2018年05月20日 | STM8S 模拟I2C程序

STM8S的硬件I2C还是存在问题,不敢贸然使用.

#define SCL PE_ODR_ODR1
#define SDA PE_ODR_ODR2
#define SDAM PE_IDR_IDR2
#define SET_SCL_OUT() {PE_DDR_DDR1=1; PE_CR1_C11 = 1; PE_CR2_C21 = 0;}
#define SET_SDA_OUT() {PE_DDR_DDR2=1; PE_CR1_C12 = 1; PE_CR2_C22 = 0;}
#define SET_SDA_IN() {PE_DDR_DDR2=0; PE_CR1_C12 = 0; PE_CR2_C22 = 0;}
//--------------------------------------------------------------
// Prototype : void I2C_Start(void)
// Calls : Delay_5us()
// Description : Start Singnal
//--------------------------------------------------------------
void I2C_Init(void)
{
I2C_CR1 &= 0xFE; // PE=0, disable I2C module 
SET_SCL_OUT();
SET_SDA_OUT(); 
}

//--------------------------------------------------------------
// Prototype : void Delay_5us(void)
// Description : 大约延时5us
//--------------------------------------------------------------
void Delay_5us(void)
{
uchar i; //fcpu 8MHz 时
for (i=50; i>0; i--);
}

//--------------------------------------------------------------
// Prototype : void I2C_Start(void)
// Calls : Delay_5us()
// Description : Start Singnal
//--------------------------------------------------------------
void I2C_Start(void)
{
// SDA 1->0 while SCL High
SDA = 1; 
SCL = 1; 
Delay_5us(); 
SDA = 0; 
Delay_5us(); 
SCL = 0; 
}

//--------------------------------------------------------------
// Prototype : void I2C_Stop(void)
// Calls : Delay_5us()
// Description : Stop Singnal
//-------------------------------------------------------------- 
void I2C_Stop(void)
{
// SDA 0->1 while SCL High
SDA = 0; 
SCL = 1; 
Delay_5us(); 
SDA = 1; 
Delay_5us(); 
}
//--------------------------------------------------------------
// Prototype : void I2C_SendACK(uchar ack);
// Calls : Delay_5us()
// Parameters : bit ack:1-noack, 0-ack
// Description : Master device send ACK to slave device.
//--------------------------------------------------------------
void I2C_SendACK(uchar ack)
{
if(ack == 0)
{
SDA = 0; 
} 
else
{
SDA = 1; 
}

SCL = 1; 
Delay_5us(); 

SCL = 0; 
Delay_5us(); 
}
//--------------------------------------------------------------
// Prototype : uchar I2C_SendByte(uchar sendDAT)
// Calls : Delay_5us()
// Parameters : uchar sendDAT---data to be send
// Return Value : CY--slave ack (1---noack，0---ack)
// Description : Send one byte to I2C
//--------------------------------------------------------------
uchar I2C_SendByte(uchar sendDAT)
{
uchar i,revack;
for (i= 0 ; i< 8; i++) 
{
SCL = 0; 
Delay_5us(); 
if (sendDAT & 0x80) // write data
{
SDA = 1;
}
else 
{
SDA = 0;
}
sendDAT <<= 1;
SCL = 1; 
Delay_5us(); 
} 

SCL = 0; 
Delay_5us(); 

SET_SDA_IN();

SCL = 1; 
asm("nop");
asm("nop");

revack = (uchar)SDAM;

Delay_5us(); 
SCL = 0; 

SET_SDA_OUT();

Delay_5us(); 
return revack;
}

//--------------------------------------------------------------
// Prototype : uchar I2C_RecvByte()
// Calls : Delay_5us()
// Parameters : none
// Return Value : revDAT- received data
// Description : Receive one byte from I2C
//--------------------------------------------------------------
uchar I2C_RecvByte()
{
uchar i;
uchar revDAT = 0;

SDA = 1; // latch the Data port befor reading

SET_SDA_IN();

for (i=0; i<8; i++) 
{ 
revDAT <<= 1;

SCL = 1; 

asm("nop");
asm("nop");

if (SDAM)
{
revDAT |= 0x01;
}
else
{
revDAT &= 0xfe;
}
Delay_5us(); 
SCL = 0; 
Delay_5us(); 
}

SET_SDA_OUT();

return revDAT;
}

//--------------------------------------------------------------
// Prototype : void Write_PT2314(uchar wdata)
// Calls : I2C_Start(), I2C_Stop(),I2C_SendByte()
// Parameters : RegAddr-- target memory address, 
// wrdata--- data to be writing
// Description : Write one byte to target memory
//--------------------------------------------------------------
void Write_24c02(uchar regadd,uchar wdata)
{
I2C_Start(); 
I2C_SendByte(0xA0); // Device Addr + Write (operation) 
I2C_SendByte(regadd); 
I2C_SendByte(wdata); 
I2C_Stop(); 
}
uchar Read_24c02(uchar regadd)
{
uchar revdata;

I2C_Start(); 
I2C_SendByte(0xA0); // Device Addr + Write (operation) 
I2C_SendByte(regadd); 

I2C_Start(); 
I2C_SendByte(0xA1); // Device Addr + Write (operation) 

revdata = I2C_RecvByte(); 
I2C_SendACK(1);

I2C_Stop(); 

return revdata;
}