Posted on July 31, 2014 at 16:30Hello Everyone,
I have started to work on the STM32F0308 discovery board. Now I am trying to read data from the RTC PCF8583 using I2C. I do not have prior experience with I2C.
My problem is that I am not able to read data from the RTC (Output on terminal in Run mode: <0><0><0>) .
Please check my code and let me know what I have done is correct ... Please educate me on this.
CODE:
void usartInit()
{
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_StructInit(&GPIO_InitStructure);
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10 | GPIO_Pin_9;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_Init(GPIOA, &GPIO_InitStructure);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource10, GPIO_AF_1);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource9, GPIO_AF_1);
USART_InitTypeDef USART_InitStructure ;
USART_StructInit(&USART_InitStructure);
USART_InitStructure.USART_BaudRate = 9600;
USART_InitStructure.USART_Mode = USART_Mode_Tx | USART_Mode_Rx;
USART_InitStructure.USART_Parity = USART_Parity_No;
USART_InitStructure.USART_StopBits = USART_StopBits_1;
USART_InitStructure.USART_WordLength = USART_WordLength_8b;
USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
USART_Init(USART1, &USART_InitStructure);
USART_Cmd(USART1, ENABLE);
}
void TIM17_IRQHandler()
{
TIM_ClearITPendingBit(TIM17 ,TIM_IT_Update);
i2c_call();
}
void vTimer17_init()
{
TIM_TimeBaseInitTypeDef TIM_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM17, ENABLE);
TIM_TimeBaseStructInit(&TIM_InitStructure);
TIM_InitStructure.TIM_Prescaler = 4800-1;
TIM_InitStructure.TIM_Period = 100-1;
TIM_InitStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_InitStructure.TIM_ClockDivision = 0;
TIM_TimeBaseInit(TIM17,&TIM_InitStructure );
TIM_Cmd(TIM17, ENABLE);
NVIC_InitStructure.NVIC_IRQChannel = TIM17_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPriority = 3;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init (& NVIC_InitStructure);
NVIC_EnableIRQ(TIM17_IRQn);
TIM_ITConfig(TIM17 , TIM_IT_Update , ENABLE);
}
void i2c_call()
{
uint16_t sec;
I2C_TransferHandling(I2C1, 0xA0,1, I2C_AutoEnd_Mode, I2C_Generate_Start_Write);
I2C_SendData(I2C1, 0x02);
I2C_TransferHandling(I2C1, 0xA1,1, I2C_AutoEnd_Mode, I2C_Generate_Start_Read);
sec = I2C_ReceiveData(I2C1);
I2C_GenerateSTOP(I2C1, ENABLE);
while (USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);
USART_SendData(USART1, sec);
}
void i2c1_init()
{
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOB, ENABLE);
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOC, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_StructInit(&GPIO_InitStructure);
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8 | GPIO_Pin_9;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &GPIO_InitStructure);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource8, GPIO_AF_1);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource9, GPIO_AF_1);
I2C_InitTypeDef I2C_InitStructure;
I2C_StructInit(&I2C_InitStructure);
I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;
I2C_InitStructure.I2C_Ack = I2C_Ack_Disable;
I2C_InitStructure.I2C_OwnAddress1 = 0x5A;
I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
I2C_InitStructure.I2C_AnalogFilter = I2C_AnalogFilter_Disable;
I2C_InitStructure.I2C_DigitalFilter = 0x00;
I2C_InitStructure.I2C_Timing = 0x00B01A4F;
I2C_Init(I2C1, &I2C_InitStructure);
I2C_Cmd(I2C1, ENABLE);
}
int main(void)
{
i2c1_init();
usartInit();
vTimer17_init();
while(1)
{
}
return 0;
}
PS : I know there is an inbuilt RTC in the chip which I am using. But I want to try interfacing with an external RTC and to get some familiarity with I2C.
Thanks in Advance
Prashanth
#discovery #stm32 #i2c #stm32f0
