void I2CStop(void)
{
SDA = 0; // i2c stop bit sequence
I2CDelay();
SCL = 1;
I2CDelay();
SDA = 1;
I2CDelay();
}
void I2C_Configuration(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
I2C_InitTypeDef I2C_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB | RCC_APB2Periph_AFIO, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);
GPIO_PinRemapConfig(GPIO_Remap_I2C1, ENABLE);
GPIO_InitStructure.GPIO_Pin = I2C_SCL_PIN;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD;
GPIO_Init(GPIOB, &GPIO_InitStructure);
GPIO_ResetBits(GPIOB, I2C_SCL_PIN);
I2CDelay(SystemCoreClock / 3 / 100000);
GPIO_InitStructure.GPIO_Pin = I2C_SDA_PIN;
GPIO_Init(GPIOB, &GPIO_InitStructure);
GPIO_ResetBits(GPIOB, I2C_SDA_PIN);
I2CDelay(SystemCoreClock / 3 / 100000);
GPIO_SetBits(GPIOB, I2C_SCL_PIN);
I2CDelay(SystemCoreClock / 3 / 100000);
GPIO_SetBits(GPIOB, I2C_SDA_PIN);
I2CDelay(SystemCoreClock / 3 / 100000);
GPIO_InitStructure.GPIO_Pin = I2C_SCL_PIN;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_OD;
GPIO_Init(GPIOB, &GPIO_InitStructure);
GPIO_InitStructure.GPIO_Pin = I2C_SDA_PIN;
GPIO_Init(GPIOB, &GPIO_InitStructure);
I2C_DeInit(I2C);
I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;
I2C_InitStructure.I2C_DutyCycle = I2C_DutyCycle_2;
I2C_InitStructure.I2C_OwnAddress1 = I2C_SLAVE_ADDR;
I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;
I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
I2C_InitStructure.I2C_ClockSpeed = I2C_SPEED;
I2C_Init(I2C, &I2C_InitStructure);
I2C_Cmd(I2C, ENABLE);
if (I2C->SR2 & 0x02) //检测I2C
{
while (1) //DEBUG
{
}
}
}
char I2CStop(void)
{
SDA_LOW;
SCL_HIGH; /* Let SCL go up */
I2CDelay(I2CDELAY);
SDA_HIGH; /* ...and then SDA up -> stop condition. */
I2CDelay(I2CDELAY);
return (SCL_IN && SDA_IN); /* Both will be up, if everything is fine */
}
void I2CStart()
{
SDA = 1;
I2CDelay();
SCL = 1;
I2CDelay();
SDA = 0;
I2CDelay();
SCL = 0;
I2CDelay();
}
char I2CStart(void)
{
SDA_HIGH;
SCL_HIGH;
I2CDelay(I2CDELAY);
SDA_LOW; /* Pull SDA down... */
I2CDelay(I2CDELAY);
SCL_LOW; /* ...and then SCL -> start condition. */
I2CDelay(I2CDELAY);
return 0;
}
// put SCL to high-z and wait until line is really hi
// returns != 0 if ok
uns8 I2CWaitClkHi(void)
{
uns8 nii=1;
I2CDelay();
I2C_CIO=1; // set SCL to input, output a high
while( I2C_SCL == 0 ) // wait for line to come hi
{
nii++;
if( nii == 0 )
break;
}
I2CDelay();
return(nii);
}
// send a stop condition
void I2CStop(void)
{
I2C_DIO=0; // set SDA to output
I2C_SDA = 0; // output a low
I2CWaitClkHi();
I2C_DIO=1; // set SDA to input, output a high, STOP condition
I2CDelay(); // leave clock high
}
char BitInI2C(void)
{
char bin;
// SDA is opencollector, so:
SDA_HIGH;
SCL_HIGH; /* Let SCL go up */
while(!SCL_IN) /* Wait for other devices */
{
// should do a timeout here
}
bin = SDA_IN; /* Read in data */
I2CDelay(I2CDELAY);
SCL_LOW; /* Pull SCL back up */
I2CDelay(I2CDELAY);
return bin; /* Return the sampled bit */
}
// send a start condition
void I2CStart(void)
{
I2C_DIO=1; // set SDA to input, output a high
I2CWaitClkHi();
I2C_SDA = 0; // start condition
I2C_DIO = 0; // output a low
I2CDelay();
I2C_SCL = 0;
I2C_CIO = 0; // set SCL to output, output a low
}
unsigned char I2CGet(char ack)
{
char x, d=0;
SDA = 1;
for(x=0; x<8; x++) {
d <<= 1;
do {
SCL = 1;
} while(SCL_IN==0); // wait for any SCL clock stretching
I2CDelay();
if(SDA_IN)
d |= 1;
SCL = 0;
}
if(ack) SDA = 0;
else SDA = 1;
SCL = 1;
I2CDelay(); // send (N)ACK bit
SCL = 0;
SDA = 1;
return d;
}
char BitOutI2C(unsigned char bout)
{
SDA_OUT(bout); /* Put data out on SDA */
I2CDelay(I2CDELAY);
SCL_HIGH; /* Let SCL go up */
while(!SCL_IN) /* Wait until all other devices are ready */
{
// should do a timeout here
}
if (SDA_IN != bout) /* Arbitration lost, release bus and return */
{
SDA_HIGH; /* Should be up anyway, but make sure */
i2cError = I2CERR_LOST;
I2CDumpError(i2cError);
return 1;
}
I2CDelay(I2CDELAY);
SCL_LOW; /* Pull SCL back down */
I2CDelay(I2CDELAY);
return 0; /* OK */
}
unsigned char I2CPut(unsigned char d)
{
char x;
unsigned char b;
for(x=8; x; x--) {
if(d&0x80) SDA = 1;
else SDA = 0;
SCL = 1;
d <<= 1;
SCL = 0;
}
SDA = 1;
SCL = 1;
I2CDelay();
b = SDA_IN; // possible ACK bit
SCL = 0;
return b;
}
char I2CSendReceive(char addr, char tx_count, char rx_count)
{
if (I2CSendStop(addr, tx_count, 0))
{
/* If send fails, abort but don't send a stop condition if we lost
arbitration */
if (i2cError != I2CERR_LOST) I2CStop();
return 1;
}
SDA_HIGH; /* One of these may be low now, in which case the next */
SCL_HIGH; /* start condition wouldn't be detected so make */
I2CDelay(I2CDELAY); /* sure that they're up and wait for one delay slot */
if (i2c_recv((char)(addr|0x01), rx_count)) return 1;
return (i2cError ? 1 : 0);
}
