/*************************************************************************
Send one byte to I2C device
Input: byte to be transfered
Return: 0 write successful
1 write failed
*************************************************************************/
unsigned char lib_i2c_write(unsigned char data)
{
int i = 8;
// transmit byte
while (i--) {
SCL_L;
I2C_delay();
if (data & 0x80)
SDA_H;
else
SDA_L;
data <<= 1;
I2C_delay();
SCL_H;
I2C_delay();
}
SCL_L;
if (lib_i2c_waitack()) {
lib_i2c_stop();
return 1;
}
return 0;
}
uint8_t I2C_gen_start(void) {
// Release SCL
I2C_PORT |= (1<<I2C_SCL);
while(!(I2C_PORT & (1<<I2C_SCL))) ;
#ifdef I2C_FAST_MODE
I2C_delay(I2C_T2);
#else
I2C_delay(I2C_T1);
#endif
// Generate start condition
I2C_PORT &= ~(1<<I2C_SDA);
I2C_delay(I2C_T2);
I2C_PORT &= ~(1<<I2C_SCL);
I2C_PORT |= (1<<I2C_SDA);
#ifdef SIGNAL_VERIFY
// Check that the start condition was detected
if (!(USISR & (1<<USISIF))) {
I2C_state.errorState = I2C_ERR_MISSING_START_CON;
return FALSE;
}
#endif
return TRUE;
}
BUS_Status I2C_Start(void)
{
//before: SCL=H SDA=H,means bus is free
SDA_H; //1
SCL_H; //2
I2C_delay(); //3
if(!(SDA_read))
{
ERROR_MACRO(IIC_DEV,I2C_Start_ERROR_BUS_BUSY);
return BUS_BUSY;
}
SDA_L; //4
I2C_delay(); //5
// SDA_L; //6
// I2C_delay(); //7
if(SDA_read)
{
ERROR_MACRO(IIC_DEV,I2C_Start_ERROR_BUS_ERROR);
return BUS_ERROR;
}
SCL_L;
//After: SCL=L SDA=L
return BUS_READY;
}
//////////////////////////////////////////////////////////////////////
// Returns 0 for no errors = the ACK bit from the slave
unsigned short I2C_Wr(unsigned short data) {
unsigned short ret=0,i;
// grab the data
for(i = 0; i < 8; i++) {
I2C_SCL_0; // Clock low
if (data & 0x80) I2C_SDA_1; else I2C_SDA_0; // Data output
data <<= 1; // Next data bit.
I2C_delay(); // low T/2.
I2C_SCL_1; // Clock released to high.
I2C_delay(); // high T/2.
}
// get ACK or NACK
I2C_SCL_0;
I2C_SDA_1; // Release the data line
SET_PIN_INPUT(I2C_SDA_PIN);
I2C_delay(); // low T/2.
I2C_SCL_1;
// Sample the ACK
ret = I2C_SDA_IN;
I2C_delay(); // high T/2.
I2C_SCL_0; // Return clock to safe state
SET_PIN_OUTPUT(I2C_SDA_PIN);
return ret;
}
BUS_ACK_Status I2C_WaitAck(void)
{
//等待ACK应该是在发送完数据之后,所以之前:
// SCL=H SDA=DATA
unsigned char ucErrTime=0;
//SDA_H;SDA_H;SDA_H;I2C_delay(); //初始化数据是NACK,不能拉低!
SCL_L; //假设你是从机->SCL=L时更新数据,SDA=H时数据是保持的
I2C_delay(); //保持一下
//while(1);
SCL_H; //此时拉高SCL,于是从机的数据应该是保持的
I2C_delay(); //等待数据就位
while(SDA_read)//读到H->NACK,适当等待
{
ucErrTime++;
if(ucErrTime>=50)//一小段时间后还是NACK->是NACK
{
//ERROR_MACRO(IIC_DEV,I2C_ERROR_BUS_NACK);
printf("NoACK\r\n");
//此时SCL=H SDA =H,直接STOP
I2C_Stop();
return BUS_NACK;
}
}
SCL_L; //拉低SCL,保持总线BUSY
SDA_H; //更具I2C协议P10SDA应该在SCL变为L之后拉高
I2C_delay();
//SCL=L SDA=ACK/NACK
return BUS_ACK;
}
unsigned char I2C_ReceiveByte(void) //数据从高位到低位//
{
unsigned char i=8;
unsigned char ReceiveByte=0x00;
while(i--)
{
ReceiveByte<<=1;
SCL_L;I2C_delay();
SCL_H;//给出一个上升沿,使设备输出SDA数据
I2C_delay();//保证数据从设备中输出了
if(SDA_read)
{
ReceiveByte|=0x01;
}
I2C_delay();
}
SCL_L;
//SDA_L;
//I2/C_delay();I2C_delay();I2C_delay();I2C_delay();
//I2C_delay();I2C_delay();I2C_delay();I2C_delay();
return ReceiveByte;
}
// Run the shift register until the counter overflows
// Function resets SDA line to output on return
uint8_t I2C_byte_xfer(uint8_t reg) {
// Preset counter
USISR = reg;
// Setup control register for clock strobe
reg = (1<<USIWM1) | (1<<USICS1) | (1<<USICLK) | (1<<USITC);
do {
I2C_delay(I2C_T1);
// Positive edge
USICR = reg;
// Wait for clock stretching
while (!(I2C_PIN & (1<<I2C_SCL))) ;
I2C_delay(I2C_T2);
// Negative edge
USICR = reg;
} while (!(USISR & (1<<USIOIF)));
I2C_delay(I2C_T1);
// Save shift register
reg = USIDR;
// Release SDA
USIDR = 0xFF;
// Set SDA as output
I2C_DDR |= (1<<I2C_SDA);
return reg;
}
//不产生ACK应答
static void IIC_NAck(void)
{
SDA_OUT();
IIC_SDA(1);
IIC_SCL(1);
I2C_delay();
IIC_SCL(0);
I2C_delay();
}
//产生IIC停止信号
static void IIC_Stop(void)
{
SDA_OUT();//sda线输出
IIC_SDA(0);//STOP:when CLK is high DATA change form low to high
IIC_SCL(1);
I2C_delay();
IIC_SDA(1);//发送I2C总线结束信号
I2C_delay();
}
/*******************************************************************************
* Function Name : I2C_Stop
* Description : None
* Input : None
* Output : None
* Return : None
* Attention : None
*******************************************************************************/
static void I2C_Stop(void)
{
SDA_L;
I2C_delay();
SCL_H;
I2C_delay();
SDA_H;
I2C_delay();
}
/*************************************************************************
Terminates the data transfer and releases the I2C bus
*************************************************************************/
void lib_i2c_stop(void)
{
SCL_L;
I2C_delay();
SDA_L;
I2C_delay();
SCL_H;
I2C_delay();
SDA_H;
I2C_delay();
}
/**************************************
* I2Cstop:keep SCL high, SDA low to high
* ________________
* SCL:
* ______
* SDA: ________/
* 函数返回时:SDA,SCL均为高电平
***************************************/
void I2C_Stop(void)
{
SCL_L;
I2C_delay();
SDA_L;
I2C_delay();
SCL_H;
I2C_delay();
SDA_H;
}
void I2C_ACK()
{
SCL_L;
I2C_delay();
SDA_L;
I2C_delay();
SCL_H;
I2C_delay();
SCL_L;
I2C_delay();
}
void I2C_STOP()
{
SCL_L;
I2C_delay();
SDA_L;
I2C_delay();
SCL_H;
I2C_delay();
SDA_H;
I2C_delay();
}
unsigned char i2c_read_bit(void) {
unsigned char bit;
read_SDA();
I2C_delay();
while (read_SCL() == 0); // Clock stretching
bit = read_SDA();
I2C_delay();
clear_SCL();
I2C_delay();
return bit;
}
/*******************************************************************************
* Function Name : I2C_NoAck
* Description : Master Send No Acknowledge Single
* Input : None
* Output : None
* Return : None
****************************************************************************** */
void I2C_NoAck(void)
{
SCL_L;
I2C_delay();
SDA_H;
I2C_delay();
SCL_H;
I2C_delay();
SCL_L;
I2C_delay();
}
/*
*=========================================================
* 函数功能：IIC总线初始化信号
* 参数：无
* 函数返回值：无
* SDA ---
* |________
* SCL ----------
* |____
*=========================================================
*/
void I2C_Start(void)
{
SCL_L;
I2C_delay();
SDA_H;
I2C_delay();
SCL_H;
I2C_delay();
SDA_L;
I2C_delay();
}
/*******************************************************************************
* Function Name : I2C_Ack
* Description : None
* Input : None
* Output : None
* Return : None
* Attention : None
*******************************************************************************/
static void I2C_Ack(void)
{
SCL_L;
I2C_delay();
SDA_L;
I2C_delay();
SCL_H;
I2C_delay();
SCL_L;
I2C_delay();
}
//产生IIC起始信号
static bool IIC_Start(void)
{
SDA_OUT(); //sda线输出
IIC_SDA(1);
IIC_SCL(1);
I2C_delay();
IIC_SDA(0);//START:when CLK is high,DATA change form high to low
I2C_delay();
IIC_SCL(0);//钳住I2C总线，准备发送或接收数据
return TRUE ;
}
void i2c_stop(void) {
// set SDA to 0
clear_SDA();
I2C_delay();
while (read_SCL() == 0); // Clock stretching
I2C_delay();
if (read_SDA() == 0) {
arbitration_lost();
}
I2C_delay();
started = 0;
}
/*******************************************************************************
* Function Name : I2C_Start
* Description : None
* Input : None
* Output : None
* Return : None
* Attention : None
*******************************************************************************/
static int I2C_Start(void)
{
SDA_H;
I2C_delay();
SCL_H;
I2C_delay();
SDA_L;
I2C_delay();
SCL_L;
I2C_delay();
return ENABLE;
}
//////////////////////////////////////////////////////////////////////
// Stop command
//
// SDA 0-0-1
// SCL 0-1-1
//
void I2C_Stop(void) {
I2C_SCL_0; // Force to zero as can be sent at any time.
I2C_SDA_0; // Clock 1st so do not make a command.
I2C_delay();
I2C_SCL_1;
I2C_delay();
I2C_SDA_1;
I2C_delay();
}
//////////////////////////////////////////////////////////////////////
// Start command
//
// SDA 1-0-0
// SCL 1-1-0
//
// Asumptions : coming from bus free state (d=1,ck=1)
void I2C_Start(void) {
I2C_SDA_1;
I2C_SCL_1;
I2C_delay();
I2C_SDA_0;
I2C_delay();
I2C_SCL_0;
I2C_delay();
}
/*******************************************************************************
* Function Name : I2C_Start
* Description : Master Start Simulation IIC Communication
* Input : None
* Output : None
* Return : Wheather Start
****************************************************************************** */
uint8_t I2C_Start(void)
{
SDA_H;
SCL_H;
I2C_delay();
if(!SDA_read)return 0; //SDA线为低电平则总线忙,退出
SDA_L;
I2C_delay();
if(SDA_read) return 0; //SDA线为高电平则总线出错,退出
SDA_L;
I2C_delay();
return 1;
}
void I2C_NAck(void)
{
SCL_L; //1 首先拉低SCL,开始准备数据
SDA_H; //2 在SCL为低电平是准备数据(ACK=1)
I2C_delay(); //3 保持一下
SCL_H; //4 SCL拉高,进行采样
I2C_delay(); //5 保持SCL=1的时间->Note:确保采样时间
SCL_L; //复位SCL->L完成一个clock
//结束时,SCL=L SDA=NACK
}
/*******************************************************************************
* Function Name : I2C_Start
* Description : Master Start Simulation IIC Communication
* Input : None
* Output : None
* Return : Wheather Start
****************************************************************************** */
uint16_t I2C_Start(void)
{
SDA_H;
SCL_H;
I2C_delay();
if(!SDA_read)return FALSE; //SDA线为低电平则总线忙,退出
SDA_L;
I2C_delay();
if(SDA_read) return FALSE; //SDA线为高电平则总线出错,退出
SDA_L;
I2C_delay();
return TRUE;
}
/**************************************
* I2Cstart: keep SCL high, SDA high to low
* ___________
* SCL: \_____
* ______
* SDA: \__________
* 函数返回时:SDA,SCL均为低电平
***************************************/
uint8_t I2C_Start(void)
{
SDA_H;
SCL_H;
I2C_delay();
if(!SDA_READ)return FALSE;
SDA_L;
I2C_delay();
if(SDA_READ)return FALSE;
SCL_L;
return TRUE;
}
void I2C_Release(void)
{
uint8_t i =9;
while(i--)
{
SCL_H;
I2C_delay();
SCL_L;
I2C_delay();
}
I2C_Stop();
}
// Read a bit from I2C bus
bool i2c_read_bit(void) {
bool bit;
// Let the slave drive data
read_SDA();
I2C_delay();
while (read_SCL() == 0) { // Clock stretching
// You should add timeout to this loop
}
// SCL is high, now data is valid
bit = read_SDA();
I2C_delay();
clear_SCL();
return bit;
}
//IIC发送一个字节
//返回从机有无应答
//1，有应答
//0，无应答
static void IIC_Send_Byte(u8 txd)
{
u8 t;
SDA_OUT();
for(t=0;t<8;t++)
{
IIC_SDA((txd&0x80)>>7);
txd<<=1;
IIC_SCL(1);
I2C_delay();
IIC_SCL(0);
I2C_delay();
}
}
