置本機從地址(從方式時)
TWAR=(deviceAddr&0xFE)|(genCallEn?1:0);
}

voidi2cSetSlaveReceiveHandler(void(*i2cSlaveRx_func)(unsignedcharreceiveDataLength,unsignedchar*recieveData))
{
i2cSlaveReceive=i2cSlaveRx_func;
}

voidi2cSetSlaveTransmitHandler(unsignedchar(*i2cSlaveTx_func)(unsignedchartransmitDataLengthMax,unsignedchar*transmitData))
{
i2cSlaveTransmit=i2cSlaveTx_func;
}

inlinevoidi2cSendStart(void)
{

TWCR=TWCR&TWCR_CMD_MASK|(1<}

inlinevoidi2cSendStop(void)
{
//發送停止條件，保持TWEA以便從接收
TWCR=TWCR&TWCR_CMD_MASK|(1<}

inlinevoidi2cWaitForComplete(void)
{
//等待i2c總線操作完成
while(!(TWCR&(1<}

inlinevoidi2cSendByte(unsignedchardata)
{
//裝載數據到TWDR
TWDR=data;
//發送開始
TWCR=TWCR&TWCR_CMD_MASK|(1<}

inlinevoidi2cReceiveByte(unsignedcharackFlag)
{
//開始通過i2c接收
if(ackFlag)
{
//ackFlag=TRUE:數據接收后回應ACK
TWCR=TWCR&TWCR_CMD_MASK|(1<}
else
{
//ackFlag=FALSE:數據接收后無回應
TWCR=TWCR&TWCR_CMD_MASK|(1<}
}

inlineunsignedchari2cGetReceivedByte(void)
{
//返回接收到的數據
return(TWDR);
}

inlineunsignedchari2cGetStatus(void)
{
//返回總線狀態
return(TWSR);
}

voidi2cMasterSend(unsignedchardeviceAddr,unsignedcharlength,unsignedchar*data)
{
unsignedchari;
//等待總線準備完成
while(I2cState);
//設置狀態
I2cState=I2C_MASTER_TX;
//準備數據
I2cDeviceAddrRW=(deviceAddr&0xFE);//RW為0:寫操作
for(i=0;iI2cSendData[i]=*data++;
I2cSendDataIndex=0;
I2cSendDataLength=length;
//發送開始條件
i2cSendStart();
}

voidi2cMasterReceive(unsignedchardeviceAddr,unsignedcharlength,unsignedchar*data)
{
unsignedchari;
//等待總線準備完成
while(I2cState);
//設置狀態
I2cState=I2C_MASTER_RX;
//保存數據
I2cDeviceAddrRW=(deviceAddr|0x01);//RW為1:讀操作
I2cReceiveDataIndex=0;
I2cReceiveDataLength=length;
//發送開始條件
i2cSendStart();
//等待數據準備好
while(I2cState);
//取數據
for(i=0;i*data++=I2cReceiveData[i];
}

unsignedchari2cMasterSendNI(unsignedchardeviceAddr,unsignedcharlength,unsignedchar*data)
{
unsignedcharretval=I2C_OK;

//關I2C中斷
TWCR&=~(1<
//發送開始條件
i2cSendStart();
i2cWaitForComplete();

//發送器件寫地址
i2cSendByte(deviceAddr&0xFE);
i2cWaitForComplete();

//檢查器件是否可用
if(TWSR==TW_MT_SLA_ACK)
{
//發送數據
while(length)
{
i2cSendByte(*data++);
i2cWaitForComplete();
length--;
}
}
else
{
//如未回應器件地址，停止發送，返回錯誤

retval=I2C_ERROR_NODEV;
}

//發送停止條件，保持TWEA以便從接收
i2cSendStop();
while(!(TWCR&(1<
//開I2C中斷
TWCR|=(1<
returnretval;
}

unsignedchari2cMasterReceiveNI(unsignedchardeviceAddr,unsignedcharlength,unsignedchar*data)
{
unsignedcharretval=I2C_OK;

//關I2C中斷
TWCR&=~(1<
//發送開始條件
i2cSendStart();
i2cWaitForComplete();

//發送器件讀地址
i2cSendByte(deviceAddr|0x01);
i2cWaitForComplete();

//檢查器件是否可用
if(TWSR==TW_MR_SLA_ACK)
{
//接收數據并回應
while(length>1)
{
i2cReceiveByte(TRUE);
i2cWaitForComplete();
*data++=i2cGetReceivedByte();
length--;
}

//接收數據無回應(末位信號)
i2cReceiveByte(FALSE);
i2cWaitForComplete();
*data++=i2cGetReceivedByte();
}
else
{
//如未回應器件地址，停止發送，返回錯誤
retval=I2C_ERROR_NODEV;
}

//發送停止條件，保持TWEA以便從接收
i2cSendStop();

//開I2C中斷
TWCR|=TWIE;

returnretval;
}

eI2cStateTypei2cGetState(void)
{
returnI2cState;
}

//I2C(TWI)中斷服務程序
interrupt[TWI]voidtwi_isr(void)
{
//讀狀態位
unsignedcharstatus;
status=TWSR&TWSR_STATUS_MASK;
switch(status)
{
//主方式
caseTW_START://0x08:START已發送
caseTW_REP_START://0x10:重復START已發送
//發送器件地址
i2cSendByte(I2cDeviceAddrRW);
break;

//主發送，主接收狀態碼
caseTW_MT_SLA_ACK://0x18:SLA+W已發送；接收到ACK
caseTW_MT_DATA_ACK://0x28:數據已發送；接收到ACK

if(I2cSendDataIndex{
//發送數據
i2cSendByte(I2cSendData[I2cSendDataIndex++]);
}
else
{
//發送停止條件，保持TWEA以便從接收
i2cSendStop();
//設置狀態
I2cState=I2C_IDLE;
}
break;
caseTW_MR_DATA_NACK://0x58:接收到數據；NOTACK已返回

//保存最終數據
I2cReceiveData[I2cReceiveDataIndex++]=TWDR;
//繼續發送條件
caseTW_MR_SLA_NACK://0x48:SLA+R已發送，接收到NOTACK
caseTW_MT_SLA_NACK://0x20:SLA+W已發送，接收到NOTACK
caseTW_MT_DATA_NACK://0x30:數據已發送，接收到NOTACK

//發送停止條件，保持TWEA以便從接收
i2cSendStop();
//設置狀態
I2cState=I2C_IDLE;
break;
caseTW_MT_ARB_LOST://0x38:SLA+W或數據的仲裁失敗

//釋放總線
TWCR=TWCR&TWCR_CMD_MASK|(1<//設置狀態
I2cState=I2C_IDLE;

break;
caseTW_MR_DATA_ACK://0x50:接收到數據，ACK已返回

//保存接收到的數據位
I2cReceiveData[I2cReceiveDataIndex++]=TWDR;
//檢查是否接收完
caseTW_MR_SLA_ACK://0x40:SLA+R已發送，接收到ACK

if(I2cReceiveDataIndex<(I2cReceiveDataLength-1))
//數據位將接收,回復ACK(傳送更多字節)
i2cReceiveByte(TRUE);
else
//數據位將接收,回復NACK(傳送最后字節)
i2cReceiveByte(FALSE);
break;

//從接收狀態碼
caseTW_SR_SLA_ACK://0x60:自己的SLA+W已經被接收，ACK已返回
caseTW_SR_ARB_LOST_SLA_ACK://0x68:SLA+R/W作為主機的仲裁失敗；自己的SLA+W已經被接收，ACK已返回
caseTW_SR_GCALL_ACK://0x70:接收到廣播地址，ACK已返回
caseTW_SR_ARB_LOST_GCALL_ACK://0x78:SLA+R/W作為主機的仲裁失敗；接收到廣播地址，ACK已返回

//被選中為從寫入(數據將從主機接收)
//設置狀態
I2cState=I2C_SLAVE_RX;
//緩沖準備
I2cReceiveDataIndex=0;
//接收數據，回應ACK
TWCR=TWCR&TWCR_CMD_MASK|(1<break;
caseTW_SR_DATA_ACK://0x80:以前以自己的SLA+W被尋址；數據已經被接收，ACK已返回
caseTW_SR_GCALL_DATA_ACK://0x90:以前以廣播方式被尋址；數據已經被接收，ACK已返回

I2cReceiveData[I2cReceiveDataIndex++]=TWDR;
//檢查接收緩沖區狀態
if(I2cReceiveDataIndex{
//接收數據，回應ACK
i2cReceiveByte(TRUE);
}
else
{
//接收數據，回應NACK
i2cReceiveByte(FALSE);
}
break;
caseTW_SR_DATA_NACK://0x88:以前以自己的SLA+W被尋址；數據已經被接收，NOTACK已返回
caseTW_SR_GCALL_DATA_NACK://0x98:以前以廣播方式被尋址；數據已經被接收，NOTACK已返回

//接收數據，回應NACK
i2cReceiveByte(FALSE);
break;
caseTW_SR_STOP://0xA0:在以從機工作時接收到STOP或重復START
TWCR=TWCR&TWCR_CMD_MASK|(1<//i2c接收完成
if(i2cSlaveReceive)
i2cSlaveReceive(I2cReceiveDataIndex,I2cReceiveData);
//設置狀態
I2cState=I2C_IDLE;
break;

//從發送
caseTW_ST_SLA_ACK://0xA8:自己的SLA+R已經被接收，ACK已返回
caseTW_ST_ARB_LOST_SLA_ACK://0xB0:SLA+R/W作為主機的仲裁失敗；自己的SLA+R已經被接收，ACK已返回

//被選中為從讀出(數據將從傳回主機)
//設置狀態
I2cState=I2C_SLAVE_TX;
//數據請求
if(i2cSlaveTransmit)I2cSendDataLength=i2cSlaveTransmit(I2C_SEND_DATA_BUFFER_SIZE,I2cSendData);
I2cSendDataIndex=0;
//
caseTW_ST_DATA_ACK://0xB8:TWDR里數據已經發送，接收到ACK

//發送數據位
TWDR=I2cSendData[I2cSendDataIndex++];
if(I2cSendDataIndex//回應ACK
TWCR=TWCR&TWCR_CMD_MASK|(1<else
//回應NACK
TWCR=TWCR&TWCR_CMD_MASK|(1<break;
caseTW_ST_DATA_NACK://0xC0:TWDR里數據已經發送接收到NOTACK
caseTW_ST_LAST_DATA://0xC8:TWDR的一字節數據已經發送(TWAE=“0”);接收到ACK

//全部完成
//從方式開放
TWCR=TWCR&TWCR_CMD_MASK|(1<//設置狀態
I2cState=I2C_IDLE;
break;

caseTW_NO_INFO://0xF8:沒有相關的狀態信息；TWINT=“0”
//無操作

break;
caseTW_BUS_ERROR://0x00:由于非法的START或STOP引起的總線錯誤

//內部硬件復位，釋放總線
TWCR=TWCR&TWCR_CMD_MASK|(1<//設置狀態
I2cState=I2C_IDLE;
break;
}
}

//從操作
voidi2cSlaveReceiveService(unsignedcharreceiveDataLength,unsignedchar*receiveData)
{
unsignedchari;
//此函數在本機被選中為從寫入時運行
//接收到的數據存入本地緩沖區
for(i=0;i{
localBuffer[i]=*receiveData++;
}
localBufferLength=receiveDataLength;

}

unsignedchari2cSlaveTransmitService(unsignedchartransmitDataLengthMax,unsignedchar*transmitData)
{
unsignedchari;

//此函數在本機被選中為從讀出時運行
//要發送的數據存入發送緩沖區
for(i=0;i{
*transmitData++=localBuffer[i];
}

localBuffer[0]++;

returnlocalBufferLength;
}

#defineTARGET_ADDR0xA0
//測試(24xxyy器件)
voidtestI2cMemory(void)
{
unsignedchari;
unsignedchartxdata[66];
unsignedcharrxdata[66];

txdata[0]=0;
txdata[1]=0;

for(i=0;i<16;i++)
txdata[2+i]=localBuffer[i];
//發送地址和數據
i2cMasterSendNI(TARGET_ADDR,18,txdata);

txdata[18]=0;

//發送地址
i2cMasterSendNI(TARGET_ADDR,2,txdata);
//接收數據
i2cMasterReceiveNI(TARGET_ADDR,16,rxdata);
//
rxdata[16]=0;

}

voidmain(void)
{
i2cInit();
//設置從接收函數句柄（此函數在被選中為從接收時執行）
i2cSetSlaveReceiveHandler(i2cSlaveReceiveService);
//設置從發送函數句柄（此函數在被選中為從發送時執行）
i2cSetSlaveTransmitHandler(i2cSlaveTransmitService);
testI2cMemory();

}

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