i2c.c

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#include <c8051f020.h>					// SFR declarations

//------------------------------------------------------------------------------------
// Global CONSTANTS
//------------------------------------------------------------------------------------

#define 	WRITE	0x00						// SMBus WRITE command
#define		READ 	0x01						// SMBus READ command

// Device addresses (7 bits, lsb is a don't care)
#define		CLOCK3530_ADDRESS_RESET		0x60		//1 ack
#define		CLOCK3530_ADDRESS_STATUS	0x62		//2 ack
#define		CLOCK3530_ADDRESS_DATEHOUR	0x64		//8 ack  year month day week hour minute second
#define		CLOCK3530_ADDRESS_HOUR		0x66		//4 ack  hour minute second
#define		CLOCK3530_ADDRESS_INT1		0x68		//3 ack  
#define		CLOCK3530_ADDRESS_INT2		0x6A		//3 ack  

union 
{
unsigned char ClockString[7];
struct RealClock
	{
		unsigned char Year,Month,Day,Week,Hour,Minute,Second;
	} RT;
} RealTime;


// SMBus states:
// MT = Master Transmitter
// MR = Master Receiver
#define	SMB_BUS_ERROR	0x00			// (all modes) BUS ERROR
#define	SMB_START		0x08			// (MT & MR) START transmitted
#define	SMB_RP_START	0x10			// (MT & MR) repeated START
#define	SMB_MTADDACK	0x18			// (MT) Slave address + W transmitted;
										//  ACK received
#define	SMB_MTADDNACK	0x20			// (MT) Slave address + W transmitted;
										//  NACK received
#define	SMB_MTDBACK		0x28			// (MT) data byte transmitted; ACK rec'vd
#define	SMB_MTDBNACK	0x30			// (MT) data byte transmitted; NACK rec'vd
#define	SMB_MTARBLOST	0x38			// (MT) arbitration lost
#define	SMB_MRADDACK	0x40			// (MR) Slave address + R transmitted;
										//  ACK received
#define	SMB_MRADDNACK	0x48			// (MR) Slave address + R transmitted;
										//  NACK received
#define	SMB_MRDBACK		0x50			// (MR) data byte rec'vd; ACK transmitted
#define	SMB_MRDBNACK	0x58			// (MR) data byte rec'vd; NACK transmitted


//-----------------------------------------------------------------------------------
//Global VARIABLES
//-----------------------------------------------------------------------------------
char COMMAND;			// Holds the slave address + R/W bit for use in the SMBus ISR.

unsigned char *I2CDataBuff;						

char BYTE_NUMBER;							// Used by ISR to check what data has just been
												// sent - High address byte, Low byte, or data byte

unsigned char HIGH_ADD, LOW_ADD;		// High & Low byte for EEPROM memory address
				
bit SM_BUSY;								// This bit is set when a send or receive
												// is started. It is cleared by the
												// ISR when the operation is finished.


//------------------------------------------------------------------------------------
// Function PROTOTYPES
//------------------------------------------------------------------------------------

void SMBus_ISR (void);								

//------------------------------------------------------------------------------------
// MAIN Routine
//------------------------------------------------------------------------------------
//
// Main routine configures the crossbar and SMBus, and tests
// the SMBus interface between the three EEPROMs


void ResetRealClock(void)
{
	while (SM_BUSY);									// Wait for SMBus to be free.
	SM_BUSY = 1;										// Occupy SMBus (set to busy)
	SMB0CN = 0x44;										// SMBus enabled, ACK on acknowledge cycle
	BYTE_NUMBER = 0;									// 2 address bytes.
	COMMAND = (CLOCK3530_ADDRESS_RESET | READ);		// Chip select + READ
	STA = 1;											// Start transfer
	while (SM_BUSY);									// Wait for transfer to finish
}

//======================写S-3530A内部实时数据寄存器程序=====================
//功能：将设定年、月、日、星期、时、分、秒数据写入S-3530A                  |
//入口：发送数据放在年、月、日、星期、时、分、秒各寄存器                   |
//出口：NONE                                                               |
//==========================================================================
void SetRealClock(void)
{
	while (SM_BUSY);									// Wait for SMBus to be free.
	SM_BUSY = 1;										// Occupy SMBus (set to busy)
	SMB0CN = 0x44;										// SMBus enabled, ACK on acknowledge cycle
	BYTE_NUMBER = 7;									// 2 address bytes.
	COMMAND = (CLOCK3530_ADDRESS_DATEHOUR | WRITE);		// Chip select + WRITE
	I2CDataBuff = &RealTime.ClockString[0];				// Data to be writen
	STA = 1;
	while (SM_BUSY);											// Start transfer
}

//==================读S-3530A实时数据寄存器子程序===========================
//功能：从S-3530A读入当前时间数据                                          |
//入口：NONE                                                               |
//出口：接收数据放在年、月、日、星期、时、分、秒各寄存器                   |
//==========================================================================
void GetRealClock(void)
{
	while (SM_BUSY);									// Wait for SMBus to be free.
	SM_BUSY = 1;										// Occupy SMBus (set to busy)
	SMB0CN = 0x44;										// SMBus enabled, ACK on acknowledge cycle
	BYTE_NUMBER = 7;									// 2 address bytes.
	COMMAND = (CLOCK3530_ADDRESS_DATEHOUR | READ);		// Chip select + READ
	I2CDataBuff = &RealTime.ClockString[0];				// Data to be writen
	STA = 1;											// Start transfer
	while (SM_BUSY);									// Wait for transfer to finish
}

//============================写状态寄存器程序==============================
//功能：读/写S-3530A状态寄存器，对S-3530A进行设置                          |
//入口：NONE           出口：NONE                                          |
//==========================================================================
unsigned char  GetRealClockStatus(void)
{
	unsigned char result; 
	while (SM_BUSY);									// Wait for SMBus to be free.
	SM_BUSY = 1;										// Occupy SMBus (set to busy)
	SMB0CN = 0x44;										// SMBus enabled, ACK on acknowledge cycle
	BYTE_NUMBER = 1;									
	COMMAND = (CLOCK3530_ADDRESS_STATUS | READ);		
	I2CDataBuff = &result;								
	STA = 1;											// Start transfer
	while (SM_BUSY);									// Wait for transfer to finish
	return result;
}
void SetRealClockStatus(unsigned char status)
{
	while (SM_BUSY);									// Wait for SMBus to be free.
	SM_BUSY = 1;										// Occupy SMBus (set to busy)
	SMB0CN = 0x44;										// SMBus enabled, ACK on acknowledge cycle
	BYTE_NUMBER = 1;									
	COMMAND = (CLOCK3530_ADDRESS_STATUS | WRITE);		
	I2CDataBuff = &status;								
	STA = 1;											// Start transfer
}
/*
void  SetRealClockINT1(unsigned int Int1)
{
	while (SM_BUSY);									// Wait for SMBus to be free.
	SM_BUSY = 1;										// Occupy SMBus (set to busy)
	SMB0CN = 0x44;										// SMBus enabled, ACK on acknowledge cycle
	BYTE_NUMBER = 2;									
	COMMAND = (CLOCK3530_ADDRESS_INT1 | WRITE);		
	I2CDataBuff = (unsigned char*)&Int1;								
	STA = 1;											// Start transfer
}
*/
#include "INTRINS.H"

unsigned char revolve(unsigned char val)
{
char i;
unsigned char val1=0;
	for (i=0;i<8;i++)
	{
		if (val&0x1)
			val1++;
		val1=_crol_(val1,1);
		val=_cror_(val,1);
	}
	val1=_cror_(val1,1);
	return val1;
}

void TestI2C (void)
{
unsigned char var ;
	WDTCN = 0xde;									// disable watchdog timer
	WDTCN = 0xad;
	
	OSCICN |= 0x03;								// Set internal oscillator to highest setting
														// (16 MHz)

	XBR0 |= 0x07;									// Route SMBus to GPIO pins through crossbar
	XBR2 |= 0x44;									// Enable crossbar and weak pull-ups

    P0MDOUT |= 0x1D; 
    P1MDOUT |= 0x01; 
	
	SMB0CN = 0x44;									// Enable SMBus with ACKs on acknowledge cycle
	SMB0CR = -80;									// SMBus clock rate = 100kHz.

	EIE1 |= 2;										// SMBus interrupt enable
	EA = 1;											// Global interrupt enable

	SM_BUSY = 0;									// Free SMBus for first transfer.

//	SetRealClockINT1(0x8000);
	var = GetRealClockStatus();
	ResetRealClock();
	var = GetRealClockStatus();
	SetRealClockStatus(0x82);
	var = GetRealClockStatus();
	RealTime.RT.Year=0x02;	
	RealTime.RT.Month=0x06;	
	RealTime.RT.Day=0x05;	
	RealTime.RT.Week=0x02;	
	RealTime.RT.Hour=0x11;	
	RealTime.RT.Minute=0x14;	
	RealTime.RT.Second=0x45;	
	SetRealClock();
	RealTime.RT.Year=0x0;	
	RealTime.RT.Month=0x0;	
	RealTime.RT.Day=0x0;	
	RealTime.RT.Week=0x0;	
	RealTime.RT.Hour=0x0;	
	RealTime.RT.Minute=0x0;	
	RealTime.RT.Second=0x0;	
	GetRealClock();
/*	RealTime.RT.Year=0x02;	
	RealTime.RT.Month=0x06;	
	RealTime.RT.Day=0x05;	
	RealTime.RT.Week=0x02;	
	RealTime.RT.Hour=0x11;	
	RealTime.RT.Minute=0x14;	
	RealTime.RT.Second=0x45;	
*/	SetRealClock();
	GetRealClock();
	GetRealClock();
	GetRealClock();
	GetRealClock();
}


//------------------------------------------------------------------------------------
// Interrupt Service Routine
//------------------------------------------------------------------------------------
void SMBUS_ISR (void) interrupt 7
{
	switch (SMB0STA)
		{ 	// SMBus 状态码SMB0STA 寄存器
			// 主发送器/接收器起始条件已发送
		case SMB_START:
			SMB0DAT = COMMAND ; // 装入要访问的从器件的地址
			STA = 0; 			// 手动清除START 位
			break;
			//主发送器/接收器重复起始条件已发送
			// 该状态只应在读操作期间出现在存储器地址已发送并得到确认之后 ?
		case SMB_RP_START:
			SMB0DAT = COMMAND; // COMMAND 中应保持从地址 + R.
			STA = 0;
			break;
			// 主发送器从地址 + WRITE 已发送收到ACK
		case SMB_MTADDACK:
			// 主发送器数据字节已发送收到ACK
		case SMB_MTDBACK:
			if (BYTE_NUMBER)
			{
					SMB0DAT = revolve(*I2CDataBuff);					// If R/W=WRITE, load byte to write.
					I2CDataBuff++;
					BYTE_NUMBER--;			
			}
			else
			{
				STO = 1;	SM_BUSY = 0;						// Free SMBus
			}
			break;
			// 主发送器从地址 + WRITE 已发送收到NACK
			// 从器件不应答发送STOP + START 重试
		case SMB_MTADDNACK:
			STO = 1;			STA = 1;
		break;
			// 主发送器数据字节已发送收到NACK
			// 从器件不应答发送STOP + START 重试
		case SMB_MTDBNACK:
			STO = 1;			STA = 1;
		break;
			// 主发送器竞争失败
			// 不应出现如果出现重新开始传输过程
		case SMB_MTARBLOST:
			STO = 1;			STA = 1;
		break;

			// 主接收器从地址 + READ 已发送,收到ACK
		case SMB_MRADDACK:
			AA = 1; // 在应答周期ACK
			if (!BYTE_NUMBER)
			{	
				STO = 1;	SM_BUSY = 0; // 释放SMBus
			}
		break;
			// 主接收器从地址 + READ 已发送收到NACK
			// 从器件不应答发送重复起始条件重试
		case SMB_MRADDNACK:
			STA = 1;
		break;
			// 收到数据字节ACK 已发送
			// 该状态不应出现因为AA 已在前一状态被清0 如果出现发送停止条件
		case SMB_MRDBACK:
			if (BYTE_NUMBER)
			{
				*I2CDataBuff=revolve(SMB0DAT);		
				I2CDataBuff++;
				BYTE_NUMBER--;			
			}
			if (!BYTE_NUMBER)	AA= 0;
		break;
			// 收到数据字节NACK 已发送
			// 读操作已完成读数据寄存器后发送停止条件
		case SMB_MRDBNACK:
			STO = 1;
			SM_BUSY = 0; // 释放SMBus
		break;
			// 在本应用中所有其它状态码没有意义通信复位
		default:
			STO = 1; // 通信复位
			SM_BUSY = 0; 
		break;
		}
	SI=0; // 清除中断标志
}
/*
{
	switch (SMB0STA){			// Status code for the SMBus (SMB0STA register)
		case SMB_START:					
			SMB0DAT = COMMAND;					// COMMAND should hold slave address + R.
			break;
		case SMB_MTADDNACK:
			STO = 1;
			STA = 1;
			break;
		case SMB_RP_START:
//			SMB0DAT = COMMAND;					// COMMAND should hold slave address + R.
//			STA = 0;											
//			break;
		case SMB_MTADDACK:
		case SMB_MTDBACK:
			if (BYTE_NUMBER)
			{
					if (COMMAND & 0x01)					// If R/W=READ, 
					{
						STA = 1;
					}
					else
					{
						SMB0DAT = *I2CDataBuff;					// If R/W=WRITE, load byte to write.
						I2CDataBuff++;
						BYTE_NUMBER--;			
					}
			}
			else
			{
				STO = 1;
				SM_BUSY = 0;						// Free SMBus
			}
			break;
		
		// Master Transmitter: Data byte transmitted.  NACK received.
		// Slave not responding.  Send STOP followed by START to try again.
		case SMB_MTDBNACK:
			STO = 1;
			STA = 1;
			break;
		
		// Master Transmitter: Arbitration lost.
		// Should not occur.  If so, restart transfer.
		case SMB_MTARBLOST:
			STO = 1;
			STA = 1;
			break;

		// Master Receiver: Slave address + READ transmitted.  NACK received.
		// Slave not responding.  Send repeated start to try again.
		case SMB_MRADDNACK:
			STA = 1;
			break;

		// Data byte received.  ACK transmitted.
		// State should not occur because AA is set to zero in previous state.
		// Send STOP if state does occur.
		case SMB_MRDBACK:
			STO = 1;
			SM_BUSY = 0;
			break;

		// Master Receiver: Slave address + READ transmitted.  ACK received.
		// Set to transmit NACK after next transfer since it will be the last (only) byte.
		case SMB_MRADDACK:
//			AA = 0;										// NACK sent on acknowledge cycle.
//			break;

		// Data byte received.  NACK transmitted.
		// Read operation has completed.  Read data register and send STOP.
		case SMB_MRDBNACK:
			if (BYTE_NUMBER)
			{
					if (COMMAND & 0x01)					// If R/W=READ, 
					{
						*I2CDataBuff=SMB0DAT;		
						I2CDataBuff++;
					}
					BYTE_NUMBER--;			
			}
			else
			{
				STO = 1;
				SM_BUSY = 0;						// Free SMBus
			}
			break;
		// All other status codes meaningless in this application. Reset communication.
		default:
			STO = 1;										// Reset communication.
			SM_BUSY = 0;
			break;
		}
	
	SI=0;													// clear interrupt flag
}
*/