STM32 I2C init failed

[ivainc]

Posted on April 13, 2012 at 19:09

ATTENTION! The following code do not work for STM32 I2C while looking good:

void I2C_Ini(void){ I2C_InitTypeDef I2C_InitStructure; NVIC_InitTypeDef NVIC_InitStructure; // I2C RCC RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1,ENABLE); // I2C GPIO RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB,ENABLE); RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE); GPIO_PinRemapConfig(GPIO_Remap_I2C1,ENABLE);// SCL=B8,SDA=B9 PININI(SCL,GPIO_Mode_AF_OD,GPIO_Speed_50MHz);PINLOCK(SCL); //

macros w/o errors

PININI(SDA,GPIO_Mode_AF_OD,GPIO_Speed_50MHz);PINLOCK(SDA);// macros w/o errors // I2C config I2C_InitStructure.I2C_ClockSpeed = 100000; I2C_InitStructure.I2C_Mode = I2C_Mode_I2C; I2C_InitStructure.I2C_DutyCycle = I2C_DutyCycle_2; I2C_InitStructure.I2C_OwnAddress1 = 0xAA; I2C_InitStructure.I2C_Ack = I2C_Ack_Enable; I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit; I2C_Init(I2C1,&I2C_InitStructure); I2C_Cmd(I2C1,ENABLE); // I2C NVIC NVIC_InitStructure.NVIC_IRQChannel = I2C1_EV_IRQn; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure); NVIC_InitStructure.NVIC_IRQChannel = I2C1_ER_IRQn; NVIC_Init(&NVIC_InitStructure); I2C_ITConfig(I2C1,I2C_IT_EVT,ENABLE); // enable event IRQ I2C_ITConfig(I2C1,I2C_IT_ERR,ENABLE); // enable error IRQ I2C_ITConfig(I2C1,I2C_IT_BUF,ENABLE); // enable buffer IRQ } As a result of this init the BUSY bit is set and I2C can't work! The ref manual don't provide any info about this.

#stm32f100c8 #i2c

[Tesla DeLorean]

Posted on April 13, 2012 at 19:39

I think it's nuanced, All examples use I2C_Cmd(I2Cx,ENABLE); prior to I2C_Init()

[ivainc]

Posted on April 14, 2012 at 00:16

It's may be not good idea to enable peripheral which is't properly init.

In my code above if we enable I2C1 clocks AFTER GPIO init - all will be working..

I think, it's strange behaviour for I2C.

[hansen]

Posted on April 14, 2012 at 11:33

Hi,

I am having problem with I2C on STM32F100C8 . I'm not sure if its my code or the I2C peripheral giving the problem.After initialization the code is getting stuck in test on EV6 where I am getting i2c last event as 0x30400(I2C->SR1=0x400 and I2C->SR2=3 and the event I'm expecting is 0x70082(I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED). On the oscilloscope I see that SCL and SDA are high initially and go low after start condition and then SDA goes high and remains high while SCL continues to remain low when I send the device address. Could someone help me to debug this better,Thanks Here is my code snippet,

void
MMA8453Q_I2C_InitBusPins(
void
)
{
I2C_InitTypeDef I2C_InitStructure;
GPIO_InitTypeDef GPIO_InitStructure;
/* Enable I2C and GPIO clocks */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO | RCC_APB2Periph_GPIOB,ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);
GPIO_PinRemapConfig(GPIO_Remap_I2C1, ENABLE);
/* Configure I2C pins: SCL and SDA */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9 | GPIO_Pin_8;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_OD;
GPIO_Init(ACC_I2C_Port, &GPIO_InitStructure);
/* I2C configuration */
I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;
I2C_InitStructure.I2C_DutyCycle = I2C_DutyCycle_2;
I2C_InitStructure.I2C_OwnAddress1 = 0x00;
I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;
I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
I2C_InitStructure.I2C_ClockSpeed = 100000;
/* I2C Peripheral Enable */
I2C_Cmd(I2C1, ENABLE);
/* Apply I2C configuration after enabling it */
I2C_Init(I2C1, &I2C_InitStructure);

}
void
MMA8453Q_I2C_BufferRead(u8 slAddr, u8* pBuffer, u8 ReadAddr, u16 NumByteToRead)
{
/* While the bus is busy */
while
(I2C_GetFlagStatus(I2C1, I2C_FLAG_BUSY));
/* Send START condition */
I2C_GenerateSTART(I2C1, ENABLE);
/* Test on EV5 and clear it */
while
(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_MODE_SELECT));
/* Send MMA8453Q_Magn address for write */
I2C_Send7bitAddress(I2C1, ACC_I2C_ADDRESS_WRITE, I2C_Direction_Transmitter);
/* Test on EV6 and clear it */
while
(!I2C_CheckEvent(I2C1, I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED)); 
//code stuck here
}
unsigned 
char
MMA8453Q_I2C_Init(
void
){
unsigned 
char
i;
MMA8453Q_I2C_InitBusPins();
MMA8453Q_I2C_BufferRead(ACC_I2C_ADDRESS,&i,ACC_WHO_AM_I,1);
if
(i != 0x1a) 
return
(0);
return
(1);
}

[hansen]

Posted on April 17, 2012 at 09:56

Hi Again,

Any views please ?

Thanks

[emalund]

Posted on April 17, 2012 at 17:22

I am having problem with I2C on STM32F100C8 . 

 

I'm not sure if its my code or the I2C peripheral giving the problem.After initialization the code is getting stuck in test on EV6

 

read the errata

[hansen]

Posted on April 18, 2012 at 08:06

Hi,

Thanks for the info,I found there were some problems with the hardware connection on my side.I'm using bit banging for I2C for now ,its working fine.