Posted on April 20, 2016 at 14:06Hi,
In our environment , we have interfaced codec IC with I2C peripheral .
Once codec IC has been configured , both SDA and SCL @ High logic level .
Now if controller reset happened , SDA line remains low and inhibits the STM32 start condition .
To resolve this, I have written following code .
Now if I go for configuring I2C peripheral ,busy flag has been set just after RCC_APB1PeriphClockCmd() API .
Any reason behind this ?
void ResetI2cLines()
{
uint8_t i;
GPIO_InitTypeDef gpio;
// Provid delay before I2c Reset line
DelayMS(1);
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);
// Config SDA and SCL Pin
bzero(&gpio, sizeof(gpio));
gpio.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
gpio.GPIO_Mode = GPIO_Mode_OUT;
gpio.GPIO_OType = GPIO_OType_PP;
gpio.GPIO_PuPd = GPIO_PuPd_UP;
gpio.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &gpio);
GPIO_SetBits(GPIOB, GPIO_Pin_7);
// 9th Pulse NACK signal
for(i=0; i<10; i++)
{
// SCL line Clocking
GPIO_SetBits(GPIOB, GPIO_Pin_6);
DelayUS(5);
GPIO_ResetBits(GPIOB, GPIO_Pin_6);
DelayUS(5);
}
//Stop Signal - SDA Low to High while SCL High
GPIO_ResetBits(GPIOB, GPIO_Pin_7);
DelayUS(5);
GPIO_SetBits(GPIOB, GPIO_Pin_6);
DelayUS(2);
GPIO_SetBits(GPIOB, GPIO_Pin_7);
DelayUS(2);
}
#i2c #stm32f4 #discovery
