十年專注單片機方案開發(fā)的方案公司英銳恩，分享PIC24F單片機之EEPROM讀寫中斷事件處理函數(shù)要點及說明。英銳恩現(xiàn)提供服務產(chǎn)品涉及主控芯片：8位單片機、16位單片機、32位單片機及各類運算放大器等。
/*-------------------------------------------------------------------------------------------------
PIC24F之EEPROM讀寫中斷事件處理函數(shù)要點及說明
注意: 這是一個通用的I2C/SMBUS通訊中斷處理程序
對于EEPROM來講，從機后面需要跟EEPROM需要讀寫的地址(I2CRegs.RWAddr)
對于SMBUS來說,從機后面需要跟SMBUS需要的命令(I2CRegs.RWAddr改為I2CRegs.CMD即可)
由于PIC24F的I2C不太標準,I2C1STAT被搞得很倒塌！??！一點都沒I2C的"大家閨秀"的樣子~~~
不過它的STOP還能激活中斷確實比LPCARM/AVR好一點點~~~
--------------------------------------------------------------------------------------------------*/
#include "i2c.h"
_PERSISTENT volatile I2CREGS I2CRegs;
_PERSISTENT volatile I2CBITS I2CBits;
void I2cInit(void)
{
unsigned int i;
TRIS_WP = PORTOUTMODE;//定義WP為輸出IO
TRIS_SCL1 = PORTOUTMODE;//定義SCL為輸出IO
TRIS_SDA1 = PORTINPUTMODE;//定義SDA為輸出入IO
ODC_SCL1 = 1;//OC輸出
ODC_SDA1 = 1;//OC輸出
WP = 1;//寫保護
I2CRegs.MaxCount = 0x200;//8KByte
I2CRegs.I2CAddr = 0xa0;//器件地址
I2CRegs.RWAddr = 0;//EEPROM讀寫地址
I2CRegs.TxCount = 0;//發(fā)送數(shù)據(jù)字節(jié)個數(shù)
I2CRegs.RxCount = 0;//接收數(shù)據(jù)字節(jié)個數(shù)
for (i = 0; i < 16; i ++)
{
I2CRegs.TxBuffer[i] = 0;//發(fā)送緩沖區(qū)清零
}
for (i = 0; i < 256; i ++)
{
I2CRegs.RxBuffer[i] = 0;//接收緩沖區(qū)清零
}
I2C1CON = 0;
// I2C1CONbits.A10M = 0;//7位地址模式
I2C1CONbits.SCLREL = 1;
I2C1MSK = 0;
I2C1STAT = 0;
_MI2C1IF = 0;
_SI2C1IF = 0;
I2C1BRG = (FCY / (2 * I2CBAUD)) - 1;//波特率計算
/*------------------------------------------------------------------------
定義I2C串口2中斷優(yōu)先級位1111)
-------------------------------------------------------------------------*/
IPC4bits.MI2C1P0 = 1;
IPC4bits.MI2C1P1 = 1;
IPC4bits.MI2C1P2 = 1;
I2C1CONbits.I2CEN = 1;//允許I2C功能
_MI2C1IE = 1;//允許主設備中斷
// I2cStop();
}
/*------------------------------------------------------------------
EEPROM讀塊函數(shù)(只能在回調(diào)函數(shù)I2CReadCallBack中得到讀出的數(shù)據(jù))
-------------------------------------------------------------------*/
void I2CReadBuffers(unsigned int E2RomAddr, unsigned int ReadSize)
{
if (ReadSize && (ReadSize <= 256))
{
I2CRegs.TxCount = 0;
I2CRegs.RxCount = ReadSize;
I2CRegs.RWAddr = E2RomAddr;
I2CRegs.I2CAddr |= 1;//0xa1
I2cStart();
}
}
void I2CReadByte(unsigned int E2RomAddr)
{
I2CRegs.TxCount = 0;
I2CRegs.RxCount = 1;
I2CRegs.RWAddr = E2RomAddr;
I2CRegs.I2CAddr |= 1;//0xa1
I2cStart();
}
/*------------------------------------------------------------------
EEPROM寫塊函數(shù)
-------------------------------------------------------------------*/
void I2CWriteBuffers(unsigned int E2RomAddr, unsigned int WriteSize)
{
if (WriteSize && (WriteSize <= 16))
{
I2CRegs.TxCount = WriteSize;
I2CRegs.RxCount = 0;
I2CRegs.RWAddr = E2RomAddr;
I2CRegs.I2CAddr &= 0xfe;//0xa0
I2cStart();
}
}
void I2CWriteByte(unsigned int E2RomAddr, unsigned char cData)
{
I2CRegs.TxBuffer[0] = cData;
I2CRegs.TxCount = 1;
I2CRegs.RxCount = 0;
I2CRegs.RWAddr = E2RomAddr;
I2CRegs.I2CAddr &= 0xfe;//0xa0
I2cStart();
}
/*------------------------------------------------------------------
用戶讀回調(diào)函數(shù)
-------------------------------------------------------------------*/
void I2CReadCallBack(void)
{
if ((I2CRegs.RWAddr + I2CRegs.RxCount) <= I2CRegs.MaxCount)
{
// I2CRegs.RWAddr += I2CRegs.RxCount;
// I2CReadBuffers(I2CRegs.RWAddr, I2CRegs.RxCount);//繼續(xù)讀
}
}
/*------------------------------------------------------------------
用戶寫回調(diào)函數(shù)
-------------------------------------------------------------------*/
void I2CWriteCallBack(void)
{
if ((I2CRegs.RWAddr + I2CRegs.TxCount) <= I2CRegs.MaxCount)
{
// I2CRegs.RWAddr += I2CRegs.TxCount;
// I2CWriteBuffers(I2CRegs.RWAddr, I2CRegs.TxCount);//繼續(xù)寫
}
}
/*-----------------------------------------------------------------
EEPROM讀寫啟動函數(shù)
-------------------------------------------------------------------*/
void I2cStart(void)
{
/*------------------------------------------------------------------------
//本程序在狀態(tài)I2C_MT_ADDRL_ACK下進行瞬間打開,也可在此打開，不過安全不好
if (I2CRegs.TxCount)//需要寫入字節(jié)
{
WP = 0;//不寫保護
}
else
{
WP = 1;//寫保護
}
--------------------------------------------------------------------------*/
I2C1STATbits.IWCOL = 0;
I2CBits.BusyFlag = 1;
I2CRegs.State = I2C_START;//主機準備發(fā)送啟始位
I2CRegs.Count = 0;//發(fā)送數(shù)據(jù)個數(shù)
I2CBits.I2CFlag = 0;
I2C1CONbits.SEN = 1;//發(fā)送Start信號
}
/*------------------------------------------------------------------
/*------------------------------------------------------------------
EEPROM讀寫錯誤退出函數(shù)
-------------------------------------------------------------------*/
void I2cExit(void)
{
I2C1STATbits.IWCOL = 0;
I2CBits.BusyFlag = 0;
I2CRegs.State = I2C_FAILED;
I2C1CONbits.PEN = 1;//發(fā)送Stop信號
WP = 1;//寫保護
}
/*------------------------------------------------------------------
EEPROM讀寫中斷事件處理函數(shù)(說明見文件頭部)
-------------------------------------------------------------------*/
void I2CExec(void)
{
if (I2C1STATbits.S)//收到Start過信號
{
switch (I2CRegs.State)
{
case I2C_START://收到Start信號
I2C1TRN = I2CRegs.I2CAddr & 0xfe;//發(fā)送器件寫地址(通知從機只能聽)
I2CRegs.State = I2C_MT_SLA_ACK;//下次應該接收器件寫地址應答信號
break;
case I2C_MT_SLA_ACK://收到器件寫地址應答信號
if (!I2C1STATbits.ACKSTAT)//收到Ack信號
{
if (I2CRegs.MaxCount > 0x100)//EEPROM容量超過256個字節(jié),EEPROM地址需要兩次發(fā)送
{
I2C1TRN = I2CRegs.RWAddr >> 8;//發(fā)送EEPROM寫高8位地址
I2CRegs.State = I2C_MT_ADDRH_ACK;//下次應該接收EEPROM寫高8位地址應答信號
}
else//小容量只需一次發(fā)送!!!
{
I2C1TRN = I2CRegs.RWAddr;//發(fā)送EEPROM寫低8位地址
I2CRegs.State = I2C_MT_ADDRL_ACK;//下次應該接收EEPROM寫低8位地址應答信號
I2CRegs.Count = 0;//清空發(fā)送緩沖計數(shù)器
}
}
else//收到NAck信號
{
I2cExit();//錯誤的ACK信號
}
break;
case I2C_MT_ADDRH_ACK://收到EEPROM寫高8位地址應答信號
if (!I2C1STATbits.ACKSTAT)//收到Ack信號
{
I2C1TRN = I2CRegs.RWAddr & 0xff;//發(fā)送EEPROM寫低8位地址
I2CRegs.State = I2C_MT_ADDRL_ACK;//下次應該接收EEPROM寫低8位地址應答信號
I2CRegs.Count = 0;//清空發(fā)送緩沖計數(shù)器
}
else//收到NAck信號
{
I2cExit();//錯誤的ACK信號
}
break;
case I2C_MT_ADDRL_ACK://收到EEPROM寫高低8位地址應答信號
if (I2CRegs.TxCount)//寫保護只在寫入期間不保護，增加了對誤寫入的安全防護能力!!!
{
WP = 0;//不寫保護
}
case I2C_MT_DATA_ACK://收到應答信號
if (!I2C1STATbits.ACKSTAT)//收到Ack信號
{
if (I2CRegs.Count < I2CRegs.TxCount)//緩沖區(qū)未空
{
I2C1TRN = I2CRegs.TxBuffer[I2CRegs.Count ++];//繼續(xù)發(fā)送數(shù)據(jù)
}
else if (I2CRegs.Count == I2CRegs.TxCount)//緩沖區(qū)已空
{
if (I2CRegs.I2CAddr & 1)//應該開始接收數(shù)據(jù)
{
I2cReStart();//發(fā)送重復位命令
}
else//只寫退出
{
I2cStop();//正常發(fā)送結(jié)束
}
}
else//干擾出錯
{
I2cExit();//錯誤
}
}
else//收到NAck信號(可能被寫保護)
{
I2cExit();//錯誤的ACK信號
}
break;
case I2C_REP_START://收到ReStart信號
I2C1TRN = I2CRegs.I2CAddr | I2C_READ;//發(fā)送器件讀地址(通知從機可以說話)
I2CRegs.State = I2C_MR_SLA_ACK;//下次應該接收器件寫讀地址應答信號
break;
case I2C_MR_SLA_ACK://收到器件讀地址應答信號
if (!I2C1STATbits.ACKSTAT)//收到Ack
信號
{
I2C1CONbits.RCEN = 1;//開始接收數(shù)據(jù)
I2CRegs.State = I2C_MR_DATA;//下次應該收接收數(shù)據(jù)
}
else//收到NAck信號
{
I2cExit();//錯誤的ACK信號
}
break;
case I2C_MR_DATA://收到接收數(shù)據(jù)
if (I2CRegs.Count < I2CRegs.RxCount)
{
// I2C1STATbits.I2COV = 0;
I2CRegs.RxBuffer[I2CRegs.Count ++] = I2C1RCV;
if (I2CRegs.Count < I2CRegs.RxCount)
{
I2C1CONbits.ACKDT = 0;//應答子機
I2CRegs.State = I2C_MR_DATA_EN;//下次應該收到器件允許繼續(xù)讀信號
}
else
{
I2C1CONbits.ACKDT = 1;//非應答子機
I2CRegs.State = I2C_MR_DATA_STOP;//下次應該收到退出信號
}
I2C1CONbits.ACKEN = 1;//向從機發(fā)送(非)應答信號
}
else//正確的狀態(tài)已分支到I2C_MR_DATA_STOP
{
I2cExit();//錯誤
}
break;
case I2C_MR_DATA_EN://收到器件允許繼續(xù)讀信號
I2C1CONbits.RCEN = 1;//開始接收數(shù)據(jù)
I2CRegs.State = I2C_MR_DATA;//下次應該繼續(xù)接收數(shù)據(jù)
break;
case I2C_MR_DATA_STOP://收到器件退出信號
I2cStop();//正常接收結(jié)束
break;
default://其他不可預料的錯誤
I2cExit();//錯誤
}
}
else if (I2C1STATbits.P)//收到Stop信號
{
if (I2CRegs.State == I2C_SUCCEEDED)//成功,回調(diào)
{
if (I2CRegs.I2CAddr & 1)//讀
{
I2CBits.ReadFlag = 1;//激活用戶讀回調(diào)函數(shù)I2CReadCallBack()
}
else//寫
{
I2CBits.WriteFlag = 1;//激活用戶寫回調(diào)函數(shù)I2CWriteCallBack()
}
}
}
else//無法確認的復雜錯誤
{
I2cExit();//錯誤出錯退出
}
}
（文源網(wǎng)絡，侵刪）
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