/**
* @brief Main program.
* @param None
* @retval None
*/
int main(void)
{
int i;
RCC_Configuration();
GPIO_Configuration();
I2C_Configuration();
i=0;
/* Enable I2C2 */
I2C_Enable(BOARD_I2C,ENABLE);
/* Enable Acknowledge */
I2C_Acknowledge_Enable(BOARD_I2C,ENABLE);
/* Send a NACK for the next data byte which will be received into the shift register */
I2C_NACKPosition_Enable(BOARD_I2C,I2C_NACKPOSITION_NEXT);
/* Wait until I2C Bus is idle */
while(I2C_GetBitState(BOARD_I2C, I2C_FLAG_I2CBSY));
/* Send a start condition to I2C bus */
I2C_StartOnBus_Enable(BOARD_I2C, ENABLE);
/* Wait until SBSEND bit is set */
while(!I2C_StateDetect(BOARD_I2C, I2C_PROGRAMMINGMODE_MASTER_SBSEND));
/* Send slave address to I2C bus */
I2C_AddressingDevice_7bit(BOARD_I2C, SLAVE_ADDRESS7, I2C_DIRECTION_RECEIVER);
/* Disable ACK before clearing ADDSEND bit */
I2C_Acknowledge_Enable(BOARD_I2C, DISABLE);
/* Wait until ADDSEND bit is set and clear it */
while(!I2C_StateDetect(BOARD_I2C, I2C_PROGRAMMINGMODE_MASTER_RECEIVER_ADDSEND));
/* Wait until the last data byte is received into the shift register */
while(!I2C_GetBitState(BOARD_I2C, I2C_FLAG_BTC));
/* Send a stop condition */
I2C_StopOnBus_Enable(BOARD_I2C, ENABLE);
/* Wait until the reception data register is not empty */
while(!I2C_GetBitState(BOARD_I2C, I2C_FLAG_RBNE));
/* Read a data from I2C_DTR */
BOARD_I2C_Buf_Read[i++]=I2C_ReceiveData(BOARD_I2C);
/* Wait until the reception data register is not empty */
while(!I2C_GetBitState(BOARD_I2C, I2C_FLAG_RBNE));
/* Read a data from I2C_DTR */
BOARD_I2C_Buf_Read[i++]=I2C_ReceiveData(BOARD_I2C);
while(BOARD_I2C->CTLR1&0x0200);
I2C_NACKPosition_Enable(BOARD_I2C,I2C_NACKPOSITION_CURRENT);
/* Enable Acknowledge */
I2C_Acknowledge_Enable(BOARD_I2C, ENABLE);
while(1);
}
void i2c_init(void)
{
// RCC_AHBPeriphClock_Enable(RCC_AHBPERIPH_GPIOB,ENABLE);
RCC_APB1PeriphClock_Enable(RCC_APB1PERIPH_I2C1, ENABLE);
GPIO_InitPara GPIO_InitStructure;
GPIO_InitStructure.GPIO_Pin = GPIO_PIN_6 | GPIO_PIN_7;
GPIO_InitStructure.GPIO_Mode = GPIO_MODE_IN;
GPIO_InitStructure.GPIO_Speed = GPIO_SPEED_50MHZ;
GPIO_InitStructure.GPIO_OType = GPIO_OTYPE_OD;
GPIO_InitStructure.GPIO_PuPd = GPIO_PUPD_PULLUP;
GPIO_Init(GPIOB, &GPIO_InitStructure);
// the following checks deal with issues arrising from i2c being stopped while the gyro is sending data
// this happens mainly in debug mode and perhaps at low voltage reset
int i2cfail = 0;
// sda is set with pullup
// if sda is low the gyro might have become stuck while waiting for clock(and is sending a "zero")
if (Bit_RESET == GPIO_ReadInputBit(GPIOB, GPIO_PIN_7))
{
i2cfail = 1;
}
delay(10);
GPIO_InitStructure.GPIO_Pin = GPIO_PIN_7;
GPIO_InitStructure.GPIO_PuPd = GPIO_PUPD_PULLDOWN;
GPIO_Init(GPIOB, &GPIO_InitStructure);
// sda is set with pulldown
// if sda is high it could be because the gyro is stuck sending data
if (Bit_SET == GPIO_ReadInputBit(GPIOB, GPIO_PIN_7))
{
i2cfail = 1;
}
if (i2cfail)
{
// set sda pullup so it sends an ack
GPIO_InitStructure.GPIO_Pin = GPIO_PIN_7;
GPIO_InitStructure.GPIO_PuPd = GPIO_PUPD_PULLUP;
GPIO_Init(GPIOB, &GPIO_InitStructure);
GPIO_InitStructure.GPIO_Pin = GPIO_PIN_6;
GPIO_InitStructure.GPIO_Mode = GPIO_MODE_OUT;
GPIO_InitStructure.GPIO_PuPd = GPIO_PUPD_PULLUP;
GPIO_Init(GPIOB, &GPIO_InitStructure);
delay(10);
for (int i = 0; i < 18; i++)
{ // send 9 clock pulses on scl to clear any pending byte
GPIO_WriteBit(GPIOB, GPIO_PIN_6, Bit_RESET);
delay(25);
GPIO_WriteBit(GPIOB, GPIO_PIN_6, Bit_SET);
delay(5);
if (Bit_RESET != GPIO_ReadInputBit(GPIOB, GPIO_PIN_7))
{
break;
}
}
}
// actual i2c setup
GPIO_InitStructure.GPIO_Pin = GPIO_PIN_6 | GPIO_PIN_7;
GPIO_InitStructure.GPIO_Mode = GPIO_MODE_AF;
GPIO_InitStructure.GPIO_Speed = GPIO_SPEED_50MHZ;
GPIO_InitStructure.GPIO_OType = GPIO_OTYPE_OD;
GPIO_InitStructure.GPIO_PuPd = GPIO_PUPD_PULLUP;
GPIO_Init(GPIOB, &GPIO_InitStructure);
GPIO_PinAFConfig(GPIOB, GPIO_PINSOURCE6, GPIO_AF_1);
GPIO_PinAFConfig(GPIOB, GPIO_PINSOURCE7, GPIO_AF_1);
I2C_InitPara I2C_InitStructure;
I2C_InitStructure.I2C_Protocol = I2C_PROTOCOL_I2C;
I2C_InitStructure.I2C_DutyCycle = I2C_DUTYCYCLE_2;
I2C_InitStructure.I2C_BitRate = 400000;
I2C_InitStructure.I2C_AddressingMode = I2C_ADDRESSING_MODE_7BIT;
I2C_InitStructure.I2C_DeviceAddress = 0x24;
I2C_Init(I2C1, &I2C_InitStructure);
I2C_Enable(I2C1, ENABLE);
I2C_Acknowledge_Enable(I2C1, DISABLE);
I2C_NACKPosition_Enable(I2C1, I2C_NACKPOSITION_CURRENT);
}
